Did the dhole (Cuon alpinus) range into southeastern North America during the Pleistocene?

Photo of dholes from google images.

John Valliant sets the scene in his excellent non-fiction book, The Tiger, with a description of Russia’s far eastern flora and fauna.  Of the latter he mentions the dhole (Cuon alpinus), a medium-sized canid that no longer exists where Siberian tigers now roam, but still clings on to its last strongholds in India and a few neighboring countries.  Upon reading this, I remembered Bjorn Kurten’s brief account of dhole fossils found in North America.  In Pleistocene Mammals of North America he stated that dhole fossils were found in at least 3 sites in Alaska and 1 in Mexico. This means the species existed throughout the center of North America and perhaps in other regions as well.

Richard Reynolds, formerly curator of the Los Angeles Museum of Natural History, first identifed 7 specimens (lower jaws and teeth) of dholes that were excavated from San Josecito Cave in northeastern Mexico.  In 1971 Ronald Nowak examined the specimens and confirmed that they were from dholes.  Dr. Nowak is the world’s foremost authority on Pleistocene canids.  However, the specimens weren’t described in the scientific literature until 2009, and scant attention was paid to the role dholes played in North American ecology.  I can remedy that, at least on my blog.

Map of location of San Josecitos cave, and a photo of early excavation at the site.  From “The Cave of San Josecito Mexico: New Discoveries of the Vertebrate Life of the Ice Age” by Chester Stock in Engineering and Science Monthly (circa 1940?).

Map of ecological corridors from Mexico to the rest of North and Central America.  During the Ice Age when dholes were present, mixed pine forests displaced what’s now xeric scrub.  Dholes could have colonized the southeast from the gulf lowland corridor.  From “Effects of Pleistocene Environmental Changes in the Distribution of Community Structure of the Mammalian Faunas of Mexico” by Gerardo Ceballos; et. al. in Quaternary Research 73 (2010) page 470.

I think it’s quite possible dholes periodically colonized parts of southeastern North America but without fossil evidence, there is no way of knowing for sure.  Their preferred habitat is montane forests of about 3000 feet in elevation, though they can adapt to steppe-like environments, and jungles.  The mixed forests in the piedmont and mountain regions of what’s now Mississippi, Alabama, Georgia, Tennessee, and the Ozarks of Arkansas would have been ideal and potential habitat for them.  They must have found a suitable corridor of habitat along the Rocky Mountains because they found their way from Alaska to Mexico.  Despite the lack of fossil evidence, they must have inhabited the  region in between.  How far east they ranged is unknown. Florida’s rich fossil record draws a blank for dholes.  However, Florida’s fossil record also draws a blank for red wolves (Canis rufus).  It’s likely red wolves were regionally present in low numbers during the Pleistocene because they became the dominant canid here following the extinction of dire wolves.  Moreover, collared peccary and giant short-faced bear (Arctodus simus) fossils weren’t known from Florida until within the last 5 years, so dhole fossils may yet be discovered somewhere in the southeast.  As the old chiche` goes, absence of evidence is not evidence of absence.  There may be evidence  from Georgia–a tibia from a medium-sized canid was excavated from Kingston Saltpeter Cave in Bartow County.  Unfortunately, scientists require skulls and teeth to determine canid species.  The tibia could be from a dhole…or a coyote, a juvenile wolf, or even a paleo-indian’s dog.

One further note on the absence of dhole fossils in the southeast–the odds of an individual animal becoming a fossil are unknown but may be 1 in a million.  900,000 dholes could have lived in the region over the millenia, but that number wasn’t high enough to significantly increase the chances of one of them becoming a fossil.

How did dholes interact with North America’s Pleistocene fauna?  Dholes live in packs of 10-12 but sometimes multiple packs temporarily merge forming groups of up to 40.  Despite including individuals only weighing 25-40 pounds, these expanded packs have been reported to successfully attack large buffaloes and even tigers.  The packs do suffer considerable mortality when battling these ferocious foes.  A tiger can kill a dhole with just a blow from its paw.  Perhaps, dholes occasionally attacked saber-tooths.  Maybe that’s why they’re not common in the fossil record–saber-tooths may have dispatched a whole foolhardy pack.  Dholes are less intelligent than wolves. 

Dholes may on occasion attack large dangerous prey, but one study found that their preferred prey selection was of individuals weighing between 60-350 pounds, and the average kill weighed 86 pounds.  Deer, peccary, juvenile horses, and bison calves would’ve been their preferred prey in North America.  By comparison, in that same study, the average kill of a tiger was 180 pounds.  So dholes probably selected for smaller prey than dire wolves, saber-tooths, scimitar -tooths, jaguars, and giant panthers (Panthera atrox), and thus occupied a slightly different ecological niche.

In a correspondence with Dr. Nowak I suggested that, based on their rarity in the fossil record, dholes didn’t compete well with dire wolves.  He thinks it was competiton with timber wolves (Canis lupus) that may have kept their numbers low here and possibly caused their extirpation on the continent.  However, I hypothesize that it was the extinction of the megafauna, not interspecific competition, that led to their demise in North America and Europe.  The existence of large amounts of meat in the form of mammoths, mastodons, and giant ground sloths was a boon to carnivores and scavengers.  Though dholes didn’t actively hunt them, when one of these great beasts died a natural death, they provided a feast for predators of all kinds, contributing to an increase in their survival rate and diversity.

I can just imagine a pack of quick dholes aggravating a saber-tooth or giant bear until they abandoned the carcass.  But today, dholes only survive in ever shrinking territory.  It would be a shame to lose them.

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San Josecito Cave

San Josecito Cave is a spectacular fossil site, eighty feet in depth.  The matrix originally excavated was 60 feet thick in fossils.  Scientists  are still excavating the site, even though excavation began in the 1930’s.  At least 62 species of bird fossils have been found here.  Here’s a partial list of species found at the site.  * denotes extinct species.

*Shasta ground sloth

*Jefferson’s ground sloth

dhole

coyote

gray wolf

*dire wolf

cougar

*saber-tooth

*giant panther–Panthera atrox

jaguar

black bear

*Florida spectacled bear

hog-nosed skunk

vampire bat

southern bog lemming

pocket gopher

yellow bellied marmot

cottontail rabbit

Sylviligus leonensis–an extinct species of rabbit

*mountain deer–Navahoceras fricki

white-tail deer

*llama

horse

*an extinct species of pronghorn–Stockoceras conklingi

*an extinct subspecies of mountain goat–Oreamnos harringtoni

*walking eagle

golden eagle

*Grinnell’s Crested eagle

white-tailed kite

Harris Hawk

Gray Hawk

Ferriganous hawk

red-tailed hawk

northern harrier

prairie falcon

*terratorn

black vulture

California Condor

*a large extinct vulture–Neogyps errans

*a small extinct vulture–Neophrontops americanus

*a large extinct subspecies of roadrunner

turkey

Montezuma quail

wood quail

band-tailed pigeon

mourning dove

pied-billed grebe

wood duck

ruddy duck

dabbling duck

harlequin duck

king rail

Virginia rail

coot

*an extinct stork–Ciconia

pinyon jay

scrub jay

raven

woodcock

thick-billed parrot

maroon-fronted parrot

pygmy owl

elf owl

saw-whet owl

great horned owl

spotted owl

barn owl

eastern screech owl

whiskered screech owl

long-eared owl

short-eared owl

plover

common poorwill

robin

black crowned night heron

curlew

meadowlark

red-shafted flicker

Tags: dhole, dhole fossils in North America, Richard Reynolds, Ronald Nowak