Seals and Walruses off Southeastern North America’s Pleistocene Coast

Scientists expressing concern about anthropogenic global warming always seem to ignore paleontological evidence.  There is no better example of their alarmist approach than the oft-stated fear that global warming might cause the extinction of arctic marine mammals.  Yet, during the Sangamonian Interglacial (~132,000-~118,000 BP) the north polar ice cap completely melted, and there are no known extinctions of arctic marine mammals when this occurred.  Pleistocene ranges of seals and walruses were greatly expanded compared to the extent of where they live now.  And during both cold and warm climate cycles marine mammals occurred much farther south than they do today.  It’s more likely that their ranges are more limited today due to anthropogenic overhunting rather than changes in climate.  Evidence of my above-stated observation comes from fossils of seals and walruses found off the coast of South Carolina.

Gray Seal–Halichoerus grypus

Photo of gray seal from google images.  This species occurred at least as far south as South Carolina during the Pleistocene.  Now that they’re protected, it’s believed their range will expand farther south than New Jersey once again.

Fossils of this species have been found on Edisto Beach, South Carolina.  Until the Marine Mammal Protection Act of 1972, bounties kept the population of gray seals low, reducing them to 2,000 individuals on the North American side of the north Atlantic.  Since then, the population has expanded south to New Jersey where they frequently resort during winter.  They’re expected to spread even further south and may some day recolonize South Carolina.  They eat fish, lobster, and octopus.

Hooded Seal–Erignathus barbatus

Hooded seal from a picture at google images.  Man are they ugly.  The balloon on the males’ nose is used to attract mates.

Hooded seal flipper bone fossil found off the South Carolina coast.  All the pictures of fossils in this blog entry are from Additions to the Pleistocene Mammal Fossils of South Carolina, North Carolina, and Georgia by Albert Sanders.

The above fossil flipper bone was recovered in Horry County, South Carolina and is believed to be Sangamonian in age.  This solitary species mostly occurs in the arctic but is known to wander widely and has been reported in modern times as far south as the Carribbean.  Perhaps this specimen belonged to one such straggler.

Walurs–Odobenus romarus

Photo of a walrus from google images.

Fragments of walrus tusk fossils  discovered off the coast of South Carolina.

At least 6 fragments of fossil walrus tusks have been recovered from sites near Charleston, South Carolina, proving this species lived in the southeast long ago.  Moreover, one amateur fossil collector reports finding a walrus fossil in Florida.  Other walrus fossils turned up in North Carolina and Virginia, so at one time they must have been frequent visitors to southern beaches.  Most of the walrus fossils are assumed to be from a warm interglacial age because they’re found near the present day coast.  During glacial times, the Atlantic coast was many miles to the east of the present day coast due to the drop in sea level during the Ice Age.  I have no doubt walruses are solely limited to arctic regions today because of the remote geography where they’re difficult for human hunters to access.

Walruses mostly eat marine worms and molluscs which they find on the ocean floor with their whiskers.  Male walruses occasionally kill or scavenge and eat seals.  This behavior is probably related to high testosterone levels, much like male elephants that go on a rampage when they’re in the mood to mate.

Monk Seal–Monachus tropicalis

It’s sad to think that this is the only evidence left of a species once frequenting Georgia’s coast.  It’s a vertebrate of a monk seal.

Man hunted this warm climate seal into extinction by 1952.  It’s last reported sighting was off the coast of Jamaica.  It was last reported off the coast of Texas in the 1930’s.  One fossil collector  found bones of a monk seal on Andrews Island near Brunswick, Georgia, and others have found them at many sites off the coast of South Carolina.  What a shame the species couldn’t make it to 1972 when the Marine Mammal Protection Act passed.

Reference

Sanders, Albert

Additions to the Pleistocene Mammal Faunas of South Carolina, North Carolina, and Georgia

American Philosophical Society 2002

Tags: Additions to the Pleistocene Mammal Faunas of South Carolina, Albert Sanders, and Georgia, anthropogenic global warming, Erignathus barbatus, extinction, gray seal, Halichoerus grypus, hooded seal, Monachus tropicalis, monk seal, North Caralina, Odobenus romarus, Sangamonian Interglacial, walrus