How Far South did Polar Bears (Ursus maritimus) Range During the Ice Age?

Almost the entire present day range of the polar bear was uninhabitable for this species during most of the Ice Age.  The ice was too thick then, even for species adapted to arctic conditions.  Polar bear ranges shifted south.  Favorable habitat existed between the mile high Laurentide Ice Sheet and the Atlantic Ocean, and polar bears likely wandered along a strip of the Atlantic Seaboard now submerged by rising sea level.  I hypothesize they occurred as far south as what today is the continental shelf off the coast of South Carolina.

Map of North America during the Last Glacial Maximum.  Polar bears probably ranged on a narrow strip of the Atlantic Seaboard off the coast of what’s now Nova Scotia and Maine to as far south as what today is South Carolina during the height of the Ice Age.  Note the narrow strip of land between the ice sheet and the ocean in the northeast.  Dry land extended well off the modern day shoreline.  During warm climate pulses, icebergs broke off and drifted as far south as off the coast of Pleistocene South Carolina.

The ranges of walruses and 5 species of seals were also shifted south by the massive ice sheet.  All of these marine mammals lived on the narrow strip of land between the ice sheet and the ocean from what today is Nova Scotia south to New Jersey where the ice sheet terminated.  Fossils of 3 species have been found even further south near the South Carolina coast–walrus (Odobenus rosmarus), gray seal (Halichoreus grypus), and bearded seal (Erignathus barbatus).  It should not be surprising, if some day, a fossil hunter finds the remains of Pleistocene age harbor seal (Phoca vitulina) or harp seals (Pagophilus groenlandicus) farther south than their present day ranges.  (Harbor seals were probably more abundant off Pleistocene South Carolina’s coast than walruses, despite the absence of the former in the local fossil record.)  Predators follow prey.  Polar bears feed upon walruses, seals, washed up whale carcasses, sea birds, sea bird eggs, and fish.  All of these resources would have been abundant even further south than Pleistocene South Carolina.  One particular rocky outcropping that would have provided ideal nesting habitat for millions of sea birds existed on the Pleistocene coast of South Carolina.  (See: https://markgelbart.wordpress.com/2014/08/14/bulls-scarp/).  I’m certain this site attracted polar bears.  I think the presence of prey species such as walruses and seals in the fossil record of South Carolina means the presence of polar bears can be inferred.

Video of polar bear slaughtering a walrus.  I doubt ice ever grew this thick in South Carolina, even during the Ice Age.  Walruses were not confined to cold regions prior to the  catastrophic increase in the population of humans.

Predators are less common in the environment than prey animals, and therefore are less likely to be preserved as fossil remains.  Moreover, the southernmost range of the polar bear was restricted to the South Carolina continental shelf, an area now deeply submerged under ocean water.  This explains why polar bear fossil remains have yet to be found in this region.  Polar bear fossil remains dating to the Pleistocene are rare worldwide because much of their habitat during Ice Ages is now submerged.  Some day, a trawler dragging the sea bottom may luckily snag a polar bear specimen well south of the species’ present day range.

Polar bears did occur within historical times at least as far south as Great Breton, Nova Scotia.  In 1534 Jacques Cartier and his French crew of explorers encountered a polar bear on Funk Island, located near the mouth of the St. Lawrence River.  They had embarked on the island to collect now extinct great auks (Pinguinus impenns) and other sea birds for the ship’s larder.  The polar bear was also on the island to feast upon sea birds.  (Bulls scarp, the now submerged rocky outcropping off the coast of South Carolina, would have offered similar habitat.)  The surprised bear jumped back into the ocean.  But the following day, the Frenchmen spotted the bear again.  They manned a longboat, pursued the swimming bear, and dispatched it.  Captain Cartier pronounced the meat as good as that of a “2 year old heifer.”  Fresh meat was a treat after a long sea journey’s fare of heavily salted protein.

Pleistocene polar bears probably didn’t wander far inland.  A report of a polar bear fossil found in Breck Smith Cave, Kentucky about 100 years ago is likely a misidentification, and unfortunately that specimen has been lost.  Polar bears are adapted to hunting seals and scavenging whales, so their range hugged the shoreline where they could find their favorite foods.

Just contemplate the diversity of bears that existed in southeastern North America during the Pleistocene.  15,000 years ago, a paleoindian journeying from west Texas or Kentucky to the Atlantic Coast could have possibly encountered grizzly (Ursus arctos), black (Ursus americanus), spectacled (Tremarctos floridanus), giant short-faced (Arctodus simus) and polar bears. I’m 52 years old and have never seen a live wild bear of any kind in person.  The loss of wild lands that support this diversity of bears saddens me.

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2 Responses to “How Far South did Polar Bears (Ursus maritimus) Range During the Ice Age?”

  1. George Crawford Says:

    Reblogged this on BLACKWATER LOCALITY #1 and commented:
    Interesting thoughts about Polar Bear ranges in the Late Pleistocene.

  2. markgelbart Says:

    Thanks.

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