Archive for the ‘Pleistocene Mammals’ Category

Sicily During the Late Pleistocene

May 19, 2019

Over the past few weeks I read The Sicilian by Mario Puzo, author of the famous Godfather series.  He also wrote the screenplays for The Godfather and Christopher Reeve Superman movies.  His early novels were critically acclaimed but didn’t sell, so a publisher suggested he write a novel that focused on the mafia.  In his earlier novels the mafia played just a small role.  He followed this advice only to see The Godfather rejected 20 times before he finally found a publisher.  The Sicilian is every bit as good, and I’m surprised it hasn’t been adapted for the cinema.  Mario Puzo doesn’t describe the nature of Sicily much in his novel.  He does describe the island as quite arid, and he frequently mentions the “red hawks” soaring in the sky.  As a supplement to enjoying this novel I engaged in a brief study of Sicily’s natural history.

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The “red hawks” referred to in his book were probably red kites (Milvus milvus), a threatened species.

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Location of Sicily.  

Sea level fluctuations during the Pleistocene led to intermittent land bridges connecting Sicily to mainland Europe and as a consequence Sicilian flora and fauna descend from species arriving from that continent.  The location of the island in the Mediterranean Sea moderated climate, and species that disappeared from most of Europe during severe Ice Ages found refuge on Sicily.  The region is now known for mild wet winters and hot dry summers.  Average annual temperatures were likely slightly cooler during stadials.  Myrtle, oak, and cork trees covered lower elevations, while oak-beech forests occupied higher elevations.  Volcanic mountains and abundant rivers vary the landscape.

Species of large animals living on Sicily during the late Pleistocene included bison, aurochs, horse, fallow deer, red deer, roe deer, wild boar, brown bear, cave lion, hyena, wolf, and giant tortoise.  2 unique species lived on the island then–a dwarf elephant (Palaeoloxodon mnaidriensis) and the dwarf Sicilian hippo (Hippopotamus pentlandi).  The dwarf elephant was closely related to the extant Asian elephant.  It weighed just 3000 pounds, and the species also occurred on the nearby island of Malta.  Both the dwarf elephant and the Sicilian hippo became extinct shortly after man colonized Sicily about 14,000 years ago.

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Artist’s depiction of P. mnaidriensis along with a few swans.  I don’t believe it is drawn correctly to scale, unless this is the depiction of a juvenile.  Dwarf elephants were small but they weren’t this small.

People gradually eroded the quality and quantity of wildlife on Sicily, and they utterly destroyed the natural ecosystems.  Most of the island was deforested during Roman rule, leading to prolonged droughts, and the last wolves were  exterminated during the 1920s.  Though 150 species of birds live on the island, including flamingoes and several species of eagles, many are endangered.  However, the island is home to Nebrodi Mountains National Park where roe deer, wild boar, hares, Eurasian red squirrels, crested porcupines, wild cats, and foxes still roam.  Small towns founded during the Byzantine Empire are scattered throughout the park, and farmers keep rare breeds of horses and black pigs here.  The oldest chestnut tree in the world (more than 2000 years old) grows on Mt. Etna.

I’m going to read a book about the human history of Sicily next and will write a blog article about it when I’m finished.

Reference:

Bofiglo, L. et. al.

“Bio-chronology of Pleistocene Vertebrate Faunas of Sicily and Correlation of Vertebrate Bearing Deposits with Marine Deposits”

Il Quaternario 16 (1BIS) 2003

 

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Pleistocene Microfauna Inherited the Earth

April 8, 2019

The biblical passage “Blessed are the meek: for they shall inherit the earth” always makes me think of the late Pleistocene megafauna extinctions.  The passage is part of Jesus’s sermon on the mount and is found in Matthew 5:5, though for some reason Luke omits it.  Most biblical scholars believe the word meek in this passage means powerless, and it represents the slaves and the small powerless Christian sect within the Roman Empire.  A large segment of the Roman Empire’s population consisted of slaves, and the Christian religion appealed to them because of the concept that their miserable lives might be rewarded in the afterlife, if they believed in Jesus.  Ironically, after the Roman Emperor Constantine made Christianity the official religion of the empire centuries later, Christians no longer acted meek–they oppressed all other religions. The late Pleistocene extinctions make me think of this passage because so many powerful animals such as giant lions, saber-tooths, short-faced bears, dire wolves, mastodons, mammoths, ground sloths, and giant bison all disappeared from the face of the earth; but small animals continued to live and were just as common as they’d always been.  Among them are 2 of the smallest mammals on earth–the southern short-tailed shrew (Blarina carolinensis) and the eastern pipistrelle (Pipistrellus subflavus).

Photo of a short-tailed shrew my cats killed last week.

The southern short-tailed shrew weighs between .5-1 ounce.  They hunt in burrows near the surface but also scurry though more permanent burrows located up to 2 feet underground.  They eat half their own weight in food everyday.  Their diet consists of worms, spiders, centipedes, insects, snails, amphibians, and mice.  During winter they can subsist on fruit, acorns, and fungi.   They are smaller than mice but can subdue them with a venomous bite.  Southern short-tailed shrew specimens have been recorded from at least 23 Pleistocene-aged fossil sites, including the Isle of Hope in southeast Georgia.

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Eastern pipistrelle.

The eastern pipistrelle weighs between .1-.3 ounce and is about the size of a large moth.  Their wingspan reaches a width of only about 2 inches.  They feed upon flying insects.  Both eastern pipistrelles and short-tailed shrews navigate in the dark by using echolocation.  Fossil specimens of this species have been found from at least 19 Pleistocene-aged fossil sites including Ladds in north Georgia.

Of course, not all species that inherited the earth are meek.  Man is a notable exception.

 

New Species of Mastodon (Mammut pacificus) Recognized

April 1, 2019

I didn’t have to search for this science news.  A link to the complete scientific paper appeared on my facebook page last week, and I knew right away this important new study was blog worthy.  Some pundits complain about the way social media intrudes on privacy, but I love how information relevant to my interests is directed to me.  If people are worried about their privacy, they should not go on the internet.

For almost 100 years paleontologists thought just 1 species of mastodon occurred in North America during the Pleistocene.  They believed the American mastodon (Mammut americanum) ranged from coast-to-coast and from the Rio Grande to Alaska.  However, 10 years ago some scientists noticed mastodon skeletal material from the Rancho Labrea Tar Pits in California differed from mastodon bones found elsewhere in North America.  Mastodon bones are relatively uncommon from Rancho Labrea where they are greatly outnumbered by mammoth (Mammuthus colombi) specimens.  Open dry environments prevailed around this site during the Pleistocene–an habitat favored by grass-eating mammoths.  Mastodons were semi-aquatic browsers, preferring to feed upon leaves, twigs, fruit, and wetland vegetation.  Within the last 10 years scientists discovered 700 mastodon bones during construction of the Diamond Lake Reservoir in Riverside County California.  This was enough material for scientists to anatomically compare California mastodons with American mastodons, and they concluded they were indeed 2 different species.

Map showing distribution of 2 mastodon species is from the below referenced paper.  Click to enlarge.  The red dots represent M. pacificus; the blue dots represent M. americanus.  Scientists aren’t sure which species ranged into Oregon.  It’s not a comprehensive distribution map for M. americanus.  I’m aware of 5 additional locations where mastodons were found in Georgia but not represented on this map.  American mastodons were more abundant in eastern North America than western.

Paleontologists named this new species M. pacificus because all specimens of this species have been found within 620 miles of the Pacific Ocean.  Apparently, this species occurred in California, southern Idaho, and possibly Oregon.  Mastodon material found in Oregon is not diagnostic, meaning there is not enough to make a species identification.  All mastodon material north of Oregon (from Washington, the Yukon, and Alaska) belongs to M. americanum, the species found throughout most of North America north of the Rio Grande.

The Pacific mastodon differs from the American mastodon in several ways.  Their molars are smaller and more narrow.  They also tend to have more sacral fused vertebrae. Pacific mastodons had 6, whereas American mastodons usually had 4 or 5 (but sometimes 6).  Pacific mastodons had thicker femurs in proportion to the length of their legs, but their tusks were smaller in diameter.

Geographical barriers likely caused the divergence of these 2 species.  Habitat favorable for mastodons was more scarce in western North America.  High mountain ranges frequently covered by glaciers during Ice Ages, and large deserts separated these 2 species.  Over time the isolated California population evolved into a different species of mastodon.

Reference:

Dooley, A.; et. al.

“Mammut pacificus sp. nov., a Newly Recognized Species of Mastodon from the Pleistocene of Western North America”

Peer J March 2019

2 New Studies of Pleistocene Lions

January 6, 2019

There were 3 species of lions living on earth during the late Pleistocene.  The African lion (Panthera leo) is the only species still extant.  The cave lion (P. spelaea) ranged across Eurasia from Britain to Beringia which included Alaska and Yukon above the Canadian Ice Sheet.  The giant American lion (P. atrox) lived in North America south of the Ice Sheet from California to Florida.  Some taxonomists formerly thought the 3 lions were the same species, but recent analysis of anatomy and genetics determined they were 3 distinct species.

2 new studies of Pleistocene lions were published last year.  The first study described an unusually large lion skull found in Natodermi, Kenya.  This specimen is estimated to be 196,000 years old. On average cave lions and giant American lions were larger than African lions.  P. atrox was the largest species of lion, averaging 25% larger than African lions, and 1 specimen is estimated to have weighed over 1000 pounds.  (See https://markgelbart.wordpress.com/2017/01/31/panthera-atrox-the-1007-pound-giant-lion/ )   However, the specimen described in this new paper (catalogued as #KNM-ND59673) belonged to an individual that may have been larger than any cave lion specimen ever described and even larger than all but 2 known American lion specimens.  The size comparison estimates in this paper were based on dental dimensions.  The authors of this paper believe this individual was part of an extinct population that grew to a larger size because they hunted an extinct species of large buffalo (Syncerus antiquus).  They think it was a subspecies of African lion related to the ancestors of the 2 regional haplotypes of lion that still occur today.  Genetic evidence suggests northern lions diverged from an ancestral population of lions 147,000 years ago, while southern lions diverged 189,000 years ago.  This specimen was found on the border between the 2 modern haplotypes.  Although they don’t think it was a distinct species, they can’t completely rule it out–there just isn’t enough evidence.  It seems likely some Pleistocene African lions were just as large as the other 2 species.  Lions originally evolved in Africa but fossil evidence from that continent is more rare than in Eurasia and North America.

 

196,000 year old African lion skull.

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Pleistocene lions may have grown larger in Africa to help them bring down this large extinct species of buffalo.

The 2nd study described 4 specimens of cave lion found in Medvedia Cave located in the Zapadne Tatry Mountains.  These mountains border northern Slovakia and southern Poland. Referring to this species as the “cave” lion is misleading.  Most individuals never went inside a cave during their entire life.  A cave environment is just 1 of the rare places where their remains could be preserved.  Medvedia Cave is the highest altitude that a lion fossil has ever been found.  The authors of this paper think lions searched through caves for hibernating bears, and groggy bears may have been an important part of high altitude lions’ diets because other substantial prey was scarce here.  Some scientists think cave lions were solitary hunters or perhaps hunted in pairs, unlike social African lions that live in large prides.  I disagree with this notion.  Adult male lions grow too large and bulky to hunt prey effectively, and they depend upon females to bring them food.

Lions were more widespread during the Pleistocene because human populations were sparse.  Humans have outcompeted lions since then.  If not for the rise of humans, lions would still be just as widespread as they used to be.

Reference:

Manth, F. ; et. al.

“Gigantic Lion, Panthera leo, from the Pleistocene of Natodermi, eastern Africa”

Journal of Paleontology 92 (2) Novemeber 2018

Sabol, Martin; Juraj Gullar and Jan Harrat

“Montane Record of the Late Pleistocene Panthera spelaea (Goldfuss 1810) from Zapadne Tatry Mountains (northern Slovakia)”

Journal of Vertebrate Paleontology  38 (3) 2018

See also: https://markgelbart.wordpress.com/2016/01/07/uf9076-a-complete-skull-and-jaws-of-a-giant-lion-panthera-atrox-found-in-the-ichetucknee-river-florida/

There was No Such Species as the Fugitive Deer (Sangamona fugitiva)

December 16, 2018

During 1920 Oliver Hay, a noted paleontologist of that era, named a new species based on a tooth discovered in a Tennessee Cave 35 years earlier.  He believed it was from an extinct species of deer, and he gave it the scientific name of Sangamona fugitive because he thought it may have been common during the Sangamonian Interglacial, though most specimens of this proposed species came from deposits dating to the Wisconsinian Ice Age.  For the next 60 years scientists assigned additional specimens found at fossil sites located in Tennessee, Illinois, Maryland, and Iowa to this species.  The fugitive deer was thought to be a species intermediate in size between a white-tail deer and an elk.  However, during the early 1980s a paleontologist by the name of George Churcher looked at all the specimens assigned to this species and determined they were actually the bones of white-tail deer, elk, or caribou.  Some were from large white-tails and others were from small elk, explaining why they seemed to fall between the range of the 2 species.  Churcher declared Sangamona fugitive an invalid species.  No such animal ever existed.  Taxonomists refer to this as a nomen nudem or naked name because it was assigned to a non-existent animal.

I was unaware of Churcher’s study when I wrote about the fugitive deer in my book and in a few of my earliest blog entries.  His paper is buried in the middle of an obscure special bulletin of the Carnegie Museum.  I did come across this paper a few years ago, but I never felt motivated to write about it until now.  I’m in the middle of researching future topics for my blog and ran into a delay with a couple I had planned, so I finally decided to note this old mistake that originated from a long dead paleontologist.

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Most bones mistakenly assigned to the fugitive deer actually belonged to white-tail deer or elk.

The fossil record suggests there were just 4 species of deer living in southeastern North America during the late Pleistocene.  White-tail deer lived throughout the entire region.  Caribou and the extinct stag-moose (Cervalces scotti) periodically colonized the upper south during cooler climatic stages of the Ice Age.  Elk probably didn’t enter the upper south until 15,000 years ago.  Mule deer may or may not have occurred in western Arkansas.  A single specimen of the South American marsh deer found in Florida was probably a misidentified white-tail deer bone.  (See: https://markgelbart.wordpress.com/2013/02/28/sabertooth-cave-in-citrus-county-florida/ )

Reference:

Churcher, George

“Sangamona: the Furtive Deer”

Bulletin of the Carnegie Museum: Contributions in Memorial to John Guilday 1984

ABC Bears

November 5, 2018

During the Ice Age the coast of southeast Alaska was studded with ice floes and perfect habitat for seals and polar bears.  The interior of Alaska was mostly grassy steppe, the preferred habitat of brown bears.  About 16,700 years ago the icy habitat along the southeast coast of Alaska began to melt and polar bear populations became stranded on Admiralty, Baranet, and Chichagof Islands; also known as the ABC islands.  Here, the habitat began to become more favorable for grizzly bears, and young males looking for new territory not already occupied by adult males colonized the islands.  A genetic study of 1 specimen from this island group determined these colonizing male brown bears mated with female polar bears, creating an hybrid population  (Ursus arctos x U. maritimus).  Gradually, the population of brown bears swamped the DNA of this region, so today polar bear DNA makes up just 6% of their X  chromosome (the female chromosome is XX; the male is normally XY).  Polar bear DNA has also been found in specimens of the extinct Irish brown bear.  DNA evidence suggests polar bears diverged from brown bears about 4 million years ago, but there has been periodic hybridization in regions where the 2 species overlap.

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Location of the ABC islands.

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Top 2 photos are polar bear/brown bear hybrids in captivity.  Bottom right is a polar bear; bottom left a brown bear.  The 2 species rarely do hybridize in the wild.

A few months ago, Discovery Channel aired a program about the ABC bears that I lambasted in this blog article https://markgelbart.wordpress.com/2018/06/04/the-fear-island-special-that-aired-on-animal-planet-last-night-was-full-of-shit/ .  Previously, Discovery Channel has aired programs about Bigfoot, mermaids, and the extant existence of a 60 foot long extinct species of shark.  I assumed this program was completely bad pseudo-science, but 1 of my readers alerted me to the scientific merits of this program and also informed me that I wrongly assumed the ABC islands were the same as the Kodiak islands.  The Kodiak islands are on the other side of the Gulf of Alaska, so I errored geographically by hundreds of miles.  And the expedition on this program did have scientific merit because they were seeking just the 2nd DNA sample from an ABC bear.  However, I still think this program was full of shit…just not as full of shit as I initially assumed.  Here is why I stand by my first opinion:

1. The participants acted as if they were the first researchers to ever obtain DNA evidence from a bear on the island, though a study of 1 specimen had already been published.  They already had a good idea what they were going to find, and it was not a great mystery as they promoted.

2. The Indian guide claimed he saw 6 bears ceremonially bury another dead bear.  What unscientific bull crap.

3. I don’t buy the size estimate claim.  It was based on an up close trail cam photo.  Weigh it or just shut up.

Reference:

Cahill, J; et. al.

“Genetic Evidence for Island Populations Conversion Resolves Conflicting Theories of Polar Bear Evolution”

PLOS Genetics 2013

 

Pleistocene Pine Voles (Pitymys pinetorum)

October 16, 2018

Evolutionary biologists like to study rodent fossils.  Rodents occur in high population numbers, and their rapid generational turnover means evolutionary change occurs faster than with larger slower breeding animals.  Scientists recently studied pine vole teeth from 2 caves in Kentucky and 1 cave in Georgia that date to the last Ice Age and compared them with modern day pine vole teeth.  Pine vole teeth from Hilltop and Cutoff Caves in Kentucky date to about 30,000 years ago, and the pine vole teeth from Yarbrough Cave in Georgia date to about 23,000 years ago.  Pine voles are still a common species, occurring all across eastern North America.  Despite their name, they prefer living in moist deciduous forests where they tunnel under tree roots and feed on roots, seeds, fruit, fungus, and insects.  Their fossorial existence keeps them safe from owls and hawks, though snakes can enter their burrows.  Pine voles are considered arvicolid rodents because their teeth cusps are in the shape of alternating triangles.  Other common arvicolid rodents include meadow voles, lemmings, muskrats, and cotton rats.

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Pine voles weigh just an ounce.  They mostly live underground but occasionally venture to the surface.

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Pine vole range.  Pine vole is a misnomer.  They prefer moist deciduous woods, not pine forests.  Nobody knows why the common name is pine vole.

The pine vole teeth from the Kentucky Caves show the pine voles living then were the same size as modern day pine voles living in the region.  However, pine voles living in north Georgia during the Ice Age were larger than modern day Georgia pine voles and about the same size as northern pine voles.  Scientists believe this was in response to colder temperatures.  Bergmann’s rule states that animals living in colder climates generally grow to a larger size because they are better able to retain body heat.  The authors of this study can’t determine whether this large size was the result of inbreeding with northern populations of larger pine voles that colonized the region or natural selection of the local population.

Reference:

Martin, Robert; and K. O’Bryan

“Size and Shape Variation in the Late Pleistocene Pine Vole (Mammalia: Arvicolidae: Pitymys Pinetorum) First Lower Molars from 3 Caves in Kentucky and Georgia”

Paludicola September 2014

A New Study of the Looper Collection

October 9, 2018

Between 1989-1995 Lonnie and Freida Looper hunted for fossils on 19 different gravel bars along the Mississippi River during droughts when the bars became exposed.  These gravel bars are located between Helena, Arkansas and Greenville, Mississippi.  Thousands of years ago, the bones were quickly buried when glacial meltwater pulses flooded the Mississippi River Valley.  The Mississippi River erodes this Pleistocene-aged sediment and deposits the soil and bones on the gravel bars.  For years the Looper family sold replicas of their specimens, but they donated most of the actual specimens to Delta State University.  I don’t think they still sell the replicas, though the Looper’s website remains on the internet.  The Looper family discovered over 550 specimens including 27 species.  A comprehensive study of their collection wasn’t published until 2017.

 

 

 

 

 

 

The Looper family found this Jefferson’s ground sloth claw on a Mississippi River gravel bar exposed during a drought.

During most of the late Pleistocene the Mississippi River entered the Mississippi River Valley through 3 gaps, but all of these flooded following the collapse of the ice dam that unleashed the waters of Lake Agassiz about 12,900 years ago.  Before this the Mississippi River didn’t meander broadly like it does today.  Instead, it was a series of braided channels clogged with sandbars because the water table was much lower then.  Cold glacial meltwater pulses caused cool microclimates within the valley that favored mixed Ice Age woodlands of pine, spruce, ash, aspen, oak, hickory, willow, tamarack, herbs, and grass.  Frequently flooded bottomlands and abandoned dried-out channels hosted alder thickets with beech, walnut, tulip, willow, and grass.  Spruce and jack pine dominated drier upland sites.  These were the types of habitats that supported the animal life represented in the Looper collection.  Some of the species they found were not known to have occurred within the Mississippi River Valley including paleolama, stag-moose, helmeted musk-ox, giant short-faced bear, and manatee.

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Map of the Mississippi River Valley in relation to the ice sheet during the Last Glacial Maximum. This map doesn’t represent the land area that occupied the continental shelf then.

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The Mississippi River resembled this modern day braided river during the Ice Age.

Paleolama mirifica was a species known from the coastal plains of South Carolina and Georgia, and throughout Florida; so the specimen found by the Looper family was a first for the region and evidence for a greater range than was previously known. The manatee was likely an accidental migrant that may have perished because it failed to go south during cool weather.  Manatees can’t survive in water temperatures below 68 degrees F.  The Looper family also collected bones of mammoth, mastodon, bison, white-tailed deer, long-nosed peccary, 2 species of extinct tapir, horse, beaver, giant beaver, Jefferson’s ground sloth, dire wolf, raccoon, black bear, giant tortoise, snapping turtle, soft-shelled turtle, unidentified bird, small-mouth buffalo fish, and flat-headed catfish.  Bones of bison and deer were the most common.

Nina Baghai-Riding, the lead author of this new study, thinks the Mississippi River Valley may have been a migratory corridor for some species.  Cool microclimates along the river may have attracted fauna of northern affinities.  Rivers are also rich in food resources as well because a greater quantity and quality of vegetation can grow in more irrigated environments.  The superior feeding opportunity attracted megafauna as well.

Reference:

Baghai-Riding, Nina; and D. Hunley, C. Beck, and E. Blackwell

“Late Pleistocene Megafauna from Mississippi Alluvium Plain Gravel Bars”

Paludicola December 2017

file:///C:/Users/Owner/AppData/Local/Packages/Microsoft.MicrosoftEdge_8wekyb3d8bbwe/TempState/Downloads/Baghai-RidingLatePleistocenegravelbarpaper%20(3).pdf

 

How far South did the Extinct Stag-Moose (Cervalces scotti) Range During the Late Pleistocene?

October 2, 2018

A species of extinct deer, slightly larger than a modern day moose (Alces alces), occurred south of the ice sheets during the late Pleistocene.  It is alternatively known as stag-moose or elk-moose, but its scientific name is Cervalces scotti. This giant deer had the long nose of a moose, though its antlers were more like those of an elk.  However, it shared a closer common ancestor with the former.  They inhabited wetlands surrounded by mixed forests dominated by spruce but with significant elements of pine and hardwoods.  Like modern day moose, they fed upon aquatic plants during summer and twigs during winter.  Mastodons occupied a similar habitat and fed on the same foods, so the 2 species often co-occurred together.

Evidence from the fossil record suggests stag-moose were particularly abundant in midwestern bogs left by retreating glaciers.  Stag-moose bones are quite commonly found in Ohio, Indiana, Illinois, and New York.  Surprisingly, they occurred even farther south with isolated fossil remains having been discovered in Virginia, Arkansas, Mississippi, and South Carolina.  The stag-moose remains found in Desha and Philips County, Arkansas and Rosedale, Mississippi are at 34 degrees latitude.  These consist of antler fragments and a jawbone with a tooth.  The stag-moose specimen from Charleston, South Carolina (just a tooth) occurred at 32 degrees latitude.  This is probably close to the southern limits of its former range because stag-moose remains are completely absent from sites in fossil rich Florida.

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Artist’s depiction of the stag-moose.  They were huge. That is a lot of venison.

A stag-moose skeleton found in Chippewa Lake, Medina, Ohio had 1 bone that had attached sediment filled with pollen representing the type of environment it lived in.  The pollen included fir, maple, alder, aspen, birch, hickory, hackberry, hazelnut, ironwood, pine, oak, basswood, elm, spruce, cedar, ragweed, grass, and cattail.  Spruce pollen made up 60% of the total.  It seems likely the type of environment favored by the stag-moose, as far south as Charleston, South Carolina, included various compositional ratios of these species.  I hypothesize stag-moose occurred in the mid-south during cool moist interstadials rather than the coldest driest stages of Ice Ages.  Wetlands would’ve been more common during these climatic phases.  Full blown glacial maximums restricted stag-moose habitat because desert scrub and grassland habitat expanded then.

Although there is no supporting archaeological evidence, I think overhunting by humans caused the extinction of the stag-moose.  Man colonized North America when ice sheets covered most of Canada, thus restricting stag-moose to more temperate regions where humans became common enough to impact their populations.  When the glaciers began to recede, optimal stag-moose habitat increased, but humans had already decimated their populations into extinction.  Modern day moose crossed the Bering land bridge, and ecologically replaced the stag-moose and were able to survive in northern latitudes where human populations remained too scarce to overhunt them.

Reference:

Mcdonald, Greg; R. Glotchober

“Partial Skeleton of an Elk-Moose, Cervalces scotti, from Chippewa Lake, Medina County Ohio”

Research Paper 2017

Were Beringian Wolves Blonde?

September 25, 2018

An extinct ecomorph of the gray wolf (Canis lupus) roamed North America from Beringia to at least as far south as Wyoming during the Late Pleistocene. (See: https://markgelbart.wordpress.com/2016/05/30/beringian-wolves-an-extinct-ecomorph-of-canis-lupus-lived-as-far-south-as-wyoming/ ) Beringia included the unglaciated region of Alaska, the Yukon, and the Bering Strait located north of the Ice Sheet that covered most of Canada then.  The Bering Strait emerged above sea level during Ice Ages.  An ecomorph is the regional variation of a species that differs morphologically from other populations of the same species.  Beringian wolves had bodies closely resembling those of gray wolves, but their teeth and jaws were larger and more robust like those of the extinct dire wolf (C. dirus).  Paleontologists interpret the larger teeth and jaws as an adaptation for preying and scavenging on megafauna.  Isotopic evidence of Beringian wolf bones does suggest they fed upon mammoths, horse, bison, musk-ox, and caribou.  Beringian wolves were not ancestral to modern day Alaskan gray wolves, but they do share a common ancestor.  Genetic evidence suggests Beringian wolves diverged from wolves found in northern China and Mongolia today about 28,000 years ago.  Present day Alaskan wolves descend from a different population of wolves than the Beringian wolves which became extinct about 7500 years ago.

Map showing location of sites where Beringian wolf bones have been discovered and the proposed route from Beringia to Wyoming.  I hypothesize they occurred as far south as the southern Appalachians.

I hypothesize Beringian wolves were an hybrid species originated when gray wolves interbred with dire wolves.  This hypothesis will be possible to test when scientists are able to extract DNA from a dire wolf fossil.  There are thousands of dire wolf specimens from the La Brae Tar Pits, but the tar in the bones prevents DNA extraction.  Many specimens of dire wolf have been found in Florida as well, but humid conditions here cause DNA to deteriorate.  I also hypothesize Beringian wolves were more widespread than the fossil record indicates.  Over much of the continent fossil evidence of canids consists of isolated teeth and bones difficult for scientists to differentiate between gray wolf, Beringian wolf, dire wolf, and even large Pleistocene coyote.  For example 1 wolf tooth found at Ladds Cave in north Georgia was identified as belonging to a gray wolf by 1 paleontologist, but another scientist ruled it fell within the size range of a dire wolf.  Maybe this specimen came from a Beringian wolf.

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80,000 year old mummified wolf pup found in a Yukon gold mine.  Note the coat color.  It’s is a brownish blonde.

During June of 2016 gold miners discovered the mummified remains of a wolf pup.  As the photo shows, it was perfectly preserved.  Carbon dating of the specimen indicated it was older than 50,000 years–the upper limit of carbon dating.  However, the specimen was associated with volcanic ash dated to about 80,000 years BP.  This predates the 28,000 year old divergence between Mongolian wolves and Beringian wolves, so it will be interesting to learn how this specimen relates to later populations of wolves.  Julie Meachen of Des Moines University will lead a study of the pup.

The coat color of this specimen surprises me.  Of all the speculative illustrations of Pleistocene wolves none depict a golden, blonde, or tawny colored coat.  This specimen appears to have a coat color similar to a lion but a little darker.  Perhaps preservation in permafrost for so long changed the original color of the coat but suppose this was the color.  The coat color likely resembled the landscape background of its habitat.  Patches of yellow grass interspersed with bare dirt predominated in Beringia and much of North America during Ice Age stadials when precipitation was scarce and temperatures dropped.  It’s possible packs of yellow dire wolf/gray wolf hybrids lived throughout parts of North America for thousands of years.