The Vero Beach Mammoth Engraving

About 5 years ago James Kennedy, an amateur fossil collector, found a nondescript scrap of bone near Vero Beach, Florida.  It seemed so ordinary he went home and promptly stuck it in a box under his sink.  But a few months later he took it out of the box, cleaned it,  and discovered it was not nondescript at all–there was an engraving of a mammoth on it.  Paleolithic art on portable objects such as bone, antler, and rock are common in Europe but before this discovery unknown in North America.

Up close view of the mammoth engraving.  The domed forehead indicates it depicts a mammoth, not a mastodon.  The fossil is mineralized and has no DNA left for species identification. The whole scrap of bone is just 16 inches long.  The engraving itself is about 4 inches wide. 

This fossil is an incredible and rare find from a site that has produced a bounty of other wonderful fossils and artifacts, including human remains probably dating to about 14,000 calender years BP.  Of course the first thought to cross the minds of scientists when they initially saw the specimen was the possibility that it might be fake.  But there are several ingenius scientific techniques that can detect whether the artifact is a fraud or not.  By analyzing the ratio of rare earth elements found in the specimen (a method I’ve discussed on a couple of previous blog entries including http://markgelbart.wordpress.com/2011/08/28/the-fossil-rich-region-of-tunica-hills-louisiana/) they determined the fossil dates to the Pleistocene and did come from the Vero Beach site.  After examination of the specimen under a microscope, scientists concluded the engraving showed the same amount of weathering as the rest of the bone.  A fresh engraving would look much clearer than the rest of the bone.  Scientists made a fresh incision on this bone, then used a scanning electron microscope to compare the fresh cuts with the older engraved cuts.  The fresh cuts had a “debris field” (microscopic dust) whereas the engraved one didn’t, suggesting an older debris field eroded away.  Also, it looks as if the mineralization of the bone occurred across the engraving.  Scientists conducted 2 additional tests to determine if the engraving was authentic.  Energy dispersion x-ray spectroscopy can detect whether the specimen was cut, then applied with a substance that made it look mineralized.  No substance they could detect was used.  Finally, they made a cast and mold of the fossil and subjected it to reflection transformation imagery (http://vcg.isti.cnr.it/Publications/2006/DCCS06/).  This helped them determine the engraving wasn’t made recently.

James Kennedy with what looks like a bunch of fossils.

I’m convinced it’s authentic.  From examining Mr. Kennedy’s dwelling (his home?) in the above photograph, he appears to be a working class kind of guy and unlikely to be harboring a method that can fool modern forensic scientific techniques.

According to a Mammoth Trumpet article, the Vero Beach mammoth engraving is being auctioned.  If a museum doesn’t place the highest bid, this specimen could be lost to science.

The whole scrap of bone with the engraving on it.  Geometric designs extended past the broken end. The size of the bone narrows it down to either mammoth, mastodon, or giant sloth.  Not enough is left for scientists to determine which it was.  But without a doubt the engraving depicts a mammoth.  Mammoths had  domed forehead, mastodons didn’t.  If I had to make a bet, I’d gamble the bone is from a mammoth because it’s likely the paleo-indian who engraved it was drawing the animal it was from.

Vero Man was NOT a 12 Foot Tall Giant

While researching the topic of this blog entry, I came across a creationist blogger who claimed the scientists who originally examined the fossils from the Vero Beach excavation found bones of 12 foot tall men.  Supposedly, this supported the existence of giants as recorded in biblical accounts.  I knew this was bullshit, but the creationist had a source–a newspaper article written in 1930.  I assumed the newspaper reporter was probably a sensationalist idiot, incapable of distinguishing his ass from a hole in the ground. I was certain the reporter had never even read the original scientific paper and had gotten his facts confused.  I’ve read hundreds of scientific papers on paleontological discoveries, and scientists always give exact measurements of every single body part when they find something new and different.  So I searched and found the article written by E.H. Sellards in 1916, and much to my delight, it was available for free online.

It’s an excellent paper, quite advanced for its time–realize that in 1915 when workers were digging  the drainage canal that led to the abundant  fossil discoveries here, north Florida was a wilderness with a few subsistence farmers, cotton plantations, and lumber operations.  The canal construction bisected an extinct river bed that formerly flowed into the Indian River lagoon.  The extinct river was about 100 yards across but was shallow.  I suspect it was a kind of brackish stream.  Workers kept finding cartloads of Pleistocene-age fossils, attracting the attention of E. H. Sellards, a geologist, and O. Hays, a vertebrate zoologist.  Dr. Sellards told the workers to look for human remains, though he didn’t expect them to find any because at the time conventional wisdom assumed that Pleistocene mammal extinctions in North America occurred before man’s arrival on the continent.  Much to his surprise, workers and fossil collectors did find human remains in 3 different places along the canal, and human artifacts in 2 additional spots–all associated in the same strata with bones of Pleistocene-age mammals.  This was the first evidence ever that humans co-existed with extinct Pleistocene mammals in North America.  In total they found the remains of at least 5 individual people.

The human specimens from the first locality included leg, heel, feet, and finger bones.  They were found associated with fossils of mammoths, mastodons, horses, deer, and Jefferson’s ground sloth.  The mammal fossils had the same degree of mineralization as the human fossils.

The human specimens from the second locality consisted of ankle, pubic, and finger bones and were found with 7 flint tools.  I’m no expert on lithics, but from the pictures in Dr. Sellards’ paper, they look like scrapers used to scrape fur from hides.  These specimens and artifacts were found associated with fossils of mammoth, horse, tapir, possum, rabbit, cotton rat, armadillo, shrew, alligator, snakes, and acorns.  Lots of good plant fossils were initially discovered, but after exposure to air overnight, all but the acorns, turned to dust.  Dr. Sellards could have used the benefit of modern techniques to prevent this.

The human specimens from the third locality included arm, shoulder, jaw, foot, tooth, toe, and skull bones along with broken pottery, bone implements, and flint arrowheads.

Dr. Sellards also found mammoth and bird bones with human-made engravings.  These were found associated with fossils of horse, saber-tooth, deer, tapir, horse, rabbit, round-tailed muskrat, raccoon, alligator, snake, fish, amphibian, bird, acorns, and wood.

Dr. Sellards wrote “Undisturbed strata over human bones precluded the possiblity of human grave burial intruding into the sediment.”  He even found a heavy rock over some of the human bones.  Moreover, if these were more recent purposeful graves, more of the skeletons would have been found rather than just disarticulated pieces.  Despite Dr. Sellards’ sound reasoning, Ales Hrudlicka, the leading American anthropologist then, insisted these bones were from later Indian burials intruding into the older fossil deposit.  This controversy occurred before the invention of carbon dating which would have settled the issue.  Dr. Hrudlicka refused to believe Indians co-existed with now extinct Pleistocene mammals, even after discovery of Clovis arrowheads in mammoth bones in 1932.  Comically, he once gave a lecture denying this possibility, immediately following presentation of the famous Clovis evidence at a symposium. Some people are just so close-minded, they can’t accept evidence, even after it slaps them upside the head.  Which brings me back to the creationist.

In Dr. Sellards paper he only gives measurements for 1 of the human specimens.  He measured “the lower margin of the lesser tuberosity to the upper margin of the inner condylur on the femur.”  It was 29 cm.  On an average modern human that part of the leg is 32 cm.  So if anything, that particular Indian was smaller than average–not a 12 foot giant as the full-of-shit journalist reported in his article in 1930.  The creationist blogger should have taken the effort to do some critical thinking and deeper research before he regurgitated phony bullshit.

For a century now this drainage canal in Vero Beach has been a productive site for amateur fossil collectors.  In addition to species mentioned above, they’ve found fossils of dire wolves, jaguars, bobcats, llamas, bison, pampatheres (a 300 pound armadillo), and Eremotherium–a really giant ground sloth.  But this will soon be coming to an end.  The city of Vero Beach is planning to cover the canal in concrete and turn it into a sewage outlet, though they are giving scientists extra time to do some last minute collecting before they close this door to the past.

Incidentally, all the human remains from the Vero Beach fossil site were lost.  After their discovery the specimens were shuttled back and forth between the Smithsonian Insitution and Florida State, but by 1947 interested parties lost all track of them.  What a shame.

References:

Lepper, Bradley

“Mammoth Engraved on Bone from Florida”

Mammoth Trumpet (27) 1 January 2012

Sellards, E.H.

“Human Remains and Associated Fauna from the Pleistocene of Florida”

Florida State Geological Survey 1916

It’s Ice Cream for Deer but Poison for Humans

One of the dumbest examples of wilderness survival folklore ever espoused is the notion that to determine whether a potentially edible plant is poisonous or not, a person should observe an animal consuming the plant.  The logical fallacy is the assumption that if the animal could eat the plant and not die, than it would be safe for humans to eat.  This is a stupid assumption for 2 reasons:  First, the animal could crawl off in the bushes and die later out of sight.  Second, and more importantly, all animals have completely different physiologies than humans.  There are many plants highly poisonous to humans but perfectly edible to many species of mammals, birds, and especially insects, such as caterpillars which consume poisonous plants that make them inedible to birds when the caterpillars become butterflies.  Below are 2 species of common plants found in Georgia that are favorite foods of deer but are poisonous to humans.

Strawberry bush–Euonymous americanus.  Naturalist refer to the plant as “ice cream” for deer.  But it is poisonous to humans.  It’s in the bittersweet family.

Buffalo nut–Pyrularia pubera.  Also a favored deer edible that is poisonous to humans.  It’s in the sandalwood family.

Deer eat strawberry bush twigs, and birds eat the fruits, but both parts are deadly to humans, causing vomiting, diarrhea, irregular hearbeats, convulsions, coma, and death.   Scientists don’t know what type of poison it is.  Strawberry bush is also poisonous to livestock.  It was advantageous for deer to evolve the ability to digest a plant that was likely poisonous to competing herbivores of the Pleistocene, such as bison and horses.  I wonder if other browsing Pleistocene herbivores (mastodons, tapirs, Jefferson’s ground sloths) could also eat strawberry bush without ill effect.  Browsers tend to be more resistant to plant poisons because they eat small amounts of a great variety of foods and don’t concentrate the poison in their systems.  Grazers eat large quantities of fewer species of plants, making it more difficult to evolve the ability to eat toxic vegetation.  Deer probably evolved the capacity to survive eating toxic plants because they only nibbled on the plant, and individuals that could survive eating small quantities passed this characteristic on to the next generation, unlike bison which ate such large quantities that no individuals survived consuming the toxins.   Gradually, each generation of deer had a growing inherited capacity to digest this toxic plant with no ill effects.

Buffalo nut is toxic to humans, rabbits, and pigs, but not deer, cattle, horses, sheep, and mice.  Its poison is an amino acid similar to that found in cobra poison.  The protein stimulates growth hormone in deer and may facilitate antler growth. In addition to harboring plant toxins, buffalo nut is a parasite, living on nutrients from other tree’s roots.  The roots of a buffalo nut “kiss” the roots of other species forming a hausteum, an attachment that helps them leech nutrients absorbed by the other tree. Many species of trees serve as host species for buffalo nut, including oak, chestnut, and hemlock.

Both strawberry bush and buffalo nut grow as understory trees in disturbed moist woodlands–a habitat that expanded during interstadials and interglacials but decreased during stadials.  Grazers always became more abundant during stadials when arid cool climates fostered the growth of grasslands but decreased the abundance of toxic woodland plants.  Browsers increased when forests expanded.  Strawberry bush and buffalo nut are known as “gap phase” species, thriving in areas of the forest disturbed by fire, storm, or human activity.

Like most plants, strawberry bush and buffalo nut are invisible in the Pleistocene fossil record, but they must have been present then or they wouldn’t be here today.

Speaking of (or rather writing of) ice cream for deer, I tried growing fava beans in my garden 2 years ago.  Fava beans are a cold hardy legume.  I read they could survive temperatures as low as 15 degrees F.  Because winters in Augusta, Georgia seldom get that cold, I predicted they would do well.  I had a great stand of fava beans in my backyard by early December.  One afternoon while taking a walk in broad daylight, I saw a deer.  It stopped about 20 yards from where I stood.  It seemed unafraid and even stomped its hooves as if attempting to intimidate me.  I resumed walking up the street until I heard hooves hitting pavement behind me.  I realized it was heading straight for my fava bean patch.  I raced back to scare it away but 2 big dogs came out of nowhere and chased the fleeing deer from my garden for me.  My fava beans were safe but nor for long–a few days later the temperature dropped below 15 degrees, an unfortunate stroke of luck because temps here get that cold maybe once every 10 years.  The favas did sprout back from the roots but production was meager compared to what would have been from the lush first growth.

Freshwater mussels of Georgia

I used to think clams were boring, but that was before I learned about their reproductive life cycle.  I formerly thought of bivalves as inactive organisms that live on aquatic bottoms like a dead stick in the mud.  It’s true most species of freshwater mussels are sedentary life forms, filter-feeding on the microscopic algae and bacteria that are carried their way by currents.  The males and females are even incapable of approaching each other to mate.  Instead, the male ejects sperm into the water and the female takes it in while filter feeding, thus fertilizing her eggs.  Amazingly, the female tricks more advanced creatures into helping spread her larva.  Some species of mussels have a fleshy protuberance that resembles a worm or small minnow.  When a fish strikes at the bait, the female mussel squirts her larva onto the fish’s gills.  Eventually, the larva develop into little mussels and drop to the bottom of a river or lake and burrow into the mud where they’ll probably live for the rest of their lives.  Other species of mussels release bags that resemble myriads of tiny aquatic insects.  A fish striking the bag releases hundreds of larva which attach themselves to the fish’s gills.  Biology majors seeking a subject for a master’s thesis take note–little is known about which mussel species parasitize which fish species, so the field of study is wide open.

Life cycle of a freshwater mussel.

Elliptio complanata–Eastern elliptio.  This widespread freshwater mussel occurs in almost every river system in Georgia.  It’s quite edible.  I’ve never eaten one, but I picked up a dead one not long ago and the inside looked and smelled just like an oyster.  It left a carrion-like odor on my hand, however, indicating it had gone rotten.

The Altamaha Spinymussel–Elliptio spinosa.  This endangered species only inhabits the Altamaha River.

Top: Anodonta grandis–Giant Floater…Bottom: Villosa dumbelis–Eastern Creekshell

Rayed Pink Fatmucket–Lampsilis splendida

Anodonta imbecilis–Paper pondshell

A great variety of mussel species live in Georgia’s waters–the exact number is probably unknown.  There’s an estimated >126 species from at least 16 genera, though many are in danger or have succombed to extinction.  Mussels live a long time–up to 100 years.  Nevertheless, many species are endangered.  Dams, sedimentation, pollution, and the introduction of invasive Asiatic clams and zebra mussels have all reduced the amount of available habitat.  Before Europeans colonized North America mussels were an abundant food source for the Indians.  Georgia’ s rivers used to be crystal clear for most of the year, except during summer when Indians burned the woods, and they became black with ash (a practice they engaged in every year).  Today, Georgia’s rivers are clogged with agriculturally eroded mud.  This is not good for filter-feeders.

Surprisingly, I found no information about Pleistocene-aged freshwater mussels in Georgia on the web.  Mussel shells are as durable as bone and should be present in alluvial fossil sites.  I suspect they’ve been ignored or unnoted because scientists don’t know whether specimens associated with alluvial fossil bones are from the present or the Pleistocene.  Leisey Shell Pit in Florida is a famous fossil site noted for bivalve shells, but these are sea shells, dating to when the site was under ocean water.  Nevertheless, freshwater mussels were certainly abundant in Pleistocene freshwater environments throughout the south.  Most were probably the same species that today are heading for extinction.

My Dream Nature Property (Part 1)

I’m starting a new irregular series on this blog–my dream nature property.  My fantasy of living in Georgia 36,000 BP is not really possible.  Instead, I’ll be wishing and dreaming about properties in rural Georgia that I hope to one day purchase.  I’ll stick a trailer or cabin on the land and live out my days there.  So this fantasy has a possibility of coming true.

The first property I’d like to salivate over as a naturalist is this little gem on a Broad River Bluff.

http://www.landflip.com/land.asp?listing_id=7417

It’s 154 acres of mostly wooded land in the middle of nowhere.  I drove through this area of Wilkes County last spring and summer.  I only stepped out of my car for brief periods of time but saw deer and turkey instantly.  This property is only a few miles upstream from the spectacular Anthony Shoals.   I can imagine a nice canoe or kayak trip back and forth to the shoals. Most of this part of Wilkes County is abandoned farmland that has grown up into second growth forest or overgrown fields.  It’s very quiet and there is little traffic, unlike some of our crowded National Parks and National Forests.

View of the Broad River from this beautiful property.

The property itself is said to consist of a mixture of hardwoods and pines.  A satellite view shows the wooded property is surrounded by hayfields and cow pastures.  This isn’t necessarily a bad thing–open spaces attract grassland and forest edge species.  Hayfields and cow pastures are a lot better than suburbs anyway.  Because of the river, I’d be sure to see a great variety of aquatic animals and birds.  The bluff forest may hold some rare types of plants as well.  It appears the owners use the land for hunting and fishing.  I’d most likely use it for birdwatching, nature walking, and fishing, though, who knows, I might take up hunting as well.

A duck pond on the property.

A nice picnic area for  private beer parties and outdoor grilling or just quiet solitude.  Note the large leaning trees.

The property is selling for $369,668.  I’m going to have to get real lucky on the stock market to be able to afford something like this.  There’s no house on the property, so if I decide to live here, I’d have to pay for that as well.  When considering buying rural land, it’s best to realize how much property taxes will be.  A buyer should understand that not only do they need to come up with the money or credit to purchase the land, but they need to have a lot of money socked away to pay property taxes every year.

I think government should give tax breaks to people who allow their properties to remain natural, especially if they harbor rare environments.  Much of Georgia’s remaining rural land is destined to be ruined by monocultured tree farms and row crops, so the owners can afford to pay property taxes.  They may be more inclined to let it remain wild, if they don’t have to pay property taxes on it.

New Study of Burmese Pythons in South Florida is Ripe for Debunking

The National Academy of Science often publishes some really bad studies.  One example was a paper that proclaimed Ice Age mammal extinction, the Younger Dryas cold phase, and Carolina Bays were all caused by a comet colliding with the Laurentide Glacier 12,900 years ago.  This illogical paper has since been thoroughly debunked.  Another study ripe for debunking is one that made headline news last week. http://www.pnas.org/content/early/2012/01/23/1115226109.full.pdf+html

Scientists claim the populations of medium-sized mammals in Everglades National Park has been reduced by up to 100% since the accidental introduction of Burmese pythons.  I suspect this is alarmist bullshit.  Reptiles have very slow metabolisms and do not eat as much as carnivorous mammals.  Moreover, if an introduced predator reduced its food supply, it in turn would suffer a population decline, because they would have nothing left to eat.  The number of Burmese pythons captured has steadily increased (with the exception of the 2010 when there was a snake-killing hard freeze), suggesting the species is increasing in number.  This increase in python population couldn’t happen, if they were wiping out their prey base.

The method they used to count deer, raccoon, possums, rabbits, bobcats, and foxes is highly questionable and somewhat bizarre.  Scientists drove at night 331 times over an 8 year period in cars with 1-4 people in them, and counted live and road-killed animals within Everglades National Park.  Supposedly, they did the same thing during the 1990′s before Burmese pythons colonized the park, though as far as I know this data wasn’t published then, and they could be pulling numbers out of their ass.

The results confirm (in my opinion) that this study is full of shit.  From 2003-2011 these scientists only counted 9 raccoons and 5 possums.  9 raccoons and 5 possums in 8 years?  No way. No way!  That is 1 raccoon and less than 1 possum per year.  (Why didn’t they count armadilloes?– Another common small mammal in south Florida.)  These results are just not credible.  To get a good estimate of small mammal populations, the scientists should have used live traps which I guarantee would catch raccoons and possums with a high frequency.  I’m certain these animals are still abundant in the park.  In fact a recent series on the Discovery channel featuring a nature park adjacent to the Everglades that is run by the Seminole Indians showed the Indians frequently capturing problem or injured raccoons and bobcats.

The scientists admit they have no direct evidence that snakes are behind the so-called decline in the population of medium-sized mammals in the park, but point to anecdotal evidence.  If all they have is anecdotal evidence, they’ve got nothing.

The introduction of Burmese pythons has been a wonderful addition to an ecosystem that was in desperate need of more large predators.  I have no doubt that the population of medium-sized mammals has been reduced, but there is no way they’ve decreased as much as this ridiculous study claims.  The introduction of Burmese pythons has been highly beneficial for box turtles and birds whose eggs were vulnerable to the overpopulation of raccoons and possums.

By the way, the Everglades is overrated.  The most beautiful and productive ecosystem in Florida was destroyed by Walt Disney.  The creator of Bambi killed more wildlife than a millenia of hunters.  William Bartram and other explorers all agreed that the region now ruined by Disney World and Orlando was the most beautiful wild place they’d ever seen, and this was in the 18th century when just about every place on the continent was wild.

Sagponds Contain a Partial Pollen Record of Ice Age Vegetation in Northwest Georgia

In the southern Appalachian mountains when groundwater dissolves underlying limestone the ground slumps to a granite bottom, creating an interesting environment known as a sagpond.  These differ from sagponds located in California which are formed from strike-slip faults.  Georgia sagponds form from the same geological principle that creates limesink lakes in Florida.  Dr. Charles Wharton counted as many as 96 sagponds per square mile in Bartow County.  They range in size from a few feet across to several acres.  Some go seasonally dry; others retain water year round.  Scientists recognize 4 types of sagponds.  Dry sagponds drain within an hour after rain stops.  Young sagponds, where the ground hasn’t finished slumping, hold water during winter and spring.  Mature sagponds are partially filled with colluvial silt and retain water year round.  Extinct sagponds have been completely filled with silt but still might be moist enough to support a marsh.

Topographical map of Green Pond.  Sagponds often form on mountains and provide wetland habitats in otherwise dry upland environments.

These low wet areas dotting the otherwise dry upland ridge and valley region host disjunct populations of at least 49 species of plants that are normally found on the coastal plain, including the evergreen laurel oak, gallberry (a type of holly), fetterbush, rock rose,  joint grass, panic grass, beaked rush, and many others.  Common aquatic plants found in sagponds are tupelo, buttonbush, red maple, and sedges.  Buttonbush and tupelo tend to grow in the middle of a sagpond; grass and sedge grow on the edges; than there is a heath zone ringed by a lowland woods consisting of loblolly pine, laurel oak, and red maple.

Page from the book Natural Environments of Georgia with a photo of a dry sagpond in Bartow County.

Photo by Alan Cressler of a sagpond on Keel Mountain in Madison County, Alabama.  I couldn’t find any photos on the web of sagponds in Georgia, though there are supposed to be a lot of them.

Dr. Wharton reports that Bloody Pond in Chickamauga Battlefield Park has a large stand of willow oaks.  (While researching this topic, I discovered that there are at least 2 other Civil War era battlefields with areas known as “Bloody Pond.”)

Scientists looking for ancient pollen and Pleistocene-aged plant macrofossils have excavated and cored several sagponds–Bob Black Pond, Quicksand Pond, Green Pond, Pigeon Mountain Marsh, and Lookout Mountain Marsh.  The pollen record from all these sites combined cover a timespan of between ~34,000 Bp-~10,000 BP in calender years.  Some of the studies date to before scientists realized carbon-dating gave dates too young when compared to tree rings.  The data I give in this discussion mention dates I’ve adjusted.  They’re just rough estimates based on the inaccurate dates from the early studies.

Pollen from Green Pond, believed to date to the Farmdalian Interstadial, suggests an environment in northwest Georgia consisting of dry oak and hickory woodlands with prairie openings.  Dr. W. A. Watts (of Penn State but now retired) conducted this study in 1973 and gave carbon dates of 29,630 BP- 25,000 BP which should be adjusted to about 34 ka BP-30 ka BP.  Pine pollen was scarce.  ~28,000 years ago pine and spruce pollen began to increase, indicating an abrupt change to a cooler drier climate.  Surprisingly, pond cypress was locally present.  This shows that individual plant species ranges didn’t always change in predictable patterns.  Pond cypress is absent in this region today, despite a warmer climate.  Shortly after this date, the pond filled with sediment and the pollen record ends for this site.  Conveniently, this is when the pollen record from sediment cored from Bob Black Pond, which Dr. Watts also studied in the early 1970′s, begins. 

Dr. Stephen Jackson of Wyoming University also studied Bob Black Pond over 20 years later.  He found boreal forest species dating to about 22,000 BP.  In addition to pollen he found plant macrofossils of white pine, red pine, jack pine, white spruce, Critchfield’s spruce, and paper birch.  Critchfield’s spruce is an extinct species thought to be adapted to temperate climates, and white pine still grows on the mountains of north Georgia, but the other 4 species no longer range much further south than Canada.

Jack pine present day range map.  This species lived as far south as northwest Georgia during the LGM.  Today, it lives no further south than northern Michigan.  Red pine is restricted to New England.  White spruce lives across Canada as does paper birch.

There’s no doubt the climate in north Georgia during the Last Glacial Maximum was cooler than that of today, but it wasn’t necessarily as cool as present day southern Canada, despite the presence of Canadian species of trees.  Scientists may have originally misinterpeted this data when they assumed the climate here was comparable to today’s southern Canada.  Pine and grass grow better in atmospheres with lower CO2 than broad-leafed trees.  So moderately lower temperatures combined with lower CO2 levels allowed northern species of conifers to compete better with oaks, maples, and other broad-leafed trees for space in the southern Appalachians.  It’s a good thing for the boreal species too because their present day range was completely under miles of ice then.

Fossil pollen from Pigeon Marsh in Walker County dates to approximately the LGM.  Jack and red pine pollen ranges from 25%-45%, oak pollen ranges from 30%-40%, and spruce pollen ranges from 1%-2%.  Hickory and chestnut were present but not abundant.   After the LGM, as the climate remained cool but became more moist, beech became the dominant tree here until the modern floral composition took over.

During the Pleistocene sagponds would’ve been prime foraging grounds for herds of hungry mastodons.  Sagponds supported the kinds of aquatic plants (especially buttonbush and pond cypress) that we know mastodons ate from analysis of their coprolites.  And indeed, fossil evidence of mastodons has been found in the ridge and valley region of Georgia and Tennessee.

References:

Watts, W. A.

“The Vegetation Record of a Mid-Wisconsinian Interstadial in Northwest Georgia”

Quaternary Research 3 (2) 1973

Wharton, Charles

The Natural Environments of Georgia

Georgia Department of Natural Resources 1980

The Eerie Call of the Common Loon (Gavia immer immer)

The call of the loon sounds ghostly.  I imagine the howling of dire wolves and the eerie calling of loons made living in the Pleistocene kind of spooky.  Loons are in the order Gaviformes which is always the first order listed in books about North American birds, meaning they are considered the most primitive avian group living on the continent. Of all the North American birds they must be the closest living relatives of the dinosaurs.  Perhaps some species of dinosaurs had a smilar vocalization.  Below is a link to a youtube video from the Cornell University ornithology department that includes eerie cries of loons.

http://www.youtube.com/watch?v=4ENNzjy8QjU

Common loon.

Loons dive under water and catch small fish–their primary prey, though they also feed upon aquatic invertebrates, insects, and some water plants.  They can take large fish as well, but need to drag them to shore and mangle them before dining.  Loons like to nest on uninhabited islands in lakes, explaining why they migrate north during spring to places like Minnesota where there are lots of lakes.  I always thought of loons as a strictly northern bird, but a few years ago a checklist and count of waterfowl on Clark Hill Lake included a few dozen common loons.  I didn’t know they spent winters in wetlands across the south and have never seen one.  They’ve been reported from many counties in Georgia but are most numerous near the coast where small fish are always plentiful.

Counties in Georgia where common loons have been sighted.  The map should include Lincoln County where they’ve been seen on Clark Hill Lake. The common loon winters in Georgia but doesn’t nest here.  Its present day nesting grounds were under glacial ice during much of the last Ice Age.  Did it nest in Georgia then?

During the Ice Age the present day nesting range of the common loon was under glacial ice.  They must have nested farther south then.  The region between the southern lobe of the Laurentide glacier and the Ohio River may have had numerous small lakes created by meltwater pulses which flooded low lying areas.  Perhaps this is where they mostly nested then.  It’s possible they nested and lived year round in the southeast during the Ice Age.  The overall population probably increased as the glacier receded and opened up more favorable habitat in the north, and they eventually abandoned their southern breeding grounds, though they still return to take advantage of ice free feeding opportunities during winter.

A loon fossil (looks like an intact wing) found in Florida by a member of the Fossil Forum.  This is a nice specimen. Did they breed and nest in Florida then or was it just spending the winter?

Three other species of loons spend winters in Georgia.  The red-throated loon (Gavia stellata) has been reported from 19 counties; the Pacific loon (Gavia pacifica) has been reported from 4 counties; and the yellow-billed loon (Gavia adamsii) is a rare accidental reported from only 1 county.

 

 

 

The Nature of Paleolithic Art by R. Dale Guthrie

I recently finished reading The Nature of Paleolithic Art by R. Dale Guthrie.  Dr. Guthrie also authored Frozen Fauna of the Mammoth Steppe and dozens, perhaps hundreds, of articles for scientific journals, many of which I’ve read.  It took me almost a month to read The Nature of Paleolithic Art because it’s 500 pages and has small print and numerous pictures on every page that are worth careful examination.  The book is a brilliant creation, taking decades of research and writing to complete.  It’s well-written and the line drawings replicating the cave paintings show Dr. Guthrie is a talented and patient artist.  Because I can’t live in the Pleistocene as I so often fantasize on this blog, I wanted to get inside the heads of the humans who actually did.  Dr. Guthrie does this with his detailed analysis of their art.  Most books about paleolithic art have been written by art historians, anthropologists, and archaeologists, but this book is the first written from the point of view of a vertebrate paleontologist, making it unique.  I noticed amazon.com didn’t have much information about this book, so I will remedy this with a chapter-by-chapter review.

The first chapter is entitled “Drawn from Life.”  It consists of a discussion of how this work compares to others on the subject.  This is where Dr. Guthrie introduces one of the important themes of his book: Most paleolithic art was drawn realistically and the images were not representations symbolizing magic or religion, a view held by many anthropologists.  I agree with Dr. Guthrie.  To me this seems rather obvious–too many scholars look for something deep and complex when there is a much simpler explanation.  The people living in Europe then depended on hunting and that is what they depicted.  This chapter also covers the ecology of Pleistocene Europe.  Humans lived on the ecotone between southern European forests and the vast mammoth steppe that stretched from the British Isles to Alaska.  And there are detailed descriptions of cave geology, preservation, and taphonomy.

The second chapter is “Paleolithic Artists as Naturalists” which was perhaps one of the most interesting for me (well…that and the sex chapter).  He finds usable information about extinct species and extirpated subspecies from cave paintings.

Page from The Nature of Paleolithic Art.  The top drawings depict the most common large mammals living in Eurasia during the Pleistocene including Woolly mammoths, woolly rhinos, Megaloceros–a giant extinct deer, elk, caribou, aurochs–wild cattle, bison, musk-oxen,  horses, asses, ibex, sable antelope, cave bear, brown bear, lions, hyenas, wolves, and humans.

For example the cave paintings inform us that European lions had no manes, and horses in southwestern Europe had some striping, an adaptation for living in brushy habitat.  Dr. Guthrie shows the reader how the cave paintings represent real animal behavior–there are depictions of mating and flight response.

Chapter 3 is “Tracking down the Pleistocene Artists.”  Dr. Guthrie conducted a study that analyzed the hand prints on the cave walls.  Statistical differences between age and sex exist in the measurements of finger and palm size.  The cave painters made the hand prints by spitting a mouthful of red ocher over their hands.  Based on hand measurements, Dr. Guthrie determined most but not all the cave painters were boys aged 12 and under.

A statistical analysis of hand measurements suggests most the cave painters were boys aged 12 and under.  The kids making the hand prints were likely the same kids who were drawing the animals.

Although many cave paintings are masterpieces, most look like something a third grader might doodle.  The highest quality paintings are famous, but they’re vastly outnumbered by little known drawings that were done by less talented or less experienced artists. 

It’s no coincidence that nearly every cave with paleolithic art was discovered by teenaged boys.  During the paleolithic just like in the present time, adventurous boys would be the most likely members of society to venture into caves.  Because life expectency was so low then, children made up a bigger percentage of the population then than they do now and teenaged boys would have been a significant segment of society.  Contrary to popular belief, paleolithic people didn’t live in caves but inhabited open air sites, temporary huts, and rock shelters.  This explains why most of the cave artists were young boys.

Chapter 4 is “Testosterone Events and Paleolithic Imagery.”  This one is about the evolution of human behavior and art.  He explains the evolutionary reason why paleolithic men and women differed in the partition of labor and why modern politically correct attitudes stifled early studies on the role evolution played in making men the hunters while women were better able to perform tedious tasks such as sewing clothes.  Younger men with higher levels of testosterone than women took more risks when hunting and were also more likely to explore caves.  Accordingly, the art on caves is more representative of a young male’s point of view.  Much information about women’s contributions is missing–the clothes they made are organic and long gone.  Boys painting on cave walls rarely drew people wearing clothes, even though they must have, considering the harsh climate.  There are rare exceptions.  The few pictures depicting clothes show paleolithic people wearing parkas, hoods, and boots.

Chapter 5 is “The art of Hunting Large Mammals.”  Dr. Guthrie begins by reviewing the evolution of hunting behavior in hominids.  He uses evidence from physiology, sociobiology, ecology, and accounts from the ethnographic record to show that hunting was a driving force in human evolution.  He believes hunting created the modern social bond between man, wife, and child.

Incidentally, Dr. Guthrie believes the red spots on some cave paintings of Pleistocene horses represent the tracking of blood from wounded animals.  This is an alternative explanation for the ones I gave in a previous blog entry– http://markgelbart.wordpress.com/2011/12/02/pleistocene-spotted-horses/

Another page from the book.  These are line drawings of cave paintings.

The chapter on hunting is a long one covering paleolithic weapons, the use of disguises, tracking wounded game, and harpooning fish.

Chapter 6 is “Full-figured Women in Ivory and Life.”  He explains the common depiction of full-figured fat women represents the female sex when they were most fertile. In most hunter-gatherer societies, women are rarely fertile due to a combination of environmental stress and the care of an already existing baby or toddler.  Women were most likely fertile during times of plenty when they had no young children nursing.  Men evolved to identify when women were most fertile.  And, of course, young boys drew pictures on cave walls and sculpted the famous figurines because women with big boobs and big butts were what was constantly on their minds, along with hunting large mammals.

Dr. Guthrie doesn’t go so far as to suggest the possiblity that the Venus of Willendorf represents sex slavery as I did in a previous blog entry– http://markgelbart.wordpress.com/2011/10/14/the-venus-of-willendorf-pleistocene-sex-object/

But he does dismiss the notions they represent fertility or goddess cults.

I don’t agree with Dr. Guthrie when he writes that paleolithic people chose their mates carefully.  The population was so low then that people probably had a hard time even meeting members of the opposite sex who were not related to them, and they had to accept what they could get.

Paleolithic people had many sexual items and enjoyed practices we consider modern.  Cave paintings prove paleolithic women wore lingerie.  Many cave paintings depict buxom women wearing nothing but bracelets, belts, and boots.  Paleolithic dildoes (made of stone) are very common.  One broken sculpture suggests they played bondage games.

Chapter 7 is “The Evolution of Art Behavior in the Paleolithic.”  Here, he discusses the evolution of play and how art is an extension of play.  Art contributed to the survival of paleolithic people because it helped make their brains more creative which did have practical uses.  Creativeness is heritable.

Chapter 8 is “Bands to Tribes.”  Very little paleolithic art is abstract, but the development of agriculture led to an increase in the use of abstract symbols in art.  Humans needed to invent abstract symbols to account for stored foodstuffs.  Agricultural civilization changed the human experience but not all for the better–humans suffered more malnutrition from starch-based diets, they contracted diseases spread from domesticated animals, and they experienced more warfare from being in economically unequal societies.  Not a single paleolithic drawing known depicts a shield or warfare, though individual man on man violence was rarely drawn.

Chapter 9 is “Throwing the Bones.”  This was the only chapter I found uninteresting.  It’s about the evolution of the belief in the supernatural.  There’s not enough concrete evidence left about early human’s supernatural beliefs, making this part of the book too vague and unnecessarily long-winded.  That’s really the only negative criticism I have of the book.  Sometimes, Dr. Guthrie overwrites and gives 5 or 6 examples when 1 0r 2 would have been enough.  Otherwide, I enjoyed the book very much.

The Interglacial Invasion of Warm Climate Species into Southeastern North America

Humans have been enjoying a relatively stable warm climate phase for roughly 11,000 years now–a period of time known as the Holocene.  We’ve probably been experiencing an interglacial because it’s likely we’re between Ice Ages, although with the extraordinary release of CO2 from industrial activities, there’s no telling when the next Ice Age will occur.  This phase of warm stable climate has allowed agriculture to flourish.  If climate had remained unstable and as cool as it did during the last Ice Age, civilization as we know it may never have come into existence.

The most recent interglacial previous to the present one was the Sangamonian Interglacial which lasted from 132,000 BP-118,000 BP.  Climate during the Sangamonian was even warmer than that of today.  At one point during this interglacial the north polar ice cap completely melted and sea levels were higher than they are now.  Cypress swamps grew as far north as Illinois, alligators swam in rivers flowing through what today is Missouri, and giant tortoises roamed the ridge and valley region of the southern Appalachians.  This wasn’t the warmest era in geological history–it wasn’t even close to as warm as much of the Pliocene, Miocene, Oligocene, etc. ages–but it was unusually warm compared to most of the Pleistocene.  This prolonged warm climate phase allowed many frost sensitive species of vertebrates to colonize much of southeastern North America, at least temporarily.  But because cold phases of climate during the Pleistocene lasted 10 times longer than warm phases, fossils of these tropical and subtropical species are in some cases extremely rare.  There are probably more species than the following pictorial cavalcade illustrates, but these are the ones confirmed by science.

Eremotherium laurillardi, the largest ground sloth to ever live in North America, grew to 18 feet long and weighed up to 3 tons.  Fossils of this species are quite common along Georgia’s coastal fossil sites which mostly date to the Sangamonian and early Wisconsinian.  Cold climate eventually drove them from what is now Georgia, but they persisted in Florida until maybe 30,000 BP when the beginning of the LGM became too cold for them even there.  They did continue to live in South America until 10,000 BP when hunting Indians likely drove them to extinction.  If it wasn’t for man, they may have recolonized the gulf coast of today.  2 species of ground sloths (Jefferson’s and Harlan’s) were able to survive in North America during the Ice Age, but Eremotherium must have been incapable of tolerating frosts.

Evidence that the South American marsh deer (Blastoceras dichotomous) once lived in the southeast comes from 1 mandible found at Saber-tooth Cave in Florida.  It was given the scientific name, Blastoceras extraneous, but was likely the same species populating the present day South American pampas.  Dr. Richard Hulbert expressed doubt in his book, The Fossil Vertebrates of Florida, that this mandible was correctly identified, but that was before he himself indentified the presence of collared peccaries in the Florida Pleistocene–a big surprise.

Collared peccaries were only identified from the Florida Pleistocene within the last few years.  Apparently, they colonized the south during the Sangamonian and probably other interglacials.  2 other species of peccaries–the flat-headed and the long-nosed–did commonly occur in the south during cold stages as well.

1 ocelot specimen from the Florida Pleistocene proves this cat lived in the south.  It seems that this cat should be able to survive in Florida today.  I suspect Indians coveting its spotted coat led to its demise there.

Fossil evidence of a small species of cat resembling the modern day margay comes from Florida and 2 widely separated sites in Georgia–Ladds and the Isle of Hope site.  Scientists are uncertain of the identification–it’s either a margay,  jaguarundi, or a distinct extinct species.  Despite the scientific genus name, Leopardus, it’s not at all closely related to a leopard.  Was it climate or paleo-Indian desire for spotted coats that restricted this species to isolated jungles?

Giant tortoise fossils dating to the Pleistocene were found at Ladds, the northernmost locality, though during the Pliocene, which was mostly warmer than the Pleistocene, they lived as far north as Kansas.  In contradiction to what most scientists think, I suspect giant tortoises were capable of surviving light frosts.  See my reasoning in a blog entry from my April 2011 archives.

In the Sangamonian of Georgia I suspect alligators may have ranged into the Etowah River.  If giant tortoises lived in the area, alligators surely must have been able to live there too.

Many species of South American and Central American birds also extended their range north in Sangamonian times.

Pleistocene Fossil Felid Ratios from the University of Florida Database

I followed the same procedure from last week’s study but counted the number of cat fossils in the University of Florida’s Natural History Museum database instead of dog fossils.  I only counted fossils dating from the Rancholabrean Land Mammal Age 300,000 BP-11,000 BP.  The results may be off a little because I was scrolling down while looking at a computer screen.  The results may also be misleading because many specimens may come from just 1 individual.   Nevertheless, I think the data reveals a good estimate of the ratio of species composition during the Pleistocene.

Listed on the University of Florida Museum of Natural History database, I counted 46 jaguar (Panthera onca) specimens, 21 giant panther (Panthera atrox) specimens, 42 saber-tooth (Smilodon fatalis) specimens, 6 scimitar-tooth (Dinobastis serum) specimens, 41 cougar (Puma concolor) specimens, 46 bobcat (Lynx rufus) specimens, 12 river cat (Leopardus amnicola or weidii) specimens and 1 ocelot (Leopardus pardalis) specimen.

The results are similar to those reported by the amateur fossil collectors who post on the fossil forum.  The most significant difference between their reports and database information is abundance of jaguar to saber-tooth abundance.  Amateur fossil collectors claim jaguar fossils are much more common in Florida than saber-tooth, though they do collect the latter and some have found scimitar-tooth specimens as well which are rare in the database.  It may be that the UF database includes a skeleton of a saber-tooth accounting for multiple specimens from 1 individual.

Dire wolves accounted for 64 specimens in my previous study, making them 33% more common, at least in the fossil record than any single species of big cat.  Overall, big cats combined outnumbered dire wolves 156 to 64, making large felines more than twice as common as dire wolves.  Perhaps there was less competition among species of canids, but more among felids.

Pleistocene habitats favorable to various species of big and small cats varied widely.  Mesic oak forests and cypress swamps, which expanded during warm interglacials and interstadials, favored jaguars, river cats, and ocelots.  Jaguars are adabtable enough to live in desertlike brush conditions which were common during cold arid stadials.  Cougars and bobcats thrive in many different types of environments.  The exact environments favored by giant panthers, saber-tooths, and scimitar-tooths is unknown, but it’s likely they were capable of adapting to many different ecotones.

Saber-tooths were evidently one of the most common large carnivores south of the ice sheets in North America.  They were actually no larger than a modern day jaguar.  Saber-tooths never colonized Eurasia, but a distant cousin, the scimitar-tooth had close relatives that did live from the southern tip of Africa to Alaska.  Scimitar-tooths also had longer front legs but these were more slender than those of the saber-tooth.  Their fangs were also smaller and more curved.  In Africa, Asia, and Europe scimitar-tooths became extinct much earlier than saber-tooths did in America.  I suspect they never learned to fear man, explaining their earlier extinction.  I suggest fanged cats didn’t often back down from anything.  Scimitar-tooths probably colonized southeastern North America during stadials when grasslands expanded due to dry climate which in turn caused an increase in the populations of ungulates. 

Giant panthers probably resembled large maneless lions.  True lions did live in Alaska and across Eurasia.  But south of the ice sheets in North America, the common ancestor split into 2 different species–Panthera atrox and Panthera onca.

This image comparing Pleistocene jaguars with modern jaguars may be a slight exaggeration, but jaguars did grow bigger during the Pleistocene because they preyed on larger mammals and had more competition among carnivores.

I’ll write more about the presence of margays and ocelots in Pleistocene Florida in my next blog entry.

Here are some related articles about big cats from my archives.

“Panthera atrox! What Kind of Cat was it?”– http://markgelbart.wordpress.com/2010/07/28/panthera-atrox-what-kind-of-cat-was-it/

“Why did fanged cathttp://markgelbart.wordpress.com/tag/saber-tooth/s have sloping backs and large forelimbs?”–

“Two new studies of saber-tooths.”– http://markgelbart.wordpress.com/2011/07/08/two-new-studies-of-sabertooth-smilodon-fatalis-anatomy/

“Cougars vs. jaguars”–http://markgelbart.wordpress.com/2010/07/08/cougars-vs-jaguars/

Pleistocene Fossil Canid Ratios Recorded in the University of Florida Database

The abundance of Pleistocene fossil sites in Florida has allowed the university in Gainesville to become a center of information for other scientists.  Scientists excavating new fossil sites use existing fossils at the University of Florida Museum of Natural History to help identify the new specimens they pull from the earth.  It’s not always easy to differentiate closely related species–the subject of this blog entry, the canids, are notoriously difficult to distinguish.  Vertebrate zoologists and paleontologists measure and describe every part of every bone and tooth when examining new specimens.  They publish this information in scientific journals and accumulate knowledge of the size limits and shape variations of a particular species’ anatomy.  If a newly discovered fossil tooth for example doesn’t fit any known pattern of shape or size, than scientists suspect they may have discovered a new species.  The more data scientists have, the better able they are to identify new species and spot evolutionary trends over time within a species.

Fossil collecting is popular in Florida, thanks to all the sinkhole lakes and caves with basal chemistry in the soil that preserves bones.  Amateur fossil collectors have many more fossils in their collections than the University of Florida’s Natural History Museum..  Many are for sale as well.  It would be a great benefit to science, if collectors made arrangements to donate their collections to the museum upon their deaths.  Many valuable specimens have been lost when their owners die and family members, not interested in the subject, lose track of where they put the old bones.

My little study is limited to canid fossils listed on the University of Florida database and leaves out the great many more in the hands of amateur fossil collectors.  I also limited this survey to the Rancholabrean Land Mammal Age (300,000 BP-11,000 BP), leaving out Armbruster’s wolf which dominated the middle Pleistocene before being replaced by dire wolves.  Nevertheless, I think there’s enough information to suggest relative canid species abundance during the late Pleistocene.  Keep in mind, I was counting on a computer screen while scrolling down, so my numbers may be off slightly.

Listed on the Florida Museum of Natural History’s database, I counted 64 dire wolf (Canis dirus) specimens, 34 coyote (Canis latrans) specimens, 1 red wolf (Canis niger) specimen, 9 domestic dog (Canis familiaris) specimens, 0 dhole (Cuon alpinus) specimens, and 55 gray fox (Urocyon cineorgenteus) specimens.

The fossil record strongly suggests that from 300,000 BP to about 11,000 BP dire wolves were by far the most common large canid being about twice as abundant as coyotes.  Red wolves were rare but present.  Gray foxes were just as common during the Pleistocene as they are today.  These neat little foxes have the ability to climb trees, a skill that saves them from their larger relatives.  There is no evidence of dholes but as I wrote in a previous blog entry http://markgelbart.wordpress.com/2011/06/01/did-the-dhole-cuon-alpinus-range-into-southeastern-north-america-during-the-pleistocene/ , I suspect they may have periodically colonized parts of the southeast but in numbers too low to leave fossil evidence.

Dire wolves were the dominant large canid in the southeast (and all across North America south of the Ice Sheets) during the late Pleistocene.

Coyotes probably occupied a niche similar to African jackals.

Gray foxes thrived in areas where they had access to trees and could escape larger predators.

The presence of domesticated dogs in the Pleistocene fossil record puzzled and surprised me.  I almost didn’t even do a database search for Canis familiaris and only did so as an afterthought.  Most anthropologists don’t think humans domesticated dogs until after the Pleistocene about 10,000 years ago, but the fossil evidence contradicts this.  In fact scientists recently discovered the skull of a domesticated dog in a Siberian cave that dates to 33,000 BP.  They determined  this particular domesticated dog was not the ancestor of the lineage that led to today’s dogs but instead its descendents died out.  It’s probable that there were many early lineages of domesticated dogs that ceased to exist for various reasons.  Perhaps that group of people died out or stopped keeping dogs.  The popular idea that people domesticated dogs by kidnapping and raising wolf pups is a misconception.  Scientists think it’s the other way around–dogs adopted us.  Dogs are descended from the wolves which had the least flight response.  Wolves that hung closely around human campsites for access to leftovers gave birth to pups with floppy ears, multi-colored coats, and other dog traits that differentiate them from other wolves.  The gene for tameness shares a pathway with the gene for these physical characteristics.  So it’s likely that dogs adopted people in many different geographic locations wherever wolves (Canis lupus) began occupying areas adjacent to human campsites.  Obviously, dogs either followed or were brought to Florida by the Paleo-Indians.

The authors of a chapter in the book The First Floridians and the Last Mastodons suggest that all the coyote fossils found in Florida are actually domesticated dog fossils, but they only knew of a handful of coyote fossils.  Apparently, they didn’t know 34 specimens had been found.  I doubt scientists made that many misidentifications.

Dire wolves succeeded in becoming one of the dominant predators in the environments of southeastern North America where they found a wealth of prey roaming the open woodlands and savannahs.  Everything from bison and horses to deer and rabbits sustained them, and a mammoth or mastodon that died of natural causes provided a feast.  Coyotes successfully co-existed with dire wolves by scavenging large predator kills and by hunting rodents.  Red wolves must have been restricted to islands and perhaps deeply wooded swamps where they could survive on deer and small game.  Their niche must have been areas with lower densities of prey as opposed to grasslands that hosted large herds of ungulates.  Following the extinction of the megafauna and dire wolves, forests replaced grasslands and red wolves increased in number and drove coyotes completely out of the south.  But after European settlers wiped out the red wolves, coyotes returned.

References:

Ovodov, Nikolai, et. al.

“A 33,000 Year Old Incipient Dog from the Altai Mountains of Siberia: Evidence of the Earliest Domestication Disrupted by the Last Glacial Maximum”

Plos One 6 (7) 2011

http://www.flmnh.ufl.edu/databases/vp/intro.htm

The Dunwoody Nature Center

I attended my nephew’s bar mitzvah in Dunwoody, Georgia last weekend.  Dunwoody consists of dozens of subdivisions and plenty of shopping centers and absolutely no rural farmland.  I didn’t hold out much hope for a nice nature walk here–the traffic is terrible.  But at least the developers left a lot of trees standing.  I decided to walk from my sister’s house to a little park known as the Dunwoody Nature Center and I discovered a surprising gem.

This white oak was about 4 feet in diameter.  White oak is a common tree in Dunwoody.

From the composition of the trees left standing most of Dunwoody must have once hosted a pretty nice dry upland forest.  Too bad developers converted it into a crowded suburb.  Today, white oaks, black oaks, southern red oaks, shortleaf pines, and loblolly pines are the dominant trees.  The Dunwoody Nature Center slopes sharply down toward Wildcat Creek, the name of which is a relic to its former status as a wilderness.  The woods here are dominated by beech, white oak, sweetgum, river birch, and loblolly pine.  I was stunned to see a woodlot of mostly beech trees in central Georgia.

A mature beech tree growing on the edge of a rocky creek.  It’s surrounded by many immature beech saplings.

Fossil pollen studies show beech was a common tree in the south during the end of the Ice Age when the Laurentide glacier began melting and releasing more moisture in the atmosphere creating a climate that was still cool but more rainy than it was during the height of the Ice Age.  The presence of abundant beech in the fossil record is indirect evidence of massive flocks of passenger pigeons.  Passenger pigeons fed on acorns–in some places completely eliminating the oak seed crop…and the beech’s competition.  Although beech trees produce an edible nut, they can also spread from roots and could survive their seed being consumed by passenger pigeon flocks.  Since the passenger pigeon’s demise, oak forests have been replacing beech forests in many areas.  So I was delighted to see this remnant beech forest in central Georgia.

Wildcat Creek flows through a granite outcropping.  Here is a miniature waterfall.

Two little league baseball fields take up about half the space of the park.  The park is heavily used by dog and toddler walkers.  It’s popularity shows that the planning commission in charge of developing Dunwoody should have arranged for the purchase of more land for more parks.