I prepared baked chicken for supper 2 weeks ago.  American chickens are nice and fat but for some dishes they are too fat.  I removed the skin from the chicken pieces before rolling them in cracker crumbs and black pepper.  This reduces the unwanted grease that nutritionists claim clog our arteries.  However, I hate wasting food, so I boiled the chicken skins and put some of them with the broth in a bowl for the cat.  I placed the bowl on the back step.  A few minutes later, I looked out the window to see if the cat was enjoying his warm treat on such a frosty night.  Instead, an unidentifiable gray object was over the bowl.  I turned on the light and saw an opossum.  I ran to fetch my camera, but when I opened the door, the creature scurried away quickly, a piece of chicken skin dangling from its mouth.    Later, the possum returned and I took a decent photograph of it.

I discovered this opossum eating food I put on the back step for my cat.

The feral cat that I tamed (see:http://markgelbart.wordpress.com/2014/06/24/mr-claw/) used to eat every speck of food I placed outside.  But now that he realizes I’m going to feed him everyday, he doesn’t devour every bit at once.  There’s no telling how often that opossum has been scavenging cat food.  Possums are quite common in my neighborhood.  Several weeks ago, I saw a road-killed possum down the street that a flock of vultures made disappear in less time than it took me to jog 3 miles.

The Virginia opossum (Didelphis virginiana) is an amazing survivor.  Opossum remains are found in just about every Pleistocene-aged fossil site in Georgia, and they are still abundant today.  Their rapid rate of reproduction is their most important survival attribute.  They become sexually mature at 6 months, and their gestation period is less than 2 weeks.  They produce up to 18 young but the females only have 13 nipples.  An average of 7 young survive to adulthood.  Nevertheless, in about a year’s time 2 opossums can result in roughly a 20 fold increase.  When attacked by a large predator, opossums can escape by climbing a tree.  Their prehensile tails allow them to hang upside down from branches, giving them a good view of potential threats.  If they are unable to make it to a tree when attacked, their nervous system becomes overwhelmed, and they literally shit and faint.  The noxious fluid that leaks from their anus makes them unappetizing to predators.  Unless a predator is especially hungry, the lack of movement and bad smell will cause them to lose interest.  The opossum then recovers and goes on with its business.

Opossums are also omnivorous–another contributing factor to their success as a species.  They eat fruit, carrion, insects, worms and grubs, birds and eggs, small mammals, reptiles, and even venomous snakes.  They are immune to rattlesnake venom.  A recent study found there is an evolutionary arms race between opossums and pit vipers.  Scientists discovered opossums have rapidly evolving gene codes for Von Willibrandt’s Factor, an important blood-clotting protein targeted by snake venom.  Natural selection has strongly favored those individuals of the opossum population immune to snake venom.  Creationists often use “living fossils” such as the opossum as evidence that evolution doesn’t occur.  They are wrong.  Although the modern Virginia opossum is anatomically identical to the opossum of 3 million years ago, its physiology has evolved considerably.  If we could bring an opossum from 2 million years ago to the present, it would likely not be able to survive the bite of a modern day rattlesnake like its modern day descendents can.

The opossum is 1 of the oldest species of North American mammals.  Ancestral opossums first evolved about 65 million years ago when the dinosaurs became extinct.  This is also the time when the shared ancestry of American opossums and Australian marsupials diverged.  These ancestral species of opossums became extinct in North America about 25 million years ago, but they continued to live in South America which at that time had become an island continent.  A landbridge emerged 3 million years ago, connecting North and South America, and this is when Virginia opossums moved north.  At least 103 species of opossums live in South America, but only 1 evolved the ability to survive in the temperate climates that occur in North America.  All the other species are restricted to tropical climates.  There are 5 other species of opossums in the Didelphis genus that are closely related to the North American opossum.  There are also 4-eyed opossums (they don’t actually have 4 eyes), 14 species of woolly opossums, 20 species of short-tailed oppossums, 56 species of diminutive mouse opossums, and a water opossum well adapted to a semi-aquatic existence.

Reference:

Jansa, Sharon A.; and Robert Voss

“Adaptive Evolution of the Venom-Targeted vWF Protein in Opossums that eat Pit Vipers”

Plos One 6 (6) 2011

The giant beaver of the Pleistocene was semi-aquatic like its modern living cousin (Castor canadensis), but it ate different plant foods, and therefore occupied a different ecological niche.  Giant beaver fossils are fairly common throughout the midwest but have also been found at numerous localities in the southeast, particularly Florida.  Scientists formerly thought southern giant beavers were the same species (Casteroides ohioensis) that ranged throughout the midwest and northeast.  The reason for this misconception was the lack of complete skulls in the collections of southern museums.  Skulls of giant beavers were excavated from the Leisey Shell Pits in Florida, but this site dates to the early Pleistocene, and paleontologists thought they represented a species that was ancestral to the late Pleistocene giant beaver, thus explaining the differences in skull characteristics.  However, a complete skull resembling those early Pleistocene giant beavers was discovered in the Cooper River in South Carolina, and this was from a late Pleistocene deposit.  Recently, paleontologists got their hands on 2 more giant beaver skulls dating to the late Pleistocene of Florida.  Scuba divers found 1 in Lake Rousseau, and the other was found in the Aucilla River.  After a careful anatomical analysis, scientists determined the late Pleistocene giant beaver of Florida, coastal Georgia, and coastal South Carolina was a different species than the giant beaver of the midwest and northeast.  They gave it the scientific name Casteroides dilophidus.

Size comparison between the Pleistocene giant beaver and the extant beaver.  The 2 species co-existed for 2 million years.  Scientists recently realized there were 2 different species of giant beaver–a northern and a southern.

Casteroides dilophidus had a shorter ridge on the top of its skull than C. ohioensis.  This ridge is known as the saggital crest.  One of its skull sutures bears in a different direction than that same suture on C. Casteroides, and C. dilophidus’s cheek row teeth are located differently in relation to the zygomatic arch.  The projection of the frontal bone of the eye socket is “better developed” in C. dilophidus than in C. casteroides, according to the study.  Some C. dilophidus specimens have grooves in their teeth that are never found in C. casteroides, but this can’t always be used as a distinguishing characteristic.  The authors of the study don’t have enough data to determine whether giant beaver fossils found in the mid-south (Alabama, Arkansas, Mississippi, and Tennessee) belong to C. dilophidus or C. ohioensis, so they suggest classifying those specimens as Casteroides sp.  Many fossil specimens (mostly teeth) of Casteroides have been found in the mid-south but no complete skulls.

Casteroides preferred treeless freshwater marshes where they could feed on the aquatic plants that flourished in full sunlight.  Wooded swamps and bottomlands are too shady for the plants they liked to eat.  Much erroneous speculation surmises modern extant beavers outcompeted Casteroides.  Instead, the smaller species of beaver created habitat favorable to Casteroides.  Extant beavers fell trees and open up the forest canopy, allowing succulent shade-intolerant vegetation to thrive.  Old beaver ponds eventually become filled with sediment and are converted to the wet treeless marshes Casteroides required.  Moreover, Casteroides co-existed with Castor canadensis for 2 million years.

An ecological cycle of alternating beaver species during the Pleistocene is apparent.  Castor canadensis converted wooded swamps and bottomlands to treeless marshes.  When trees became scarce, Castor canadensis would abandon the locality while Casteroides would move in. But Casteroides didn’t eat trees, allowing the forest to grow back. Castor canadensis would then recolonize the location as Casteroides moved away in search of a more open habitat.  The presence of both species in the fossil record reflects a varied environment and a much more diverse ecosystem than exists today.

Reference:

Hulbert, R. C.; A. Kirne, and G.S. Morgan

“Taxonomy of the Pleistocene Giant Beaver Casteroides (Rodentia: Casteroidae) from Southeastern U.S.”

Bulletin of the Florida Museum of Natural History 53 (2) 2014

Today, the antelope jack rabbit is restricted to desert grassland habitat in western Mexico and southern Arizona, but during the Pleistocene it occurred as far east as Florida.  Fossils of this species have been found at 2 sites in Florida, dating to the middle Pleistocene.  Over 50 fossils of unidentified hare species (Lepus sp.) that probably also were antelope jack rabbits have been found at many sites in Florida, dating to the early Pleistocene and the Pliocene.  The early Pleistocene/late Pliocene climate was much drier than it is today, and desert grassland habitat was more prevalent.  Several species of pronghorns lived in the southeast as well.  Antelope jack rabbits gradually declined in abundance and may have disappeared from the southeast completely by the late Pleistocene, but the fossil record is so incomplete that there is no way of knowing exactly when they became extirpated from the region.

Caves located in arid climates preserve ground sloth dung that is tens of thousands of years old.  The shasta ground sloth (Nothrotheriops shastensis) ranged throughout the American southwest during the late Pleistocene and left telltale evidence of its diet in several of these caverns including Rampart Cave, Arizona; Shelter Cave, New Mexico; and Gympsum Cave, Nevada.  From the macrofossils and DNA evidence in this dung we know this species ate a wide variety of plants–pine, mulberry, mustards, agave, yucca, grass, mint, globe mallow, saltbush, Mormon tea, grape, water leaf, creosote bush, hop sage, sagebrush, and willow.  There is no evidence from these coprolites that ground sloths ate meat.  Nevertheless, some scientists hypothesize ground sloths did scavenge meat .   Although ground sloths were too slow to actively hunt most prey, they could have taken advantage of available carrion, and perhaps even usurped the kills of predators.  Ground sloths were powerful beasts with long claws capable of severely injuring a carnivore contesting ownership of a carcass.  Some scientists have even suggested ground sloths could have actively turned over glyptodonts to attack their vulnerable underbelly.

The lack of meat in known sloth coprolites doesn’t preclude the possibility they did on occasion eat animal protein.  Over 99% of white-tail deer feces will show no evidence of flesh-eating.  Yet, we know they do sometimes scavenge meat and even prey on nestling birds and eggs (See: http://markgelbart.wordpress.com/2012/05/11/unexpected-items-in-the-diet-of-the-white-tail-deer/)  Without evidence the hypothesis that ground sloths ate meat is mere speculation.  However, evidence from 1 specimen supports this hypothesis.

Artist’s rendition of a Megatherium, a large ground sloth that formerly lived in South America.  The deer in the foreground is a pampas deer (Ozotoceros bezoarticus)), still extant but very rare.

Photo of a rib interpeted to have been gnawed on by a Megatherium.  From the below referenced book.

A fragmentary rib in the collection of a museum in Uruguay has gnaw marks on it that match the teeth of Megatherium americana, a large ground sloth.  The rib is from either another ground sloth or a mastodon.  (Scientists can’t differentiate among these 2 species from just this part of the anatomy.)  It has 7 shallow marks.  Weathering marks exist over the tooth marks, eliminating the possibility that natural abrasions caused the scratches.  The marks are too dull to have been the result of human cutting.  The marks don’t match those of rodents or carnivores.  However, they exactly match the “transversely bilophodont” teeth of a megatherium.  The spacing of the tooth marks also match the distance between the bottom teeth of a megatherium.  The scientist who examined the marks believes the sloth held the bone upside down and gnawed on it with its bottom teeth.

If sloths ate carrion, I’m sure they would have also eaten ground-nesting bird nestlings and eggs as well.  They likely snacked on insects.  Ground sloths are related to armadilloes and anteaters.  Armadilloes eat carrion, small mammals, eggs, and insects.  Ground sloths probably retained the ability to digest animal protein from their shared ancestry with armadilloes. The evolutionary ancestor of both lines was likely omnivorous.  There’s no reason to assume ground sloths could not have taken advantage of an easy source of protein, though their diet was primarily vegetarian.  This feeding strategy would not be unlike those of bears, hogs, and apes.

Reference:

Farina, Richard; Sergio Vizcaino, and Gerry Del Iuliis

Megafauna: Giant Beasts of Pleistocene South America

Indiana University Press 2013

Poinar, Henrick; et. al.

“Molecular Coproscopy: Dung and Diet of the Extinct Ground Sloth, Nothrotheriops shastensis”

Science 281 (5375) 1998

Organisms with separate male and female sexes evolved from hermaphroditic ancestors.  Hermaphroditic species are still common.  Many species of plants and some species of animals are able to self-fertilize because they are both male and female.  One would think the evolution of an hermaphroditic organism to a species with separate male and female sexes happened so long ago that it would be impossible for biologists to study.  But, surprisingly, this is not true.  There are over 100 species of plants in the evolutionary process of transitioning between hermaphroditism to a state of separate sexes.  The most familiar species in this transitional state is the wild strawberry, Fragaria virginiana.

Biologists believe the evolution of separate sexes was the result of a beneficial mutation.  Organisms that have separate sexes have increased genetic variation, thus improving the chances the species will survive.  Hermaphrodites suffer higher rates of inbred defects and eventually are eliminated from transitioning populations by the hybrid vigor of male x female combinations.  In stressful environments organisms with separate male and female sexes can allocate resources to seed or pollen, not both–another advantage over the hermaphrodite.

Plants rely on wind and insect pollination.  Males and females of many primitive aquatic animals release sperm and egg in each other’s vicinity, relying on water flow to aid fertilization.  But the evolution of a structure to directly deliver a male’s sperm inside a female’s body was a great advance.  This structure is known as a penis.  The oldest known penis in the fossil record belonged to an extinct species of shrimp (Colymbosathon ecplecticas) that lived 425 million years ago. 

Mammoths and mastodons had the largest penises of any land mammal during the Pleistocene and theirs was comparable in size to those of modern day elephants.

This bull elephant is in the mood to mate.  Note the large penis.  Mammoths and mastodons had the largest penises of any Pleistocene land mammal.

Homo sapiens has the largest penis of any primate.  There’s no evidence Pleistocene humans ever practiced the bizarre and barbaric practice of genital mutilation known as circumcision.  Circumcisions originated in Egypt about 4400 years ago. Religious fanatics in the ancient Egyptian culture rejected the concept of sexual pleasure.  Circumcision spread throughout the Middle East and Africa and was always popular among religious nuts who thought sexual pleasure was bad.  According to the bible (an unreliable source), the early Jews practiced circumcision, but Moses outlawed the practice.  Joshua brought circumcision back because he wanted his men to focus on smiting gentiles rather than sexual pleasure.  Jews have continued this idiotic tradition ever since.  Circumcision became popular in the United States after the Civil War when once again religious nuts were trying to stop boys from masturbating.   It didn’t work–98% of circumcized males admit to masturbating.  Greedy physicians made up falsehoods, supporting the pro-circumcision crusade, so they could make money on a common but unnecessary procedure.  Even today, most American males suffer genital mutilation shortly after birth, though, thankfully, rates are declining.

About a decade ago, the American Academy of Pediatricians admitted there was no medical reason for male circumcisions.  However, in 2012 religious nuts pressured the AAP to restate their position.  The AAP now states, “the health benefits of circumcision outweigh the risks but the existing scientific evidence is not sufficient to warrant universal circumcision…the final decision should be left to parents to make in context of their religious, ethical, or cultural beliefs.”  So in other words, the AAP is saying it’s ok to torture a baby, if their parent’s religion tells them they are supposed to.  The words cowardly and callous come to mind.

The CDC recently released a report supporting the practice of circumcision because in Africa circumcized men are less likely to spread HIV than uncircumcized men.  Well, first of all, the CDC represents America not Africa.  Second, this reasoning is incredibly illogical.  The spread of HIV could be be completely eliminated if every man had their entire penis cut off, just like broken legs could be prevented with universal leg amputations.  Or less dramatic measures could be taken.  Men could use condoms or engage in sex with less dodgy partners.

There is no medical reason for male circumcision.  There is no significant statistical difference in rates of penile cancer or urinary tract infections between circumcized and uncircumcized men as some have falsely claimed.  There is no moral justication for torturing babies, and I think it is sickening how so many parents are willing to approve of such a stupid, barbaric, religious tradition.  The practice of circumcision, both male and female, should be outlawed.

Comparison between a normal penis and the more common (in the U.S.) mutilated penis.

I’m glad I can’t remember my circumcision.  Most American males are strapped down when they are babies and have 12 inches of skin cut off from the most sensitive area of their body…all in the name of religion and tradition.  WHAT AN OUTRAGE!  Are people this insensistive, gullible, and stupid that they would subject their children to torture, just because some stupid rabbi or greedy doctor says they should?

The removal of the foreskin slices off the 5 most sensitive areas of the penis.  Circumcized men are 4.5 times more likely to use erectile dysfunction drugs than uncircumcized men.  These men probably wouldn’t need such medication, if their penises had not been mutilated with the approval of their brainwashed parents.

Reference:

Ashman, T.

“The Evolution of Separate Sexes: A Focus on the Ecological Context”

In chapter 11 of The Ecology and Evolution of Flowers edited by Lawrence Hader and Spencer Barrett

Oxford University Press 2007

Glyptodonts were unlike any living species of mammal.  A carapace, attached to their hips, covered all of their body except for the head.  This protected them from most predators, though evidence from 1 specimen suggests a frontal attack by a big cat could prove fatal (See:http://markgelbart.wordpress.com/2011/11/02/specimen-f-am-95737/).  Their shell provided a wonderful defense, but glyptodonts were capable of taking the offensive.  When confronted by a predator, a glyptodont turned its back and swung its tail with devastating force.  Paleontologists have determined these tail blows were powerful enough to damage the carapace of other glyptodonts.  They also hypothesize of the existence of a fatty pad behind the shoulder that helped withstand these intraspecific blows.  Male glyptodonts fighting over mates turned their backs to each other and swung their tails, battering each other’s carapace.  Occasionally, these blows caused carapaces to fracture.  There is 1 specimen in a South American museum that shows evidence of such an injury, though the wound healed and this individual glyptodont survived.  Some species of glyptodonts had clubs or spikes on their tails.  They were located where the center of percussion would be.  The center of percussion is the equivalent of the “sweet spot” on a baseball bat or tennis racquet.

A glyptodont shell mounted in a South American museum.  A glyptodont mounted in another musuem shows a fracture from being hit by another glyptodont’s tail club.  That carapace healed.

Here’s an artist’s rendition of glyptodonts battling over a mate.

Glyptodonts belonged to the edentate order (some scientists prefer to call it the xenartha order), a classification that includes armadilloes, anteaters, and sloths.  The edentates originally evolved in South America, but some species spread to North America when a landbridge between the continents emerged millions of years ago.  There were 5 genera of glyptodonts living in South America during the Pleistocene, but only 1 species occurred in southeastern North America during the late Pleistocene.  The North American species lived in Florida and the southeastern coastal plain during warm climate phases.  The largest species of glyptodont lived in South America.  This member of the Doedicurus genus reached 4000 pounds.  Glyptodonts were a successful lineage of mammals that lived for tens of millions of years but became extinct about the same time man appears in the archaeological record.  I have no doubt their otherwise well adapted defenses were useless against hunting humans.  A man could simply run forward and hit a glyptodont over the head while avoiding the tail blows.  The fatty deposit behind a glyptodont’s shoulder would have been a delicacy.

Ankylosaurs and glyptodonts are a good example of convergent evolution.  Ankylosaurs, a dinosaur that became extinct 65 million years ago, also had carapaces and swung their tails in self defense in battles over mates.

Ankylosaurs had a similar adaptation as glyptodonts–an example of convergent evolution.

References:

Alexander, R.

“Tail Blow Energy and Carapace Fractures in Large Glyptodont (Mammalia: Xenartha)”

Zoological Journal of the Linnean Society  126 1999

Blanco, Ernesto; Washington jones, and Andres Ringle Knecht

“The Sweet Spot of a Biological Hammer: The Centre of Percussion of a Glyptodont (Mammalia: Xenartha)”

Proceedings of the Royal Society of Biological Science 276 (1675) 2009

South America broke from Antartica and Australia about 60 million years ago and became an island continent where its fauna evolved in isolation.  The most common mammals were marsupials, edentates, and primitive hooved animals unfamiliar to most non-paleontologists.  Circa 30 million years ago, caviomorph rodents and monkeys arrived from Africa via clumps of floating vegetation originating from that continent.  During this time Africa and South America were closer together than they presently are.  Floods in African rivers must have carried these little islands of vegetation with their clinging inhabitants  far into the sea where favorable currents brought the lucky animals to South America.  These new colonizers diversified into many species.  South America remained an isolated continent until 9 million years ago when volcanic islands began emerging  below North America.  Although there was not yet a landbridge between the 2 continents, the fossil record shows there was an early exchange of species.  Ground sloths went north, while tapirs, peccaries, and primitive mastodons known as gompotheres went south.  All of these animals are excellent swimmers.  Apparently, they island-hopped, swimming to reach new islands and eventually coming to a continent where they became successful newcomers.

Elephants can swim for miles without getting tired.  They can breath through their trunks while swimming.  This explains how gompotheres (an elephant-like beast) colonized South America 9 million years ago, long before a land connection existed between the 2 continents.

Tapir swimming.  They can breath through their snouts while swimming submerged.  All of the early colonizers in the Great American Biotic Interchange were excellent swimmers.  They island-hopped before the existence of a complete land connection.

A now extinct relative of the raccoon (Cyonasaura) was next to colonize South America 7.3 million years ago.  An extinct species of raccoon (Chapmalania) that was as large as a bear lived in South America during the Pliocene.  Sygmodontine rodents (rats, mice, gophers) from North America arrived in South America 6 million years ago.  Pampatheres (a giant armadillo) and the terror bird spread to North America 5 million years ago.  They were followed by glyptodonts and capybaras 4 million years ago.  The Central American landbridge emerged above sea level ~3 million years ago bringing a cavalcade of animals south–llamas, horses, canids, and weasels; while porcupines headed north.  A new climatic phase ~2 million years ago allowed even more mammals to head south–deer, rabbits, skunks, cats, and bears.

Other vertebrates took advantage of newly available habitat.  South American forms that moved north included cichlid fish, bufo toads, tree frogs, parrots, tanagers, hummingbirds, and flycatchers.  North American vertebrates that went south included lungless salamanders, ranid frogs, snapping turtles, wood turtles, trachemys turtles, rattlesnakes and other pit vipers, coral snakes, sparrows, and condors.

These faunal invasions occurred in pulses influenced by changes in climate.  During Ice Ages sea level fell and this greatly expanded the land area of Central America.  Average temperatures fell by as much as 14 degrees F here, though because the region is so close to the equator they were not subfreezing.  Nevertheless, pollen records indicate tropical forests were replaced with grassy savannahs and temperate species of trees such as oak, sweetgum, myrtle, elm, walnut, and even spruce and fir at higher elevations.  The change to a more open environment allowed horses and llamas to traverse Central America to colonize land further south.  Warm interglacial conditions favored the expanded ranges of tropical species such as very large ground sloths and glyptodonts.  These species eventually made it to southeastern North America.  Some lineages of mammals colonized 1 continent, evolved to a new species, then returned to the original continent of their ancestor.  Examples of these are the collared peccary and jaguarundi.

More species of South American-originating fauna survive in North America than vice-versa, but most are restricted to the Central American tropics.  There are many species of edentates, marsupials, monkeys, and caviomorph rodents here.  But, excepting Central America’s faunal composition, North America’s invasion to South America could be considered more successful.  There are just 4 successful South American species living today in North America (not counting Central America)–opossum, armadillo, porcupine, and nutria whereas South America is home to tapirs, peccaries, llamas, foxes, cats, sygmodontine rodents, squirrels, rabbits, and shrews.  However, a modern review of this disparity is misleading.  Ground sloths, glyptodonts, and pampatheres were quite successful during the Pleistocene in North America, but humans caused their extinction.  Toxodons and litopterns (primitive South American hooved animals that made it as far north as Mexico) were also vulnerable to human hunting and would likely still live today if not for man.  North America also has a more temperate climate. It is difficult for species that evolved in tropical climates to adapt to freezing temperatures.  The only real losers resulting from this faunal interchange were South America’s marsupial carnivores and the terror birds.  North America’s carnivores eventually outcompeted South America’s meat-eaters.

Reference:

Woodburne, M.O.

“The GABI: Dispersals, Tectonics, Climate, Sea Level, and Holding Pens”

Journal of Mammalian Evolution 17 2010

The National Academy of Science often publishes some really bad studies.  Two years ago, the journal of this organization published a paper entitled “Severe Mammal Declines Coincide with the Proliferation of Burmese Pythons in Everglades National Park.”  This study was authored by Michael Dorcas, an herpetologist from Davidson College, along with a long list of other scientists.  I’m always leery of studies with a long list of contributing scientists.  I suspect the lead authors of these studies do most of the work, and misleadingly include many co-authors.  With minimal input, the many co-authors lend legitimacy to a study in exchange for getting the publishing credit that is so important for their academic careers.

Michael Dorcas.  This scientist authored a really bad study of Burmese pythons that led him to conclude they were wiping out mammal populations in the Everglades National Park.  His study was debunked by the Florida Fish and Wildlife Conservation Commission.  Nevertheless, the media took his ridiculous conclusions as gospel.  Not a single journalist questioned this terrible amateurish study.

I read Dr. Dorcas’s study and knew the results didn’t fit within ecological reality.  He went back to records of road-killed animals in Everglades National Park during the 1990’s before the population of Burmese pythons had become significant and compared them with the number of road side sightings of these same species 10 years later.  He concluded that the populations of raccoons, possums, bobcats, and marsh rabbits had been decimated and in some cases had been reduced by 100%.  This doesn’t make any sense ecologically.  If the population of prey declines in abundance, than the population of predators declines as well because there is nothing for the predators to eat.  Burmese pythons couldn’t decimate mammal populations without eventually succombing to starvation themselves.  So the results of Dr. Dorcas’s study were unbelievably ridiculous.  Nevertheless, every news media outlet picked up this alarmist nonsense and not a single journalist questioned the credibility of such an absurd conclusion.  This demonstrates the ignorance of basic ecology among the average layperson.  I mentioned my logical objections to this study’s findings on my blog about a year ago but thought I was a lone voice in the wilderness.  However, I discovered someone from The Florida Fish and Wildlife Conservation agrees with me.  They found the following flaws in Dr. Dorcas’s study.

1. The survey for road-killed animals (Dr. Dorcas’s data from the 1990’s) didn’t include critical information–how many observers, the number of miles driven, the number of days the survey was done, and the procedures used to avoid double counting.  In other words this data is anecdotal and useless.

2. The year of the pre-python survey was a high water year when more animals were forced to take refuge on the high ground where the road exists.  This explains why more animals were counted during the survey than during later drought years.  Road-side surveys yield dubious data.  Dr. Dorcas should have used live trapping to get an accurate count of mammal populations.

3. There is no actual data on python densities.

4. The timing of the python population increase and the supposed decline in mammal populations is not documented.  Scientists can’t explain how python populations could increase following prey population declines (my point exactly).

5. There is no mention in Dr. Dorcas’s study of coyotes.  Coyotes recently re-colonized south Florida and may play a role in the decline of mammal populations there.

6. The differences in prey density inside and outside Everglades National Park are likely due to differences in habitat, not the presence of pythons.  Everglades National Park is actually very poor wildlife habitat.  More wildlife lives outside the park than inside.  With very few exceptions most of the best wildlife habitat left in the world is occupied by humans.  We give animals the wastelands that are too expensive to commercially develop and call them national parks.

Burmese python killed by alligator.  Burmese pythons are beneficial additions to Florida’s ecology, despite what alarmist environmentalists claim.  South Florida’s ecology was in desperate need of a large predator.

Contrary to the claims of alarmist environmentalists, Burmese pythons are a beneficial addition to South Florida’s ecosystem.  During the Pleistocene in this region there were 5 species of big cats plus dire wolves, bears, and alligators.  Now, there are just alligators and pythons.  (Very few Florida panthers live in Everglades National Park.  Most occur on cattle ranches located well north of the park.) Without the presence of large predators, the populations of smaller predators such as raccoons and possums increased.  These predators eat reptile eggs and put a big dent in the population of 17 endangered and threatened species of reptiles, including rare sea turtles.  Pythons help control the numbers of raccoons and possums, helping increase the nesting success of endangered reptiles.  Pythons are beneficial for twice as many endangered species than ones they might prey upon.

Scientists’ estimates of Burmese pythons populations in Florida are not based on scientific data.  They are wild guesses bordering on fantasy.  The oft-cited number of 30,000-150,000 is a wild overstimate.  Over the past 12 years, 2000 pythons have been removed from Everglades National Park.  That’s less than 200 per year–nowhere near what one would expect, if there were 30,000 large snakes slithering inside the park.  Last year, there was a python round up.  For a month 1500 snake hunters looked for Burmese pythons to kill.  They netted just 50.  This is strong evidence Burmese pythons are not even close to being as abundant as researchers claim.

Reference:

Dorcas, Michael; et. al.

“Severe Mammal Declines Coincide with Proliferation of Invasive Burmese Pythons in Everglades National Park”

PNAS December 2011

Unnamed author

“Commentary on Mammal Declines in Everglades National Park”

Florida Fish and Wildlife Conservation Commission report 2012

Every organism that ever evolved became an invasive species.  It colonized new territory where it previously had not existed.  The concept of an invasive species that is harmful to the environment is a construct invented by man, the most environmentally damaging species to ever evolve.  The Homo sapien is such an hypocritical species.  The biogeographical history of the earth is a tale of species invading new territories.  The Bering Landbridge allowed a back and forth migration between Eurasia and North America, and the emergence of Central America offered a highway for another interchange of flora and fauna.  Man, the ultimate invader, has facilitated and accelerated the transfer of many species. Environmentalists focus on the harmful results invasive species wreak on ecology but ignore the obvious benefits that may in most cases outweigh the damage.  I mentioned 1 example on my blog last week–Burmese pythons reduce the population of predators that prey on endangered sea turtle eggs.  A recent study (referenced below) gives many more examples of beneficial invasive species that according to the authors of that study should be referred to as “recently arrived species.”

–The honeybee is not native to North America, yet without this “recently arrived species” industrial scale fruit and nut orchards would not be economically viable.

–Environmentalists mistakenly thought non native tamarisk trees were causing low water levels on the Colorado River floodplains.  Millions of dollars were spent eradicating this species.  But later studies showed tamarisk trees were not responsible for causing these low water levels.  Their misguided policy greatly reduced nesting habitat for the endangered willow flycatcher, a species that uses tamarisk in lieu of willow.

Endangered southwestern willow flycatcher’s nest in a non-native tamarisk tree.  The government and groups like the Nature Conservancy spent millions eradicating this species of tree based on the false premise that it lowers water levels.  Now this rare bird has far less nesting habitat.

–Native trees can’t be re-established on eroded Puerto Rican forestlands unless non-native trees are planted first.  With the help of non-native trees, 20 species of native trees were able to grow on badly eroded soils.

–The presence of non native honeysuckle vines increases the population of robins and catbirds that feed on the berries.  The increased bird populations acted as dispersers that helped increase native honeysuckle vine abundance.

–Non native guavas in Kenya helped increase the population of fruit-eating birds there.

–Non native grasses planted on reclaimed strip mines increased the population of endangered Henslow’s sparrows.

–Non native shad serve as forage to help feed  Pacific salmon.

–Non native mussels serve as food for raccoons.

–Butterflies utilize non native species as sources of food.

–Non native cattle maintain early successional habitat, thus helping native species dependent upon this habitat.  They’re a substitute for extinct Pleistocene megafauna.

–African honeybees traverse the areas between fragmented forests in Brazil, aiding the pollination of plant species that could become inbred and sterile.

Some regions provide refuge for species that are endangered in their land of origin.  The Aldabra tortoise is native to a Seychelles Island but is more common in Mauritia where it occupies the ecological role of a now extinct species of giant tortoise.

The Aldabra giant tortoise has been introduced to the island of Mauritia where another species of giant tortoise was overhunted into extinction centuries ago.  It serves as an important disperser of native plants.

Banteng, an endangered species of cattle native to southern Asia, breeds successfully in northern Australia.

Banteng cattle face extinction in their homeland but have successfully established a wild breeding population in northern Australia.

Hippos (imported by a rich cocaine baron) thrive in Colombia.  Game ranches in Texas are the best hope for breeding black rhinos, currently extinct in Africa.

Recently arrived species can cause the extinction of competing native species, but they can also instigate the evolution of new species.  Non native house sparrows appear to be speciating in North America, according to the geographic region they have colonized.  Desert populations of house sparrows have distinct physical characteristics from those found in eastern woodlands.  A new species of honeysuckle fly exists today, thanks to non native honeysuckle vines.  This species resulted from the hybridization of 2 closely related flies that hosted 2 different species of native honeysuckles.  The 2 different species of fly both hosted non native honeysuckles, explaining how they began breeding with each other.

The lonicera fly is the result of hybridization between 2 different species: Rhagoletes menax X R. zephyra.  This new species resulted from the introduction of non native honeysuckles.

The authors of the below referenced study suggest recently arrived species should be more carefully evaluated and managed and not blindly eradicated, simply because they are non native.

Reference:

Schlaepfer, Martin; Dow Sax and Julian Olde

“The Potential Conservation Value of Non-Native Species”

Conservation Biology 25 (3) June 2011

If I could bring just 1 species of the extinct Pleistocene megafauna back to life, it would be Eremotherium laurillardi, an enormous ground sloth that ranged from tropical South America to the warm coastal regions of southeastern North America during warm climate phases.  Although artists always depict all ground sloths as heavily furred beasts, scientists aren’t so certain about Eremotherium.  Some ground sloths undoubtedly were heavily furred–the mummified remains of 1 species found in a cave did have fur.  But this particular species was found in a colder region of South America.  Tropical species of large ground sloths may have been lightly haired like modern warm climate megafauna such as elephants, rhinos, hippos, and humans.  The difference between Eremotherium and Jefferson’s ground sloth (which ranged as far north as Alaska) might have been comparable to the difference between an African elephant and a woolly mammoth. The megatheridae, the extinct family of really big ground sloths, were closely related to the megalonychidae family which has 1 surviving genera of sloths.  There are 2 species in this genus–Linnaeus’s tree sloth (Choloepus didactlylus) and Hoffman’s tree sloth (C. hoffmanni).  They are mistakenly referred to as 2-toed sloths, but they actually have 2 fingers and 3 toes.  Algae grows on their fur, so they are well camouflaged in the evergreen canopy of tropical forests.  They are also closely related to the dwarf ground sloths that colonized Caribbean Islands and lived there until about 4000 years ago.

Hoffman’s tree sloth is closely related to  the Megatherium and Eremotherium ground sloths.

Oddly enough, anatomical and genetic studies suggest the only other surviving genus of tree sloths is not closely related to Chonoepus sloths or any known species of ground sloth.  The Bradypus genus of tree sloths is considered a “sister taxon” of all other sloths.  Despite the similarity in appearance and habitat adaptations, sloths in the Bradypus genus evolved from a different lineage than Chonoepus sloths.  Both genera evolved their arboreal adaptations independently–an incredible example of convergence.  Most intact jungle ecosystems in South America have 1 species of each genera living in the tree tops.

The largest flying bird known to science was the giant teratorn, an extinct condor that lived in South America during the Miocene over 5 million years ago.  It had a wingspan of 21 feet and weighed an astonishing 155 pounds.  It inhabited the Andean Mountains and dry flat pampas, but fossils from this era are rare, and we don’t really know the full extent of its range.  A bird of this size likely had a long lifespan of 50-100 years.  Scientists disagree about its dietary habits.  Some think it was an active predator, swallowing relatively small prey whole because its beak was not built for tearing open large carcasses with tough hides.  However, others believe it was mostly a scavenger because a bird of this size would require 20 pounds of meat per day, and it’s unlikely consuming small animals could satisfy this appetite.  I agree with the latter speculation, though the teratorn may have ingested small animals, if given the opportunity.  It was related to storks and New World vultures, both of which are opportunistic feeders.

Size comparison between the largest flying bird known to science and a school bus.

Specimens of the giant teratorn are only known from 4 localities in South America.  Scientists are interested in figuring out how such a large heavy bird could fly, but the amount of fossil material available from this species is meager, making it difficult to determine this from the few bones they have.  Happily for them, there is abundant fossil material of the closely related North American teratorn–Teratornis merriami. Over 100 specimens of this late Pleistocene species have been excavated from the Rancho la brea tar pits in California.  Additional fossil specimens of North American teratorns have been found in Arizona, Nevada, Florida, and New York.  It had a continent wide distribution but probably occurred in low numbers–a slow breeding yet long-lived species.  T. merriami had a wingspan of 11 feet, less than that of its South American cousin, but still impressive.  Nevertheless, the similarity in anatomy between the 2 species allowed scientists to use specimens of T. merriami to determine how the giant teratorn could fly.  Scientists think it had to run downhill against the wind to get airborne.  Then, it could ride rising warm air (thermals) to get high in the sky where it searched for carrion. It was more of a glider than a flyer.  Just a slight slope in the land would have been adequate for a teratorn to get airborne.  Thermals can occur in a very small space, and teratorns could circle inside these quite narrow thermals to attain height.

Diagram from paper referenced below (Chatterjee 2007) showing how the giant terratorn took off and landed.

No extant species of flying birds approach the wingspan and weight of the giant teratorn, but some are almost as big as the late Pleistocene Merriam’s teratorn.  The kari bustard (Ardeotis tardi), a kind of crane, reaches 40 pounds.  The largest turkey (Maleagris gallopavo) ever killed by a hunter weighed 37 pounds.  Dalmatian pelicans (Pelecanus crispus) are heavy flying birds.  The greater albatross (Diomedea exulans) has a wingspan of 11 feet.  This species gets airborne by running into the wind downslope from the top of waves, much like the extinct teratorns.  The Andean condor (Vultur gryphus) is the most similar living species to the teratorn.  They are closely related and likely occupy a similar ecological niche.

Andean condor in front of an Homo sapiens.

Video of the extant bird with the longest wingspan–a great albatross.  Note the difficulty they have with take off.

References:

Chatterjee, S.; and R. J. Templin, and K.E. Campbell

“The Aerodynamics of Argentavis; the World’s Largest Flying Bird from the Miocene of Argentina”

PNAS 104 (30) 2007

Palmqvist, Paul; and Sergio Vizcaino

“Ecological and Reproductive Constraints of Body Size in the Gigantic Argentavis magnificens (Aves: Teratornighidae) from the Miocene of Argentina”

Ameghiniana 40 2003

A procyonid (Cyonasaura) was among the first North American mammals that island-hopped to South America before a landbridge between the 2 continents full emerged. Like its living cousin, the raccoon, the cyonosaura was attracted to aquatic environments, thus explaining how, perchance, it found its way across islands to South America.  An ecological niche for a bear-sized omnivore was available on this continent, so cyonasaura evolved into chapmalania, a beast that was really just a giant raccoon.  There were few carnivores capable of stopping chapmalania from muscling in on a carcass here then.  Scientists have discovered evidence chapmalania scavenged a dead glyptodont–teeth marks on 1 individual fossil exactly match those of the giant raccoon.  However, chapmalania probably had a varied diet that included plant matter and aquatic organisms.  Chapmalania lived during the Pliocene from 5 million years BP-1.9 million years BP. Bears finally made it to South America at the end of the Pliocene, and they eventually occupied chapmalania’s ecological niche.  They probably outcompeted and replaced them.

Size comparison between the giant raccoon, a human, and a Volkswagon.

Although chapmalania became extinct, there are still at least 17 living species of procyonids.  The most familiar are the abundant North American raccoon (Procyon lotor), and the crab-eating raccoon (P. cancrivan) of South America.  The pygmy raccoon (P. pygmaeus) is restricted to the Cozumel Island off the Yucatan peninsula of Mexico.  This island has been isolated from the mainland for 100,000 years, and genetic studies suggest the Cozumel raccoon diverged from its ancestral population about 60,000 years ago.

The pygmy raccoon of Cozumel Island off the coast of Yucatan.  They differ from more familiar raccoons in their smaller size and golden ringed tails.

There are 4 species of coatimundis.  The white-nosed coatimundi (Nasua naria) ranges throughout Mexica and as far north as Arizona.  N. nasua lives in the tropical jungles of South America, while the other 2 species of coatimundis are restricted to cloud forests there.

White-nosed coatimundi, an inhabitant of Mexican deserts.

The ringtail (Bassariscus astutus) inhabits rocky arid habitats throughout Mexico and as far north as Oregon and as far east as Kansas.  They’re known as miner’s cats because they tamed easily and lived in miner’s cabins where they kept mice populations low.  A new species of ringtail (B sumichasti) was discovered in 2013.

Ringtails.  Another procyonid that prefers arid habitat.

The kinkajou (Potus flavus) and olingos (Bassaricyon sps.) inhabit the canopies of tropical forests where they subsist on fruit and insects.

The kinkajou lives in tropical forest canopies.

The woods look drab this time of year in Georgia, even for a naturalist like me.  I satisfied my hunger for the natural world by visiting the Buford Highway Farmer’s Market instead of taking a stroll through a winter-dulled park.  Most people don’t think about this when they go grocery shopping, but every vegetable, fruit, and animal product in the store descends from a species that lived during the Pleistocene.  The stories behind the origins of each could fill volumes of history, but I’m just going to focus on a couple I noticed on this visit.

The Buford Highway Farmer’s Market in Doraville (a suburb swallowed by Atlanta’s suburban sprawl).  It was featured on Andrew Zimmern’s series Bizarre Foods.

The Buford Highway Farmer’s Market is located in Doraville, Georgia; a former suburb of Atlanta that’s been engulfed by that city’s sprawl.  The store is just off the I-285 bypass at Exit 32.  The produce section is enormous with high quality fruits and vegetables from around the world.

The produce section is huge.  This is just half of it.

There were some items I’d never seen before including white immature coconuts, spiny chayotes, and fresh jackfruit. The size of the jackfruit (Artocarpus heterophyllus) surprised me.  They look like a fruit for a giant species of megafauna, and indeed elephants do feed on them.  The jackfruit belongs to the same family as mulberries and figs.  I didn’t purchase any because 1 jackfruit could feed a family of 20.  I have eaten canned and dried jackfruit.  They are very sweet and have a texture similar to pineapple but the taste is unique.  Jackfruit is native to the tropical forests of southwestern India, but man has spread them throughout tropical Asia, Africa, and Brazil.  Jackfruit trees grow wild as an invasive species in Brazil where coatimundi and monkey populations have benefited from the abundant new source of fruit.  The coatimundis and monkeys also eat birds’ eggs, so bird populations decline in Brazilian jackfruit forests.  Jackfruits have been cultivated for thousands of years–nobody knows exactly when they were first deliberately planted by man.

Jackfruit is as large or larger than watermelon.  Looks like just the right size for an elephant.

Here’s video of an elephant eating jackfruit in India.

This is the first time I’d ever seen white coconuts.

Beyond the amazing produce aisle, the store is divided into ethnic sections–Mexican, Eastern European, American, Indian, Chinese, Japanese, Korean, etc.  I found some delicious kimchi in the Korean wing of the store.  Kimchi is the national condiment of Korea made from fermented napa cabbage, daikon (a long radish), green onions, red hot peppers, ginger, fish sauce, and salt.  I love it.  Kimchi has been made for thousands of years but 1 important ingredient–red pepper–wasn’t used until its introduction to the region in 1598.  Napa cabbage (Brassica rapa Pekinese) is not actually a cabbage (Brassica oleracea) but rather a turnip bred for the luscious stem and leaves instead of the root.  The same holds true for bok choy (B. rapa. chinensis).  The brassica family also includes mustards.  Brassica pollen is often found in Pleistocene-aged pollen samples.  During the Ice Ages wild cabbage, turnip, and mustard grew in temperate region wet meadows.

These are some of the goodies I purchased.  Honey which ironically is from an apiary in Waynesboro 30 minutes from my house, sweet potato chips, cod liver in a can from Norway, and kimchi imported from Korea.    The kimchi is so good it sent me into ecstasy not unlike the look on the face of Freddie King  (on the cd cover below the canned cod liver).  He is one of the greatest electric guitar players of all time.

The flavor of kimchi depends upon a fermenting bacteria known as Lactobacillus kimchii.  This is not unusual–cheese and sourdough bread require fermenting bacteria to give them flavor.  I like to mix kimchi with cream cheese and eat it on crackers.  The spicy acidity of the kimchi plays well with the rich fat of the cream cheese.  The flavor of kimchi varies with its region of origin.  I’ve had some so salty I considered it inedible but the brand in the above photo is excellent.  I’ve also made my own from vegetables I grew in my garden including napa cabbage, turnip, and hot red peppers.  I added ginger and salt. It was good and got even better when I let it sit in the refrigerator for a couple of weeks to develop the funky flavor.

The only unusual food I purchased was canned cod liver imported from Norway.  I’ve never eaten fish liver before.  I’m planning on breading and frying it.  I’m not afraid of fish organs.

Organisms with disjunct range distributions fascinate me because they provide clues about past natural environments.  Direct evidence of past landscapes is rare–over 99% of potential fossil evidence has vanished without being preserved in any way.  The existence of extant species with odd distributions helps fill in gaps in our knowledge of natural history, though it requires some uncertain speculation. The sand myrtle is 1 of many species with an interesting disjunct  range distribution.  This member of the heath family (rhododendrons and blueberries) is found in the sandhills of southern New Jersey; the mountains of northeastern Georgia, eastern Tennessee, and western North Carolina; the sandhills of North Carolina’s coastal plain, and some isolated monadnocks in the upper South Carolina piedmont.

A sand myrtle in full bloom.  They are a short plant, growing to just 20 inches in height.  They can’t grow under tree canopies.

Here’s a link to an excellent range map of the sand myrtle. ( http://www.herbarium.unc.edu/seflora/species.htm?species=Kalmia buxifolia ) In regions where the sand myrtle grows, it is considered rare or uncommon.

One is left to wonder why the sand myrtle disappeared from or doesn’t occur in the areas between its disjunct populations.  One hypothesis could be that it reached suitable habitat through seed transport via bird droppings.  But the great distances between disjunct populations precludes this possibility.  The seeds, if they even stayed viable within the bird’s digestive system, would be excreted long before they reached the other territories.  Wind distribution is a more viable hypothesis.  Winds carry insects, pollen, and light seeds great distances, and this light organic material eventually settles.  Still, this seems an unlikely explanation because sand myrtle should occasionally be found growing in areas between their current distribution, even if the habitat is unsuitable.  The most likely hypothesis requires a bit more complicated explanation.  Sand myrtle may have existed throughout the entire region during the dry climatic phase of the late Pliocene/early Pleistocene.  Today, sand myrtle favors open sunny conditions on poor rocky or sandy soils.  Arid grasslands expanded when dry climates prevailed in the south.  These dry prairie and scrub habitats were subjected to overgrazing by herds of megafauna, leading to bare soils, especially during droughts.  Windy conditions stripped the top soil.  Sand myrtle was able to grow on these poor soils with little competition from trees.  When climatic conditions changed to a wetter cycle, deciduous forests expanded and outcompeted sand myrtle by shading them.  Grassy savannahs were also unsuitable now because frequent lightning strikes led to more fires.  Sand myrtle is both fire and shade intolerant and can only survive in communities with poor shallow soils where fire is infrequent. This probably explains why sand myrtle is currently found in rocky mountains and sand hills and nowhere else.

A Note on my Cod Liver Experiment

In my last blog entry I reported my visit to the Buford Highway Farmer’s Market.  One of the products I purchased was cod liver in a can.  I had a chance to try it yesterday.  When I opened the can, I was surprised to find that most of the volume was filled with oil rendered down from cooking the liver in the can.  I removed over half of the liver and squirted lemon juice on it.  The first bites tasted like canned tuna, and maybe a little like oysters.  But the texture was very soft.  I started having a hard time accepting such a soft texture, so I ate the rest of this portion on buttered toast.  This soft texture was not unlike that of scrambled eggs.  I’m used to eating scrambled eggs, but I usually put lots of shredded cheddar cheese and smoked chipotle pepper in my eggs, and I also put them on buttered toast.  Even with these additions, I still prefer eating my scrambled eggs with either salsa or brown mushroom gravy.  Eggs are just so bland by themselves.  I debated with myself whether to eat the rest of the cod liver for lunch today, but last night I fed it to the cat.  Instead, I’m going to have a nice salami sandwich.

At least 4 species of storks lived in North America during the Pleistocene.  The wood stork (Mycteria americana), the only surviving species, is nearly absent from the fossil record.  It is known from just 1 fossil site–a tar seep in Cuba.  This fossil specimen was found associated with fossils from 2 other species of stork including Wetmore’s (M. wetmori), a similar species but distinctly larger.  Fossil evidence of Wetmore’s stork has also been excavated from sites in Florida and California, indicating it was a widespread species.  Prior to the discovery that wood storks co-existed with Wetmore’s storks on Cuba, scientists assumed the former didn’t colonize North America until the extinction of the latter at the end of the Pleistocene.  But this discovery casts doubt on that assumption.  Wood storks may have lived in parts of North America where the process of fossilization was uncommon.  There is evidence that 2 species of large owls lived in Georgia during the Pleistocene, but the fossil material is so scant scientists are unable to as yet describe the species.  This demonstrates how incomplete the fossil record can be.

The other species of stork that lived in Cuba then was an unknown and undescribed species in the Ciconia genus.  There are 7 extant species of storks in the Ciconia genus including the well known white stork (Ciconia ciconia), a bird that winters in Africa, summers in Europe, and according to legend, brings babies to awaiting parents.  The maguari stork (C. maguari) ranges throughout South America where flooded grasslands predominate. It’s the only extant American stork in the Ciconia genus.  The extinct asphalt stork (C. maltha) was a North American bird, named for specimens found in the asphalt-like tar pits of California. Fossils of this species have been excavated from 34 sites in Florida, 2 sites in California, 1 site in Idaho, and 1 site in Mexico.  (The Mexican specimen was not conclusively identified.) The sites in Florida date from the early Pliocene to the late Pleistocene.  The asphalt stork, as a species, existed for at least 5 million years and likely occurred over a wide continental range for most of that timespan. Though it was closely related to the white stork, the asphalt stork probably occupied an ecological niche similar to that of the marabou stork (Leptoptilos crumeriferus).

Maguari stork  (Ciconia maguari) of South America

Video of marabou storks sharing a carcass with African vultures. Note the featherless head and neck.  This prevents contamination from toxic bacteria on the rotting meat they eat.

Video of marabou storks vs. a pack of mongoose.

The marabou stork scavenges and hunts the African plains but nests in woodlands.  They catch and eat small mammals, bird nestlings, reptiles and amphibians, and insects.  They also rely on carrion, garbage, and even feces.  They often follow vultures, waiting for them to tear open the carcasses before taking advantage of the meal. Stork bills are incapable of opening tough hides.  Species closely related to Old World vultures lived in North America during the Pleistocene.  The asphalt stork likely followed vultures and scavenged in  much the same manner as the marabou stork.  The extinction of North America’s megafauna led to the extinction of avian scavengers including teratorns, Old World vultures, and asphalt storks.

The asphalt stork was a big bird, reaching 4.5 feet tall.  It would have been entertaining to watch scavengers make carcasses disappear during the Pleistocene.  Giant short-faced bears ruled, but if they weren’t around, there would have been battles between coyotes and storks.  With their big bills, storks probably held their own against the smaller canids.

Reference:

Saurez, William

“The Records of Storks (Ciconidae) from Quaternary Asphalt Deposit in Cuba”

The Condor 2003

Ring-billed gulls (Larus delawarensis) often hover over grocery store parking lots in Augusta, Georgia.  The wide open spaces and spilled junk food attract them to these man-made habitats.  They appreciate all the obese Americans who can’t wait to get home to stuff their faces.   The gulls scavenge smashed corn chips and cheese crackers off the pavement.  Gulls perform a valuable service by cleaning up schools of dead fish and mountains of human garbage.  This helps reduce the spread of toxic bacteria in the environment.

Most people think of sea gulls as shore birds, but ring-billed gulls are quite common inland and some may never see the ocean.  Other species of gulls, such as Bonaparte’s (L. philadelphia), follow rivers upstream and can also be found inland.

Ring-billed gulls are commonly found in parking lots and landfills during winter time in Georgia.

Several species of gulls, including the laughing (L. atricilla) and Franklin’s (L. pipiyan), are primarily shore dwellers and do nest off the coast of southeastern states.  The laughing gull prefers to nest in beach thickets, though many species of gulls and terns will lay their eggs in the open.  Sea gull nestlings are mobile shortly after hatching, so they can avoid predation at an early age.

There are at least 5 species of gulls that have a polar distribution.  I hypothesize some or all of these species ranged as far south as what today is South Carolina and Georgia during the Ice Ages.  Glaucous gulls (L. hyperboreus) are a polar species that prefers nesting on rocky sea cliffs where they can feast upon nestlings of other cliff-nesting sea birds.  Today, there are no sea cliffs off the coast of southern states.  But for about 40,000 years, there was an enormous sea cliff, known as Bulls Scarp, off the coast of South Carolina where glaucous gulls could have nested. (See: https://markgelbart.wordpress.com/2014/08/14/bulls-scarp/)  About 13,000 years ago, rising sea level submerged these cliffs, and glaucous gulls likely left the region then.

Glaucous gull.  This is a polar species occasionally found as far south as Virginia.  During the Ice Age it likely ranged much farther south than it does today and it probably nested on Bulls Scarp, a now submerged sea cliff.

Some paleontologists puzzle over how rare gulls are in Pleistocene fossil sites.  The La Brea tar pits preserved the bones of more than an hundred species of birds but have yielded just 1 gull specimen.  I think I know why gull remains appear so rarely in Pleistocene fossil sites.  Pleistocene shorelines are submerged today. Most fossil evidence of gulls is deep beneath the surface of the ocean.

I am unaware of any extinct species of Pleistocene gulls.  The species that are alive today are the same as the ones that lived during the Pleistocene.  However, there were 2 species of Pliocene gulls that are now extinct.  Fossils of L. lacus and L. perpetis were among bird fossils found at a site on the Florida gulf coast.  The fossils are estimated to be between 2 and 2.4 million years old.  Apparently, all the birds found at this site were killed by a toxic red tide.  (I may do a blog article about this site, if I can ever obtain a reasonably priced copy of the scientific paper documenting it.)

The Larus genus originated in the North Atlantic polar region about 20 million years ago.  Sea gulls have dispersed and have an almost worldwide distribution today.

I wrote about the Vero Beach mammoth engraving in February of 2012 (See: https://markgelbart.wordpress.com/2012/02/19/the-vero-beach-mammoth-engraving/).  A fossil collector found the bone of an unidentified species of megafauna engraved with the likeness of a mammoth.  This rare artifact was discovered at the Vero Beach fossil site in Florida.  This site was first excavated about 100 years ago.  Human remains were found in the same strata as the remains of extinct Pleistocene megafauna including sabertooth, mastodon, llama, tapir, etc.  The leading archaeologist of the day insisted humans didn’t colonize North America until after the Pleistocene megafauna became extinct.  He believed Indians buried dead members of their tribe, thus explaining why these particular human remains appeared to be in the same strata as the extinct mammals. Years later, overwhelming evidence showed that humans did overlap in time with North America’s extinct megafauna.  However, I had read that no scientist had been able to test the Vero Beach remains because they had been lost.  Either the Vero Beach remains were rediscovered or they were never lost because I came across a recent study in the Journal of Vertebrate Paleontology that did involve testing these specimens.

Paleoindians hunting.  An analysis of rare earth element concentrations confirms human fossils found at the Vero Beach Site were the same age as the megafauna fossils, solving a century old controversy.

The scientists who published this study (referenced below) analyzed the concentrations of rare earth elements to determine humans lived at Vero Beach at the same time as the extinct Pleistocene megafauna.  (Vero Beach was far inland then and not actually a beach.)  The concentration of rare earth elements in ground water varies over time.  Organisms drink this water and the amount of rare earth elements in their bone matches that of the environment at the time they lived.  The human remains had rare earth element concentrations in the same ratio as the Pleistocene mammals.  These levels are higher than are found in modern Floridian mammals.  This evidence resolves a century old scientific dispute, though few modern scientists doubted the Indian remains dated to the Pleistocene.

Reference:

Macfadden, Bruce; and Barbara Purdy, F. Church, and Thomas Stafford

“Humans were contemporaneous with Late Pleistocene Mammals in Florida: Evidence from Rare Earth Elemental Analysis”

Journal of Vertebrate Paleontology 32 (3) May 2012

Warning: I’m standing on my soap box today.  This blog article might offend Christians, Jews, Muslims, mentally disabled people, the LGBT community, and Native Americans.

I was having a hard time understanding a recent news report on National Public Radio.  The story was about opposition to the execution of a mentally disabled man in Georgia.  I couldn’t figure out what the hell mentally disabled meant.  When I think of the disabled, I think of someone like my wife who can’t walk.  Finally, I remembered mentally disabled was the politically correct term for retarded.  Politically correct fascists have declared the word, retarded, to be offensive and derogatory.  I don’t understand how calling someone mentally disabled could be any less offensive than referring to them as retarded.  Public figures are so afraid now of offending certain groups of people they use confusing terms that just muddy communication.  Another example is the ban of the word, queer.  Instead, the accepted term is LGBT, even though that isn’t any more clear than using the word, queer.  A person listening to a  news report about LGBT people doesn’t know whether the reporter means the L, the G, the B, or the T.  Aren’t the L and the G redundant anyway?  Clarity in language doesn’t matter anymore, just as long as no one is offended.

Scientists are usually among the most enlightened members of society and fear offending people more than most.  This is a shame.  Half of Americans reject the fundamental basis of biological science because it interferes with the narrative of their Sunday school bible stories.  I wish that just once, a prominent scientist would stand up and publicly declare that the bible is full of shit.  People believe the bible is a holy sacred work.  It is not.  It was written thousands of years ago by ignorant fanatics who  favored slavery, oppression of women, and the execution of misbehaving children among many other crimes against humanity.  The God of the bible is pro genocide.  Yes, God told the Israelites to kill every man, woman, child, baby, farm animal, and pet in the town of Jericho.  Christians claim Jesus repudiated the excesses of the Old Testament, but this isn’t true.  In Mathew 5:17 Jesus endorsed all of the Old Testament atrocities when he said, “Do not think I have come to destroy the Law or the Prophets.  I did not come to destroy but to fulfill.”

After the walls of Jericho tumbled down, the Israelites committed genocide, slaughtering men, women, children, farm animals, and pets; all according to God’s orders.  The bible is full of shit like this.  Anyone who considers the bible to be a “holy” book hasn’t really read it.  The bible is for morons.

Mohammed, the founder of Islam, was a mass murderer, an armed robber, a bigamist, and a pedophile.  The Islamic religion was forced upon the Middle East at the point of a sword, just as Christianity was forced upon Europe.  During the Age of Reason secular forces gained control over religion in most of Europe, allowing science and modern progressive values to advance.  If not for this power transfer, western civilization would still be oppressed by a theocracy, not unlike that seen in the Arab region today. Laws in Western countries are no longer written by clerics…for the most part.

Here is an exception. The U.S. Congress passed the Native American Graves and Repatriation Act–a law influenced by religious beliefs.  Indian skeletons and associated artifacts found on government land are supposed to be reburied, according to the stupid superstitions of the tribe that has the closest cultural affiliation to them. Politicians think it is important to show respect for Indian traditions.  I think this law is an impediment to archaeology and historical knowledge.  Scientific data can be lost because the religious beliefs of some idiotic Indians might be offended.

The conflict between science and Native American Indian religious beliefs became apparent in the case of Kennewick man.  The skeleton of a 9500 year old man was discovered along the Columbia River in Washington.  Specimens of humans from this time period in North America are incredibly rare.  Kennewick man was almost a 1 of kind type of discovery, yet the Army Corps of Engineers planned to give the skeleton to a local Indian tribe that was going to bury him without study.  Fortunately, a group of scientists pooled their money together and sued the government for access to the specimen, and several judges ruled in their favor.  Local Indians could not prove they were culturally associated with Kennewick man.  Bill Clinton, the rapist president, ordered the Army Corps of Engineers to bury the site where Kennewick man was found, so scientists couldn’t study the archaeological context, but at least they are allowed to study the skeleton.

Reconstruction of Kennewick Man’s face.  Idiotic Indians wanted to rebury the skeletal remains and prevent archaeologists from studying this extremely rare specimen.

Some Indians believe skeletons are sacred spiritual remains.  This is a really stupid belief.  There probably is no such thing as a spirit, and even if there is, I doubt a spirit would hang around its lifeless remains.  Shouldn’t a spirit be gone to the spirit world?  Physical remains should be unimportant, if there is such a thing as a spirit world.  There just is no logic in the belief that a corpse is sacred.

Alcohol abuse causes 12% of Native American fatalities–4 times the rate of the general population.  Indian babies are born with fetal alcohol spectrum disorder at 7 times the rate of the general population.  39% of Native American women suffer spousal abuse–by far the highest of any ethnic group.  The prevalence of alcoholic wife-beating losers in the Native American population is a  much more serious problem than whether some ancient bones get reburied or whether the Washington Redskins change their name.  Indian protestors need to change their priorities to focus on problems that really matter in this world, rather than the imaginary spirit world.

If Indians are offended by the Washington Redskins, I’ve got the perfect solution for them…Don’t go to any Redskin games, you stupid jerks!

Toxodons and the closely related mixotoxodons originally evolved on the South American continent.  They are classified as notoungulates– primitive hooved animals that resembled the ancient ancestors of cattle, antelope, deer, horses, hogs, etc.  Artistic representations of notonungulates are reminiscent of beasts known from the Eocene and Oligocene.  Mixotoxodons weighed a little over a ton, ate plant material, and looked kind of like a rhino or hippo.

Mixotoxodons were notoungulates, a group of primitive ungulates that evolved in isolation from all other hooved animals when South America was an island continent.

The notoungulates were thought to be restricted to tropical climates.  Until 2004 fossil remains were not known north of Guatemala. But that year, mixotoxodon fossils were excavated from 2 sites in Mexico–Hihiuctilan, Michoacán and La Estribera, Veracruz.  This was a range extension of 900 miles north but still well within the tropics.  During 2012 a mixotoxodon tooth (un upper 3rd left molar) was discovered along Cypress Creek, Harris County, Texas–a further range extension of 800 miles north.

Michoacán Province in Mexico.  Mixotoxodon fossils were found here for the first time about a decade ago.  At the time they were the northernmost known fossils of this species.

Harris County, Texas.  A fossil tooth of a mixotoxodon was found here just a few years ago.  Now this site is the northernmost known locality where toxodons once lived.

Harris County, Texas borders the modern day temperate and subtropical zone.  The mixotoxodon tooth couldn’t be directly dated but 2 pieces of fossil oak wood located 10 meters upstream from the specimen were dated and yielded ages of 17,080 years BP and 23,780 years BP.  The tooth is believed to be from the same geological strata as the fossil wood.  If the tooth does belong within this time span, than mixotoxodons occurred in southeast Texas during the Last Glacial Maximum, the coldest phase of the last Ice Age.  However, climate in this region then was likely similar to that of the present day, though summers were probably a bit cooler and winters a little warmer.  The modern day oceanic gulf stream that moderates present day climates in eastern North America didn’t exist during the coldest phases of the Ice Age.  Instead, tropically heated water remained near the equator and may have upwelled into the Gulf of Mexico at times.  When this warm water circulated just a little north, it may have reduced the intensity and frequency of frosts near the southern Atlantic coast and around the coast along the Gulf of Mexico.  The extent of warm water upwelling in this region likely fluctuated cyclically, resulting in decades of warm winters with few local frosts alternating with decades when frosts occurred more often because the warm waters pooled near the equator and away from nearby coasts.

I see no ecological reason why mixotoxodons couldn’t have occurred further east in North America.  Coastal savannah interspersed with open woodlands along waterways stretched from Mexico to Florida.  The Harris County mixotoxodon tooth was found right in the middle of where this type of environment existed.  Why isn’t there more evidence of mixotoxodons in North America, especially from the abundant fossil sites in Florida?  The fossil record is not a complete accounting of every organism that ever lived in a location, perhaps explaining the absence of this species.  Collared peccaries and giant short-faced bears were unknown from Florida’s fossil record until just a few years ago, so maybe some day someone will find a mixotoxodon fossil elsewhere in the south.  Alternatively, the Harris County specimen may represent a very temporary range extension of a cold sensitive species that occurred during a few decades or centuries when an upwelling of tropically warmed water resulted in a brief cycle of locally frost free winters.

Below is a list of currently known land mammals, weighing over 100 pounds, that lived in southeastern North America during the late Pleistocene.

1. Mixotoxodon (Mixotoxodon cf larensis)–from just 1 tooth certain species identification is not possible

2. Columbian mammoth (Mammuthus colombi)

3. woolly mammoth (Mammuthus primigenius)–not known farther south than Virginia

4. mastodon (Mammut americanum)

5. gompothere (Cuverionius tropicalis)

6. upland bison (Bison antiquus)

7. long-horned bison (Bison latifrons)

8. helmeted musk ox (Bootherium bombifrons)

9. collared peccary (Pecari tajadu)

10. long-nosed peccary (Mylohyus nasatus)

11. flat-headed peccary (Platygonus compressus)

13. stout-legged llama (Paleolama mirifica)

14. long -necked llama (Hemiauchenia macrophela)

15. stag-moose (Cervalces scotti)–from a site in South Carolina and a site in Mississippi

16. elk (Cervus canadensis)

17. caribou (Rangifer tarandus)

18. white tailed deer (Odocoilus virginiana)

19. horse (Equus ?)

20. half-ass (Equus?)

21. Vero tapir (Tapirus veroensis)

22. giant ground sloth (Eremotherium laurillardi)

23. Harlan’s ground sloth (Paramylodon harlani)

24. Jefferson’s ground sloth (Megalonyx jeffersonii)

25. pampathere (Holmesima septentrionalis)

26. glyptodont (Glyptodont floridanum)

27. giant beaver (Casteroides dilophidus)

28. capybara (Hydrochoreus)

29. another species of capybara (Neochoreus)

30. giant short-faced bear (Arctodus simus)

31. spectacled bear (Tremarctos floridanus)

32. black bear (Ursus americanus)

33. dire wolf (Canis dirus)

34. saber-tooth (Smilodon fatalis)

35. scimitar-tooth (Dinobastis serum)

36. giant lion (Panthera atrox)

37. jaguar (Panthera onca)

38. cougar (Puma concolor)

39. human (Homo sapiens)

References:

Lundelius, Ernest; et. al

“The First Occurrence of a Toxodont (Mammalia; Notoungulata) in the U.S.”

Journal of Vertebrate Paleontology 33 (1) Jan 2013

De la Rosa, Ruben; Jose Guzman-Gutierrez and Carlos Hurtado Menoza

“A New Occurrence of Toxodonts in the Pleistocene of Mexico”

Current Research in the Pleistocene 2011

Scientists first described the giant short-faced bear as an unusually long-limbed bruin with a shortened catlike face.  Some proposed this species outran prey, much like a cheetah does.  However, later studies determined it was not a particularly fast runner but was instead built for endurance.  Nevertheless, these descriptions suggested a very bizarre kind of bear.  But now, the most recent and thorough study of the short-faced bear’s anatomy upends much of what was previously thought about this bear. Paleontologists, led by Borja Figuerida, compared skeletons of the giant short-faced bear with those of 56 different species of carnivores including all living species of bear.  In all they looked at 411 specimens.  They believe the giant short-faced bear did not sport much of a different appearance than any living species of bear, though it was very large. The legs were not unusually long.  They claim the assumption of a bear with unusually long limbs was a misinterpretation based on an optical illusion.  Bears have short backs compared to big cats and wolves, leading previous researchers to overestimate the length of this bear’s legs.  Moreover, its snout was no shorter in proportion than those of the Malaysian sun bear (Helarctos malayanus) and the spectacled bear (Tremarctos ornatus).

The giant short-faced bear’s legs were not as long as typically depicted in illustrations.

Malayan sun bear (Helarctos malayanus).  A study suggests the proportions of the giant short-faced bear’s snout were no different from that of this endangered species.

The frequency of supersized individuals in the population of giant short-faced bears surprised the scientists involved in this study.  The male bear skeletons they studied came from individuals that frequently reached an estimated weight of 2000 pounds.  (Specimens from Alaska and the Yukon tended to be the largest.)  There was great sexual dimorphism–females averaged just an estimated 400-800 pounds.  B. Figuerida and his co-researchers do not think the giant short-faced bear was an hypercarnivore that chased down prey or lived entirely from scavenging.  Instead, they believe it was a generalist feeder like most modern day bears.  This giant bear ate any available plant and animal material in its environment.  Nevertheless, they probably did often scavenge carcasses.  Saber-tooth and scimitar-tooth cats had weak jaw muscles and likely ate just the organs and soft muscle tissues, leaving quite a lot of meat for a huge hungry bear to consume.

Reference: Figuerida, Borja; Juan Perez-Claros, and Vanessa Torregruz

“Demythologizing Arctodus simus, the “Short-Faced” Long Legged and Predaceous Bear that never was”

Journal of Vertebrate Paleontology 30 (1) 2010