The Chimney Top Fire

June 24, 2017

The Chimney Top is a series of dry rocky ridges located in the Great Smoky Mountains National Park where slate, schist, and phylite overlay erosion-resistant sandstone.  In some places precipitation has eroded away the top rocks, exposing the sandstone, and the formations resemble chimney tops, hence the name.  Last November, 2 unnamed juveniles set the surrounding forest on fire.  Drought conditions fed the fire, and it was fanned by 80 mph mountain wave winds.  Hot air from the fire rose up the mountain and when it met stable air, it ricocheted and accelerated downward in waves.  The fire burned over 15 square miles and spread into neighboring Gatlinburg, Tennessee, killing 16 people, 2 black bears, and uncounted small animals.  Yet, this forest will recover because many of the plant species growing on the ridge are well adapted to fire and in some cases even dependent upon it.

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Needles and cone of the table mountain pine.  This species depends on fire to open its cones.

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Fireweed also depends on fire.

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The Chimney Tops.  Erosion resistant rock explains the chimney-like formations.

Photo of a burned ridge on Chimney Top.

The Chimney Top environment consists of rock chestnut oak (Quercus montana), table mountain pine (Pinus pungens), and heath balds.  Rock chestnut oak is fire resistant, and it thrives in the rocky shallow soils on the ridge.  Table mountain pine also grows well in the shallow soils, and it depends upon fire to open its seed cones.  Although long exposure to hot sun opens table mountain pine cones, the process is best facilitated by fire.  Park service employees noted a rain of pine seeds in the air a few days after the fire.  In 5 years the burned over ridges will be covered with pine saplings and fireweed.  Some heath balds completely burned to the ground–an unusual occurrence here because this region is the rainiest spot east of the Mississippi.  Heath balds are evergreen shrub communities consisting of mountain laurel (Kalmia latifolia), Catawba rhododendron (Rhododendron catawbiense), various species of blueberries (Vaccinium sp.) and huckleberries (Gayluccia sp.), and 1 deciduous tree–mountain ash (Sorbus aucuparia).  Heath balds are often adjacent to grassy balds and surrounded by forests of red spruce and hemlock.  Heath shrubs thrive on shallow acid soils located on mountain slopes.  Both heath and grassy balds are of ancient origin.  (See: https://markgelbart.wordpress.com/2016/05/16/the-extinct-helmeted-musk-ox-bootherium-bombifrons-and-appalachian-grassy-balds-during-the-pleistocene/ )  Scientists studied heath balds and discovered they grow on a layer of peat underlain by charcoal.  This suggests heath balds occasionally do burn completely, yet regrow in the same location.  This fire gives scientists the first chance to ever witness the rebirth of a heath bald.

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Heath bald.

Forests are resilient.  The area in the photo below was clear cut during 1910.  The original forest consisted of chestnut, oak, and hemlock; many with trunks 5 feet in diameter.  The destruction of this locality spurred the creation of the Great Smoky Mountains National Park in 1926.  The 2nd growth forest that replaced the original tract is not as impressive but at least it is green.

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This area was clear cut in 1910.  It has nicely recovered but is not as impressive as it was originally.

Cades Cove

June 19, 2017

Most of the Great Smoky Mountains National Park is heavily wooded, and wildlife usually stays hidden in thick vegetation.  Cades Cove is 1 of the few areas in the park where tourists can reliably see wildlife because it is an open beautiful valley of fields and thin fingers of forest, resembling what many southeastern landscapes looked like until the mid-19th century.  Indians set fire to the valley annually to improve habitat for game animals, and white settlers maintained the open nature of the valley by using it as pasture and by planting row crops.  The valley remained open when the National Park Service took over the site 90 years ago.  Today, a 1-way loop road encircles the valley, making for the best accessible wildlife watching in the park.  I rode my car on the Cades Cove loop road last Saturday evening with my wife and daughter.  We saw >50 horses, 20 deer, 2 black bears, 1 squirrel, 1 turkey, and lots of crows and chimney swifts.

The herd of tame horses is located near the beginning of the loop road.  Many different breeds are represented including spotted palominos, Clydesdales, and solid black and brown horses.  I saw cowbirds foraging between the horses.  Fossil evidence shows horses did inhabit this region during the Pleistocene.  I would like to see the park service allow horses to go wild here.  Wild horses belong in North America.

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There’s an herd of over 50 horses near the entrance to the Cades Cove loop road.

Black bear sightings caused several traffic jams on the loop road.  There are hundreds of signs telling tourists to pull over when they want to stop and see the wildlife, and other signs constantly warn to stay at least 50 yards away from bears and deer.  Most tourists ignore these signs.  They stop their cars in the middle of the road, rush toward the bear, and get as close as they can to photograph the bruin.  We were stuck in 1 traffic jam for 20 minutes.  At least I did get to see wild black bears for the first time in my life.  I’d rather live in a world where bears outnumber people.  It has been thousands of years since bears outnumbered the entire population of Homo sapiens on earth but before the development of agriculture they did.

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We saw 20 deer.  This buck snuck behind me.

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This was the only turkey I saw in Cades Cove.  I expected to see more.  While driving through the park the following day I saw an hen with 2 chicks cross the road.  Why did the turkey cross the road? 

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There are 4 deer in this photo.  2 are laying down but their antlers are visible.

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This was the only live squirrel I saw in Great Smoky Mountains National Park.  I was surprised I didn’t see more.

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We saw 2 black bears on the Cades Cove loop road.  Look at how close these 2 stupid asses got to the bear.  They are underestimating how dangerous this situation is.  There must be at least 100 signs telling people to stay at least 50 yards away from the bears and deer.  Instead, people rush in and try to get as close as possible to take a photo.  That bear could be mauling them in about 2 seconds.

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These are the rare and extirpated species that used to live in the Great Smoky Mountains National Park. Spotted skunks are rare, Indiana bats are endangered, northern flying squirrels are probably extirpated here, fox squirrels haven’t been seen for decades in the park, and northern water shrews are uncommon.

I was surprised I didn’t see more turkeys or squirrels.  The latter probably stay in the tree tops for much of the day.  I also expected to see woodchucks, rabbits, and maybe wild boars.  Woodchucks are more active in the morning, and I did see 4 of them while driving through the North Carolina mountains on the way home the following day.  I can’t explain the absence of rabbits because there is plenty of excellent habitat for them in Cades Cove.  Perhaps they were hidden in the tall grass.  Ironically, I saw a road-killed wild pig 5 miles from my house on the drive home the next day as if the wildlife watching Gods wanted to reward me with a kind of epilogue to my trip.  Despite how common wild pigs are supposed to be, this was the first road-killed specimen I’ve seen in the Augusta, Georgia area.

The National Park Service should introduce bison, elk, and cougars to Cades Cove.  I know the addition of cougars would be controversial, but the park service should be inspired to come as close to possible to establishing a complete ecosystem here.  More open areas should be created as well so that wildlife populations could increase.

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The National Park Service should introduce bison and elk to this side of the park to fill up this empty space.

Bird watching at Cades Cove was not as good as in Townsend, Tennessee where our hotel was located.  I saw 5 species of birds in Cades Cove compared to 11 species in town.  However, I did encounter 1 unexpected species outside of Cades Cove but inside Great Smoky Mountains National Park.  I saw a raven while driving in the higher elevations, then saw another raven on the way to Cades Cove at a lower elevation.  This was the first time I’d ever seen live ravens in the wild.  I mistakenly thought ravens were rare here because there is only 1 raven nesting site in the entire state of Georgia.  But according to the National Park Service, the raven is a fairly common year round resident in the park.  Ravens look like humongous crows.  The birds I saw were far too large to be crows.  They were about the size of a red-shouldered hawk.  Crows are more common here, however. In addition to the 5 species of birds I saw at Cades Cove, I heard the constant song of the field sparrow.  Eastern meadowlarks are also supposed to be common here, but I didn’t see any.  I have never seen an eastern meadowlark.

Night fell by the time we left the Cades Cove loop road.  I was surprised at the abundance of lightning bugs.  Special tour buses take tourists through the park at night to see the amazing light show displayed by the synchronous firefly (Photinus carolinus) during late May and early June.  We probably saw some of the other 18 species of lightning bugs found in the park because it was too late in the season for P. carolinus. Lightning bugs are not bugs, nor are they flies.  They are beetles.  Their larva prey upon snails, slugs, and insects for a year or 2 before they transform into flying adults for the final few weeks of their lives.  Different species flash at different intervals and that is how males and females of the same species recognize each other.  Lightning bugs are only seen occasionally in Augusta, Georgia.  They are abundant in the Great Smoky Mountains because the moist forests support a large population of their favorite food–escargot.

Video from you tube of the synchronous fireflies.

The Cookie Cutter Cat (Xenosmilus hodsonae)

June 13, 2017

Larry Martin is the paleontologist who invented the fanciful name of “cookie cutter cat” for this extinct species.  He proposed this big carnivore killed its prey by taking a bite and retreating, thereby removing a piece of flesh like a cookie cutter removes a section of dough.  Supposedly, the cat then waited around for its victim to die from the wound.  I don’t buy it.  It seems unlikely a predator would cease attacking a wounded animal.  Instead, I believe this powerfully built animal held its prey down with its sturdy forelimbs and bit through the throat.  I suspect this is how all species of fanged cats dispatched their prey.

The cookie cutter cat is a newly recognized species.  Though commercial fossil collectors discovered 2 nearly complete skeletons at the Haile fossil site in 1981, scientists didn’t identify it as a new species until 20 years later.  At first scientists assumed it was a scimitar-toothed cat (Dinobastis serus) based on skull and dentition.  There were 2 lines of fanged cats during the Pleistocene in North America–the scimitar-tooths or Homotheridae and the saber-tooths or Smilodontheridae.  Both belonged to the subfamily Machairodontinae.  Scimitar-tooths were previously known to be long-limbed and built for chasing down prey, while saber-tooths were robust and built for ambushing their victims.  However, paleontologists eventually realized the cookie cutter cat was an exception.  It was a scimitar-tooth cat built for ambushing its prey, like the saber-tooth line of cats.  Cookie cutter cats were robust and powerful and short-limbed.

Mounted skeleton of the extinct cookie cutter cat.  It was stout like a bear and about the size of a lion.

Fossils of cookie cutter cats have been found at 7 sites in Florida including Haile, Sarasota, Citrus County, Levy County, Santa Fe River, Hillsborough, and Marion County.  Specimens identified as belonging to the Xenosmilus genus  have also been found in Arizona and Uruguay.  Cookie cutter cats are known to have lived during the late Pliocene and early Pleistocene between 2.5 million years BP-1.5 million years BP.  The specimens at Haile were associated with many bones of peccaries, a likely prey item.

References:

Martin, Larry; and J. Babiarz, J, Hearst, and V. Naples

“Three Ways to be a Saber-tooth Cat”

The Science of Nature 87 (1) 2000

See also the University of Florida Museum web article.– https://www.floridamuseum.ufl.edu/florida-vertebrate-fossils/species/xenosmilus-hodsonae

 

 

 

 

 

 

Predator and Prey in the Early Pleistocene of Florida

June 8, 2017

Pleistocene ecosystems supported a great variety of large predators.  During the early Pleistocene the saber-toothed cat (Smilodon gracilis, ancestor of S. fatalis) and Edward’s wolf (Canis edwardii, possible ancestor of C. dirus) were 2 important carnivores that kept herbivore populations in check.  A study analyzed the chemistry of megafauna bones from 2 early Pleistocene-aged sites in Florida to determine what these 2 predators chose to prey upon.  The study included data from 110 specimens of 12 species excavated from Leisey Shell Pit, and 51 specimens of 9 species found at Inglis 1A.  Species used from Leisey Shell Pit in addition to the 2 carnivores mentioned above included mammoth, mastodon, gompothere, horse, 2 kinds of llama, 2 kinds of peccaries, white tail deer, and tapir.  Subfossil remains from this site date to between 1.5 million years BP-1.1 million years BP during an interglacial climate phase when the environment is thought to have been lowland forest and swamp, though there must have been some grassland.  Species used from Inglis 1A were mastodon, white-tail deer, peccary, tapir, horse, llama, and an extinct species of pronghorn along with Smilodon and Edward’s wolf.  Subfossil remains from Inglis 1A date to between 1.9 million years BP-1.6 million years BP during a glacial climate phase when the environment is thought to have been a mix of longleaf pine savannah, oak scrub, and forest.

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Jaw bone of the extinct Edward’s wolf, 1 of the oldest wolf species known to have lived in North America.

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Photoshopped Smilodon gracilis, the evolutionary ancestor of the late Pleistocene Smilodon fatalis.

The results of the study indicate Edward’s wolf ate a greater variety of prey than Smilodon, but both species were adaptable to changing environments.  During the interglacial period Smilodon ate herbivores that fed in forest environments (mastodon, deer, tapir, paleollama), while wolves mostly ate grassland herbivores (mammoth, horse).  However, during glacial periods when grasslands predominated Smilodon adapted by eating more grassland herbivores.  Choice of prey among individual saber-toothed cats varied.  Some individual cats ate nothing but forest herbivores, while others ate just grassland herbivores.  I think this shows saber-tooths were territorial animals that stayed in the same home range their entire life.  They ate whatever prey occurred within their established territory.  Herbivores that fed in both forest and grassland (large-headed llamas, gompotheres, peccaries) likely fell prey to both carnivores.

Reference:

Feranec, Robert; and L. Desantis

“Understanding Specifics in Generalist Diets of Carnivores by Analyzing Stable Carbon Isotope Values in Pleistocene Mammals of Florida”

Paleobiology 40 (3) 2014

Bearzilla’s Diet

June 4, 2017

WordPress has a feature that lets me see how many daily views my blog articles get.  For several years my article entitled “Bearzilla: the Biggest Bear Ever” is almost always the single highest viewed article of the day. https://markgelbart.wordpress.com/2012/12/10/bearzilla-the-biggest-bear-in-history/  The subject of that popular blog entry is Arctotherium angustidens, an extinct South American species of bear that reached estimated weights of 3500 pounds–the largest size of any bear known to science.  In that blog entry I also discuss the largest specimens of extant species of bears and include a photo I ripped off from google images of a 2100 pound polar bear.  I suspect that photo is what draws so many views.  I came across a fairly recent research paper in the Journal of Paleontology about A. angustidens with enough information for me to write an addendum to my original article.

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Illustration showing the early Pleistocene giant short-faced bear that lived in South America. It later evolved into a smaller more herbivorous species.

Scientists studied the pathology, morphology, chemical signatures, and biomechanics of A. angustidens bones to determine what this species ate.  Missing, broken, and worn teeth were common.  The evidence of these dental problems suggests the bears were damaging their teeth when they clumsily gnawed on bones.  Some bear teeth even had bone splinters lodged in them.  An individual young female bear had a tooth infection caused by a bone splinter in its tooth, and this was the probable cause of death.  These giant bears had large teeth cheek similar to the extant giant panda (Ailuropoda melanoleuca), but pandas don’t exhibit tooth damage on their diet of bamboo.  The frequent occurrence of tooth damage in Arctotherium can only be explained by a diet high in bone consumption.

An analysis of stable isotope ratios in Arctotherium bones does suggest this species included lots of meat in its diet, but it also ate plant material.  The scientists conclude Arctotherium was an omnivore.

When large bears first colonized South America they competed with just a few large carnivores such as saber-tooth cats.  There was an abundance of large slow-moving prey the bears could wrestle down.  Eventually, more species of predators colonized the continent, and some prey species evolved into faster runners.  Other prey species–the large ground sloths for example–may have evolved into stronger adversaries as well.  Bears that consumed more plant material had a better chance of surviving than those that competed with predators or failed to obtain prey.  This may be why Arctotherium’s descendants  evolved to eat more plants than meat.

Reference:

Soibelizon, Leopoldo; et. al.

“South American Giant Short-Faced Bear (Arctotherium angustidens) Diet: Evidence from Pathology, Morphology, Stable Isotopes, and Biomechanics”

Journal of Paleontology 88 (6) 2014

Striped Skunk (Mephitis mephitis) Dispersal During the Pleistocene

May 30, 2017

Most people don’t even think about where and when the various species of wildlife inhabiting their neighborhood originated. No matter how common a particular species may seem, it has not always been there.  The striped skunk is a generalist species that occurs all across the United States, and it is quite common in many regions, especially rural farm country. It is found in forests, fields, wilderness and suburbs.  They are an adaptable species, thanks to their omnivorous diet and unique defense strategy.  Yet, striped skunks have not always existed over their present day range.

The ancestors of all American skunk species came to this continent by crossing the Bering Land Bridge over 5 million years ago.  Paleontologists assign fossils of this ancestral species to the extinct  Martinogale genus.  About 2 million years ago striped skunks in the Mephitis genus diverged from spotted skunks in the Spilogale genus.  There is fossil evidence of early species of Mephitis skunks from the early and mid-Pleistocene in Nebraska, Colorado, and Florida.  However, this early species must have gone extinct over much of its range.  By 300,000 years ago, Mephitis skunks were restricted to what today is northern Mexico and southern Texas.  All present day striped skunks descend from this ancestral population, according to a study of striped skunk genetics.  Scientists studied genetic information from 314 specimens chosen from 20 states and determined striped skunks spread east and west from this population.  Early striped skunks, like their closest living relative–the hooded skunk (M. macroura), were probably well adapted to desert environments but evolved characteristics that helped them survive in woodlands and grasslands.  Over 250,000 years ago, striped skunks crossed the Mississippi River and colonized the entire southeast.  This probably occurred during a glacial stage when the river ran low and numerous sandbars facilitated the crossing.  The lower Mississippi River has served as a barrier, isolating populations of striped skunks ever since.

Geographic distribution striped skunk phylogroups based on 601 base pairs of cytochrome-b gene in mitochondrial DNA. Pie charts indicate the proportional representation of groups in each state. The hypothesized Pleistocene and Holocene dispersal patterns for striped skunk phylogroups are indicated by unique dash marks.

Dispersal of striped skunk population during the Pleistocene based on genetic evidence from 314 specimens taken from 20 states. Map from the below referenced study.

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The hooded skunk (Mephitis macroura) is the closest living relative of the striped skunk.  Its range is Mexico and the extreme southwestern U.S.  Genetic evidence suggests this is also the geographic range where striped skunks originated.

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Nice photo showing coat variation within the striped skunk population.  Striped skunks colonized southeastern North America about 300,000 years ago.  A primitive closely related species occupied this region before that.  It’s unclear when this predecessor became extinct.

~200,000 years ago striped skunks advanced up the Rocky Mountains from their southwestern refugium.  This population split into 2 clades on either side of the Great Basin 130,000 years ago.  This western population expanded east and colonized the Midwest.  Following the end of the last Ice Age, southeastern skunks colonized New England and expanded west, coming into contact with western populations in the Midwest.  This has resulted in an admixture of once genetically distinct populations.  The history of this dispersal explains why skunk physical characteristics vary so much. The upper Mississippi River is smaller than the lower part and is not an insurmountable barrier.  Admixtures occur along the upper part of the river.  Genetic studies of raccoons, deer mice, northern short-tailed shrews, 5-lined skinks, and leopard frogs show similar dispersal histories with the Mississippi River acting as a barrier isolating populations from each other.

Reference:

Barton, Heather; and Samantha Wisely

“Phylogeography of Striped Skunk (Mephitis mephitis) in North America: Pleistocene Dispersal and Contemporary Population Structure”

Journal of Mammalogy 93 (1) 2012

Sand Dunes Rolling Across the South

May 25, 2017

Ice Age environmental conditions influenced the present day landscapes of many geographical localities, including the Carolina Sandhills.  A recent study determined Ice Age winds shaped the topography of this region.  The sand originated from loose sediment and eroded sandstone within a Cretaceous-age formation located near the surface.  Arid climatic conditions caused by glacial expansion exposed part of this formation.  Frequent droughts reduced vegetative cover, so there were bare patches of soil without tree and grass roots holding the sand in place.  I think overgrazing by megafauna during droughts played a role in denuding the landscape as well.  Cold winds blew the exposed sand into massive eolian dunes that rolled across the land.

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The Sand Hill Region is encircled in red on this map.  At least parts of it originated during Ice Ages when cold winds blew exposed sand across the landscape here.

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Vegetation stabilizes sand dunes in the region today.  Local sand dunes have been inactive for at least 6,000 years.  They were most active during the coldest driest phases of Ice Ages.

The authors of the below referenced study took core samples of sand hill sediment in Chesterfield County, South Carolina.  They found an unconsolidated layer of sand measuring from ~1 foot to about 30 feet deep.  Optically stimulated luminescence dates (See: http://www.usu.edu/geo/luminlab/whatis.html ) suggest dunes were active from 75,000 years BP-37,000 years BP when glaciers were expanding and from 28,000 years BP-18,000 years BP during the Last Glacial Maximum and again from 12,000 years BP-6,000 years BP.  The beginning of the final period of dune activity corresponds with the Younger Dryas cold reversal when average global temperatures suddenly plummeted following a warm climate cycle.  Scientists found no evidence of dune activity between 37,000 years BP-28,000 years BP and 18,000 years BP-12,000 years BP.  These dates correspond with warmer wetter interstadials when plant growth stabilized sand sheets and dunes, holding them in place.  There has been no dune activity in the Carolina Sandhills for at least 6,000 years because higher precipitation levels foster thicker vegetative growth.

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The Great Kobuk sand dune in Alaska.  During the Ice Age landscapes in the sand hill region may have resembled this, though short leaf pines, grass, and scrub oak as well as spruce were the characteristic vegetation between the dunes instead of just spruce.

Sand dunes probably advanced the most on cold windy Ice Age nights.  Experiments show air temperature is a factor in sand particle transport.  Decreasing temperatures increase air density and lower water vapor thus reducing drag on the sand particles.  Larger particles can get picked up and transported by wind more easily when temperatures drop.  The region may have experienced brutally low temperatures compared to present day averages.

Sand dune origin in the Carolina Sandhill region differed a little from sand dune formation in Georgia.  The source of sand in the Carolina Sandhills is a geological formation near the surface, but many dunes in Georgia originated from dry river beds where sand was exposed because water tables dropped.  (See: https://markgelbart.wordpress.com/2012/04/09/the-ohoopee-sand-dunes/ ).

Pollen evidence indicates the dominant flora growing between the sand dunes during the Ice Age consisted of pine, spruce, scrub oak, grass, and asters (sunflowers, daisies, etc.).  It was probably an open woodland type of environment, though scrub oaks may have formed denser thickets.  I believe shortleaf pine (Pinus echinata) and possibly Virginia pine (P. virginiana) were the dominant species of pine here then.  It was too cold and windy for longleaf pine (P. palustris), commonly found here today.  I’m no longer convinced jack pine (P. banksiana) occurred this far south.  Some pollen studies list jack pine as a species present in this region during the Ice Age.  However:

1)The present day range of jack pine is too far away from the Carolina Sandhills. It seems unlikely its range would have retracted so drastically without leaving a relic population anywhere in the south.

2)  There are no definitive macrofossils of jack pine in the south.

3) Evidence jack pine was present in the south is based on identification of pine pollen, but 1 researcher makes the compelling case that jack pine pollen is indistinguishable from shortleaf pine pollen.  (See: https://www.osti.gov/scitech/biblio/564104 ).  Jack pine pollen is distinguished from other species of pine pollen based on the size of its grains but they overlap in size with shorleaf pine pollen grains.  Because shortleaf pine occurs in the region today, it seems more likely pollen evidence represents this species, not jack pine.

The species of spruce tree present in the Carolina Sandhills during Ice Ages was probably the extinct Critchfield’s spruce.  Macrofossils of this species have been found associated with temperate species of hardwoods.  The average annual temperatures of the Carolina Sandhills during Ice Ages was probably similar to present day southern Ohio or Kentucky, not like southern Canada as some researchers estimate based on their mistaken assumptions of tree species composition.  The Carolina Sandhills are located in what was a sharp transition zone of climate during the Ice Age.  A thermal refuge existed to the southeast where warm waters off the Atlantic coast pooled because thermohaline circulation (the tropically heated water that presently flows off the coast of New England) shut down.  But temperatures sharply dropped to the north and west of this thermal refuge, not unlike conditions experienced by mountain climbers rapidly ascending a mountain.

The Carolina Sandhills likely supported significant populations of megafauna, despite the vast expanses of bare sand.  Open grassy land fed mammoths, caribou, horses, bison, llamas, and Harlan’s ground sloth.  Scrub oak thickets attracted herds of flat-headed peccaries.  Giant lions and dire wolves roamed the interdunes, seeking out megaherbivores.

Reference:

Swezey, Christopher; et. al.

“The Carolina Sandhills: Quaternary Eolian Sand Sheets and Dunes along the Updip Margin of the Atlantic Coastal Plain Province, Southeastern United States”

Quaternary Research 86 (2016)

Horse Toe Bones and 14,000 Year Old Human Shit

May 22, 2017

The oldest known evidence of human presence in North America is some pieces of shit excavated from Paisley Cave, Oregon.  Carbon-dating of this feces indicates humans crapped in the cave about 14,350 calendar years ago.  The contents of these turds consists of bison, dog, bird, fish, grass, and sunflower seeds.  One study found the amount of cholesterol and phosphate in the crap points to an animal with a vegetarian rather than an omnivorous diet, and the authors of this paper don’t believe it is human manure.  They suggest the human DNA extracted from the specimens are a result of contamination from people mishandling it.  However, the contents were mostly animal matter, so I don’t understand how the naysayers who authored this paper can come to this conclusion.  Other scientists note the presence of wolf or fox DNA in the crap.  The scientists who are convinced the turds are human believe a wolf or fox pissed on the human shit after people left the latrine.  The turds contain human hair–perhaps the best evidence people were the shitters here.  Dried crap stuck to their ass crack hairs and the hair came off when they wiped with leaves.

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Horse toe bones were found in Paisley Cave along with 14,000 year old human feces.

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A 14,000 year old human turd found in Paisley Cave, Oregon.

Many vertebrate bones and human artifacts have been discovered in the cave.  (See: https://markgelbart.wordpress.com/2010/10/29/the-paisley-cave-pre-clovis-site/ ).  Paleontologists studied the horse toe bones excavated near the human feces because they wanted to determine which species of horse co-existed with humans in this region then.  They believe with a >99% probability the toe bones belonged to an extinct species known as the Mexican horse (Equus conversidens). Most fossil material of this species has been found in Mexico, hence the name, but it likely occurred all across North America.  The Mexican horse was stocky and stilt-legged.

Paleontologists disagree over the number of horse species that lived in North America during the late Pleistocene.  Some believe there were 2 species, while others think there were more than 14 species.  Genetic evidence supports the proposed smaller number of species.

I have no doubt humans were responsible for the extinction of North American horses through overhunting and disruption of ecosystems.  When Europeans re-introduced horses to North America during the 16th century, horses went wild and thrived everywhere on the continent.  It seems unlikely an environmental change capable of causing horse extinctions occurred for such a short interval some time between 10,000 BP and 1500 AD.  Horses eat grass and coarse vegetation–plant material that never became scarce during any climate phase or change.  Climate change models of extinction don’t work at all for such an adaptable and widespread animal as the horse.

I remember when I first started studying the debate over megafauna extinction.  Opposition to human overkill as a cause of extinction centered around the flimsy argument that there was a lack of archaeological evidence of humans hunting horses in North America.  Since then, irrefutable proof humans hunted horses here has been unearthed at several sites.  Wally’s Beach in Alberta, Canada was the first site where archaeologists agreed evidence humans hunted horses was unmistakable. Bluefish Cave in the Yukon is located north of the former Cordilleran Ice Sheet.  Evidence humans hunted and ate Ice Age horses has also been discovered in this cave, and it dates to as early as 24,000 years ago.  Humans carried horse, caribou, elk, dall sheep, bison, and bird into the cave.  36,000 mammal bones have been excavated from this site.  Wolves, lions, and foxes, in addition to people are responsible for the bone accumulation.  And now, South American archaeologists believe a cave in Argentina holds evidence of human exploitation of horse.  Stone tools are found in association with human-modified bones of horse, hippidion (an exclusively South American species of horse), llama, toxodon, giant armadillo (Eutatus) and ground sloth (Megatherium and Glossotherium).

The evidence humans did hunt megafauna is mounting but will probably never convince old school archaeologists who (I believe) stubbornly refuse to admit they were wrong for so many years.

References:

Bourgeon, L.; A. Burta, T. Higgins

“Earliest Human Presence in North America Dated to the Last Glacial Maximum: New Radio-carbon dates from Bluefish Cave, Yukon”

Plos One January 2017

McHorse, Brianna; Edward Davis, Eric Scott, Dennis Jenkins

“What Species of Horse was Coeval with North America’s Earliest Humans in the Paisley Caves?”

Journal of Vertebrate Paleontology September 2016

Politis, Gustavo; M. Gutierrez, D. Rafus

“The Arrival of Homo Sapiens into the Southern Cone at 14,000 Years Ago”

Plos One September 2016

Sistiaga, A.; F. Berna, R. Laursen, P. Goldberg

“Steroidal Biomarker Analysis of a 14,000 Year Old Putative Human Coprolite from Paisley Cave”

Journal of Archaeological Science 2014

 

First Bone-eating Dog (Borophagus sp.) Tooth Found in South Carolina

May 17, 2017

The Borophagine dogs were an incredibly successful lineage of carnivores that lived from ~34 million years BP to ~2 million years BP and perhaps beyond.  They ranged throughout North America from coast to coast and from Canada to Honduras.  16 species of Borophagine dogs are known from 12 different fossil sites in Florida alone, and in the rest of the southeast specimens have also been found in North Carolina and Maryland.  Recently, an amateur fossil collector found 1 pre-molar of a Borophagus in a spoil pile at the Martin-Marietta Orangeburg Quarry located in Orangeburg County, South Carolina.  This animal was probably common in South Carolina for millions of years, but this is the only known evidence it ever existed in the state.  Paleontologists examined the tooth and determined it compared favorably to a pre-molar of Borophagus hilli, a species that reached a weight of 130 pounds.  The age of this fossil is estimated to be between 3.9 million years BP-3.1 million years BP based on associated microfossils.  B. hilli co-occurred with another species of Borophagine dog–B. diversidensThey must have occupied different ecological niches, maybe like modern day wolves and coyotes.

Jaw bone of Borophagus hilli–the Pliocene bone-eating dog.

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Artist’s depiction of the extinct bone-eating dog.  They had bulging foreheads.  Their teeth and jaws were similar to those of the extant spotted hyena–an example of convergent evolution.

Early species of Borophagine dogs were omnivorous.  Epicyon haydenii was the largest known species of canid in history, reaching weights of over 500 pounds.  This species lived between 12 million years BP-6 million years BP, and it probably occupied a bear-like ecological niche.  Borophagine dogs later evolved into more carnivorous forms, resembling modern day spotted hyenas (Crocuta crocuta) in build and dentition, hence the reason they’re often called bone-eating dogs.

Image result for Epicyon haydeni

Epicyon haydenii was the largest known canid in history, growing as large as a grizzly bear.  They were more omnivorous than their later descendants.  They lived during the Miocene.

Borophagus sp.

Scan of the lower 4th pre-molar of a Borophagus.  This is the only fossil evidence found in South Carolina of a species that was formerly common in the region for millions of years.

Despite their long reign as an important carnivore in the American ecosystem, Borophagine dogs became extinct during the late Pliocene or early Pleistocene.  The last species of Borophagine dogs co-existed with dogs belonging to the Canidae family for millions of years.  The Canidae were newcomers from Eurasia that crossed the Bering land bridge to reach North America.  Species from the Canidae family were better able to adapt to changes in the environment during the early Pleistocene and likely outcompeted Borophagine dogs, contributing to their extinction and completely replacing them ecologically.

Reference:

Tseng, Z. Jack; and Jonathan Geisler

“The First Fossil Record of Borophagine Dogs (Mammalia: Carnivora) from South Carolina USA”

Journal of Vertebrate Paleontology 36 (2) March 2016

Pygmy Sperm Whales of the Pliocene

May 14, 2017

The transition between the Pliocene and the Pleistocene about 2 million years ago was  marked by a major marine extinction event.  By contrast there was far less faunal turnover on land.  Many species of whales that no longer exist swam in Pliocene oceans.  Paleontologists recently analyzed fossil whale ear bones excavated from sites in Florida and North Carolina and determined at least 2 morphotypes of pygmy sperm whales occurred in the Atlantic Ocean during the Pliocene.  These specimens may represent different species or size variations within a single species.  Scientists can’t make a certain determination based on just the ear bones.  Extant bottle-nosed dolphins ( Tursiops truncatus ) occur as 2 different morphotypes in the Atlantic Ocean. Deep sea dolphins are larger and more powerful than near coastal dolphins, and dolphins living in estuaries and tidal rivers don’t even interbreed with dolphins living off the coast.  Yet, these 3 separate populations are considered the same species.  The extinct species of pygmy sperm whales may have also occupied different habitats.

The pygmy sperm whale fossils came from phosphate mines in Florida and spoil piles originating from Lee Creek Mine in North Carolina.  The Florida site is thought to yield fossils that are 5-4.7 million years old, and fossils from Lee Creek Mine are estimated to be between 4.8-3.1 million years old.  Ear bones of the larger morphotype were found at both sites, but the smaller morphotype was found exclusively in Florida.

Image result for pygmy sperm whales

Pygmy sperm whales are barely bigger than bottle-nosed dolphins.

Dwarf Sperm Whale Ear

Dwarf sperm whale ear bone.  The dwarf sperm whale is not the same species as the pygmy sperm whale.

The extant pygmy sperm whale ( Kogia breviceps ) grows to 11 feet long and feeds upon squid, octopus, and shrimp.  They release a kind of ink from their intestines when they are attacked by large sharks or killer whales.  I think this defense strategy is unknown among any other species of mammal.  Pygmy sperm whales are related to dwarf sperm whales ( K. sima ), and the more famous hero of the novel, Moby Dick ( Physeter macrocephalus ).  Like their larger cousin, pygmy sperm whales locate their prey using echolocation.

The sperm whale family had more relatives during the Pliocene, but those extinct species are so little known and so little evidence of them remains that we will probably never know what made each unique.

Reference:

Velez-Jaurbey, Jorge; A Ward, and C. Pimento

“Pygmy Sperm Whale (Odostecenti, Kogiidae) from the Pliocene of Florida and North Carolina”

Journal of Vertebrate Paleontology 2016