Pleistocene Georgia’s Javelinas

Hernando De Soto brought the first pigs (Sus scrofa)  to Georgia in 1540, releasing them in the wild where they could feed on the mast and provide a ready food source.  He also offered them as gifts to Indians on a line from the southwestern corner of the state to the area of what’s now Augusta.  Diseases from pigs, such as influenza and trichinosis, may have wiped out many Indian tribes.  Feral pigs from hunters introducing wild boars and escaped farm-raised individuals interbred and now are overrunning much of Georgia.

Map from the Georgia Department of Natural Resources

Feral hogs

This is evidence that an ecological niche for a pig-like animal still exists in Georgia, and it suggests that some time late in the Pleistocene, Indians must have overhunted peccaries into extinction.  Otherwise, they would still be here because feral hogs sure thrive in state today.

Georgia’s Pleistocene Peccaries

Illustration of long-nosed peccary (top) is from the Illinois State Museum.  The replica of the flat-headed peccary (bottom) is from the Cincinnati Museum.

There were at least three kinds of peccaries (or javelinas) living in what’s now Georgia during the Pleistocene.  By far, the most common species was the long-nosed peccary (Mylohyus nasatus).  Fossils of this animal have been excavated in Bartow County from three different caves and from the Isle of Hope site along the coast.  In Georgia fossil specimens of Mylohyus are almost as common as those of white-tail deer and in fossil sites from south Florida and Arkansas it even outnumbers deer.  They inhabited forested areas, feeding on acorns, roots, and other forest mast.  They probably fed on deer fawns and turkey eggs, like modern feral hogs do.  It exhibited an odd body shape for a pig-like animal, resembling a deer more than a javelina.

A second species of peccary from Georgia’s Pleistocene was the flat-headed kind (Platygonus compressus).  Shaped more like what would expect of a javelina, it preferred dry brushy habitat, similar to that inhabited by a closely related extant species, the Chacoan peccary (Catygonus wagneri), now found in a small area along the border of Paraguay, Bolivia, and Argentina.  Flat-headed peccaries occupied Georgia’s sandhills and dry forests, habitat which expanded during the frequent dry climate cycles that struck the southeast during the Ice Age.  Though far less common here than the long-nosed peccary, their fossils are consistently found in Georgia, South Carolina, and Florida fossil sites.

A third, still extant species, the collared peccary (Pecari tajacu) probably lived in south Georgia during warm climate phases.  Their fossils are exceedingly rare in Florida’s abundant sites and are associated with species of mammals that required frost-free climate, such as Eremotherium and glyptodonts.  Only three sites in Florida yielded remains of this species, including one in the Suwanee River only about 50 miles from the Georgia border.  During warm interglacials collared peccaries expanded their range throughout the south but were never as common as the other two.

Why do feral hogs thrive now where Pleistocene peccaries became extinct?

The answer is simple: litter size.  Collared peccaries have only 1-4 young.  Until protected by game laws, they were in danger of extinction in some regions.  Chacoan peccaries have an average of 2.4 young per litter.  Pleistocene peccaries probably had the same small litter sizes.  By contrast, feral hogs can have up to 13 piglets in a litter.  Wild boars evolved on the same continent as man.  To survive human hunting pressure, individuals that produced greater young had a better chance of passing on their genes–a kind of evolutionary selection.  Moreover, after humans domesticated pigs, for obvious economic reasons, we artificially selected individuals that produced more young–in a way, creating a Frankenstein-like monster.  Once they escaped back into the wild, wild hogs were able to overcome human hunting pressure by reproducing rapidly.

The differences between true pigs and peccaries.

This is from the National Park Service site devoted to Big Bend National Park where a good population of collared peccaries lives.

……………………Peccaries…………………………..Pigs…………………………………..

Has 3 toes on hind foot……………………………..Has 4 toes on hind foot……….

bones fused in the foot………………………………Bones in foot not fused……….

lower arm bones are fused…………………………lower arm bones not fused….

38 teeth………………………………………………….34-44 teeth………………………

canine teeth are straight……………………………canine teeth are curved………

have scent glands……………………………………..lack scent glands………………

have a complex stomach……………………………have a simple stomach………

lack a gall bladder……………………………………..have a gall bladder……………

have a short tail…………………………………………have a long tail………………..

lack sweat glands………………………………………..have sweat glands…………..

References

Hulbert, Richard C.; Gary Morgan and Andrea Kervin

“Collared Peccary (Mammalia, Artidodactyla, Tayassuidae, Pecari) from the late Pleistocene of Florida”

Museum of Northern Arizona Bulletin 65

www.nps.gov/bibe/naturescience/javelina.htm

www.wildlifemanagementinfo/files/wild_hogs_4.pdf

Yahnke, Christopher; et. al.

“The Specific Fecundity, litter size, and sex ration in the Chacoan Peccary (Catagonus wagneri)”

Zoobiology  16: 301-307 1997

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