Posts Tagged ‘Ladds Mountain’

When did the Fisher (Martes pennanti) Last Roam the Wilds of Georgia?

January 6, 2012

Another interesting mammal with northern affinities that used to range into what’s now Georgia is the fisher (Martes pennanti).

I found this photo of a fisher carrying a dead squirrel on google images but I think it’s from the cover of an issue of the Journal of Heredity.   They had an article about genetic bottlenecks of this species created from habitat fragmentation.  Fishers require complete forest cover and avoid open fields.

Fossil evidence of fishers in Georgia comes from Ladds stone quarry in Bartow County.  Ladds is a collapsed and eroded cave system that yields fossils of warm climate species such as giant tortoise, Florida muskrats, and rice rats; and c0ol climate species such as bog lemmings and meadow jumping mice, besides the fisher.  The warm and cool climate species may or may not have occurred during the same climate phase–the quarry operation may have mixed fossils of different ages together.  But asymmetric compositions of species are common in most other Pleistocene fossil sites, so no one is really sure.  The fossils found here are at least 10,000 years old.  I suspect they date to the Sangamonian Interglacial–more than 100,000 years ago for reasons I discuss in my blog entry, “The Giant Chipmunk (Tamias aristus).  Kicked up Version of the Eastern Chipmunk?” https://markgelbart.wordpress.com/2011/01/20/tamias-aristus-the-extinct-kicked-up-version-of-the-eastern-chipmunk/

The fossil material of the fisher found at Ladds consisted of a couple of fragments of cheekbone with teeth attached and a partial jawbone.  This proves that fishers occurred in Georgia thousands of years ago during the Pleistocene.  What is not known for sure is how recently they lived in state.  There is fossil evidence of both porcupine and fisher from the Law’s archaeological site ins northern Alabama which dates to about 1700 AD, and from the Etowah Indian Mound Site in Bartow County which dates to between 1100 and 1500 AD.  This doesn’t prove fishers lived in Georgia that recently.  Indians traded fisher pelts and porcupine quills, and they could have originated from their known historical range.  However, it’s quite possible fishers had a more southerly range within the last few hundred years and were trapped out by Indians selling pelts to newly available European fur markets. 

Historical range of the fisher.  They may have ranged further south but were uncommon and trapped out early after European contact.  During the Ice Age just about their entire modern range was under miles of glacial ice, so of course they once ranged further south in pre-historic times.

Ecological studies show fishers require continous tracts of mature forest, and they completely avoid open areas.  In New England now that fur trapping has gone out of style and forests are growing back, fishers are recolonizing states where they’ve been long absent.  They’ve got a long way to go before they reach Georgia though.

Fishers prey on squirrels, rabbits, mice, and birds.  Studies of their dietary habits have yet to find fish in their scat, so their name is misleading.  They’re one of the few carnivores that commonly prey upon porcupines, but they occasionally die from injuries suffered when they mishandle the spiny rodents.  They kill the porcupines by biting their faces off, not by flipping them over as is falsely believed.  Fishers will kill small house dogs and cats, but I don’t believe reports that they attack German Shepherds.  Fishers only weigh 10-15 pounds and would have a size advantage over smaller cats and dogs but a big dog could shake a fisher and break its back.  Scientists studying Canadian lynx report two cases of fishers feeding upon radio-collared cats.  I don’t believe a fisher can kill a full grown lynx.  In one instance there was no sign of a struggle in the snow which tells me the cat was already dead.  A fisher doesn’t have a powerful enough bite to kill a large animal instantly, precluding the possibility that it ambushed a sleeping cat.  I think the cat died of either sickness or starvation.  Likewise, a find of bobcat in fisher scat was probably from a kitten or an already deceased cat.  The following youtube video shows a fisher struggling to kill a gray fox.  Bobcats and lynx are much more powerful than gray foxes.  The former regularly preys on gray foxes.  (Note: The fox in the video is a gray fox, not a silver color phase of a red fox.)

http://www.youtube.com/watch?v=txdoUgli2FQ

When I visited the Silver Bluff Audubon Center a month ago, I heard a cry that sounded like the distress call of the gray fox from this video.  At the time I didn’t know what it was and thought I was hearing a bird I couldn’t identify.  Maybe I was hearing a gray fox being attacked by coyote or bobcat.

The Extinct Vero Tapir (Tapirus veroensis)

December 20, 2011

When I first began studying the scientific literature on Pleistocene mammals in 1988 I excitedly told my little sister and my now ex-brother-in-law that tapirs and capybaras used to live in Georgia.  Neither knew what a tapir or capybara was, and they looked at me like I was nuts.  This happened before the days of the popular internet, and I couldn’t readily show them photos of the animals on a computer screen.  Another great benefit of the internet is that I can communicate with people who actually care and also share my interest.

Mountain or woolly tapir (Tapirus pinchaque).  Of the 4 species of tapir in the world, this is the only one that inhabits a temperate forest.  The others are tropical.  The extinct Vero tapir also inhabited temperate forests as far north as what today is Kansas.  Like the Vero tapir, the mountain tapir is likely headed toward extinction.  There are only 9 in zoos and less than 2500 in the wild.

Jaw bone of a Vero tapir.  The partial jaw of a tapir is the only Pleistocene fossil reported from Anderson Spring Cave in Walker County, Georgia.  The ridged teeth are evidence they browse rather than graze.

View from inside Anderson Spring Cave, Walker County, Georgia.  The jaw bone of a tapir was found here.  Photo by Kelly Smallwood.

The type specimen of the Vero tapir was found in Vero Beach, Florida in 1915, and it was associated with human bones dating to about 14,000 BP–a find that caused considerable controversy at the time because mainstream archaeologists refused to believe humans lived in North America prior to 6,000 BP.  Apparently, the Vero tapir was a fairly common species in the Pleistocene southeast.  In Georgia fossils of the Vero tapir have been found at Ladds Mountain, Bartow County; Anderson Spring Cave, Walker County; the Isle of Hope site and Savannah River dredgings in Chatham County; and at Watkins Quarry in Glynn County.  Northern Alabama fossil sites produced tapir bones too.  Both Cave ACb-3 and Bell Cave were the final resting places for a few tapirs.  In the latter site tapir fossils were associated with caribou and long-nosed peccary bones–what an odd mix of ungulates.  This suggests the Vero tapir was a temperate species, capable of surviving subfreezing temperatures.  The still extant (though probably not for long) mountain tapir lives in cloud forests above 6500 feet in elevation in Peru, so it’s not all that unusual for a tapir species to live in a temperate climate, though the 3 other living species inhabit the tropics.

Extant tapirs are big strong animals weighing up to 600 pounds.  The Vero tapir was slightly larger than this, and it must have been a tough creature able to fend off big cats, wolves, and bears.  When cornered they bite and put up a ferocious battle, but more often they shake off their attackers by running through dense vegetation or diving into deep water.  Their tough hides keep them from getting scrapes and abrasions while stampeding through brush.  A recent television documentary on National Geographic Wild showed film of vampire bats feeding upon tapirs which ignored the pesky bloodsuckers.  Deer were much more sensitive and vigilant about keeping the bats from biting them, perhaps explaining why vampire bats are extinct in North America.  The bats need beasts with thick skins that can’t detect them.

The tapir’s unusual looking and prominent proboscis is utilitarian.  It’s prehensile and used to grip and strip branches of leaves.  They eat forest vegetation such as ferns, leaves, and succulent plants.  Their preferred habitat is moist woodlands and river bottomlands.  During the Pleistocene whenever climatic conditions favored the spread of woodlands tapir populations in southeastern North America probably expanded.  Unfavorable climatic conditions probably limited them to riverine corridors.  Modern tapirs are considered keystone species because they’re important seed dispersers.  Wax palms and highland lupines decline in abundance whenever mountain tapirs are hunted out of a region.  Certain plant species were likely more abundant during the Pleistocene,  thanks to the Vero tapir’s inefficient digestive system.  Some unknown species of plants may have even become extinct after tapirs were gone.

The terminal radiocarbon date for the Vero tapir in southeastern North America is 11,450.  This translates to a calender year date of 13,300 BP.  They probably lasted in isolated pockets for 2 or 3 thousand years longer, but they’ve been gone a long time now.  The mountain tapir has been discussed as a candidate for Pleistocene rewilding in North America.  This won’t happen.  The mountain tapir is expected to become extinct in the wild by the end of the decade.  It needs continuous stretches of cloud forest–patchy forests are inadequate.  All captive individuals are descendents of 2 individuals, so it will inbreed itself to death in zoos as well.  Last month, black rhinos were declared extinct in the wild. Our modern forests are already impoverished and devoid of diversity.  The loss of yet 2 more species of megafauna is unspeakably sad.