Posts Tagged ‘Kingston Saltpeter Cave’

The Squirrel-Conifer-Fungi Connection

June 14, 2014

The evolutionary divergence of the northern flying squirrel (Glaucomys sabrinus) from the southern flying squirrel (G. volans) is an excellent example of speciation resulting from environmental change.  Genetic studies suggest both of these American species of flying squirrels diverged from Eurasian flying squirrels between 4-6 million years ago.  Eurasian flying squirrels are much more diverse and include 44 species, most of which live in southeast Asia–evidence this part of the world is where they originally evolved.  During the late Miocene about 5 million years ago, a forested landbridge connected Asia with America, explaining how the ancestor of both American species of flying squirrels colonized this continent.  Genetic evidence suggests the 2 American species of flying squirrels diverged from each other early during the Pleistocene between 1-2 million years ago when Ice Ages began to become more severe.  Boreal spruce forests expanded during Ice Ages, growing as far south as middle Georgia and Alabama.  In the middle south spruce forests grew in higher elevations while deciduous oak forests still occurred in adjacent lower elevation.  Oak forests are rich in mast such as acorns and nuts, but spruce forests offer less food for squirrels–seeds from spruce cones are only available for 2 months of the year.  However, underground fungi, also known as truffles, are available year round in spruce forests.  For most species of squirrels, fungi is a minor component of their diet, but truffles and other fungi make up 85% of the northern flying squirrel’s diet whereas southern flying squirrels eat more acorns, nuts, berries, and animal matter.  The ancestors of the northern flying squirrel were those individuals from the parent population best able to subsist on a diet of mostly fungi.  These individuals were able to colonize spruce forests, while the rest of the parent population remained in oak forests.  Eventually, this habitat partition resulted in a divergence between the 2 American species.

Photo: Northern Flying Squirrel, Glaucomys sabrinus.

Northern flying squirrels eat mostly fungi which is a minor component in most squirrel’s diet.  The ability to subsist on a diet of mostly fungi enabled this species to colonize spruce forests.  Eventually, they evolved into a different species than southern flying squirrels because of this capability.

Elaphomyces or truffle–favorite food of the northern flying squirrel.

 

 Red Spruce (Picea rubens)

Red spruce (Picea rubens).  Red spruce, truffles, and northern flying squirrels are beneficial and interdependent to each other.

Fossils of both species of flying squirrels have been found at Ladds and Kingston Saltpeter Cave in Bartow County, Georgia.  This is evidence that patches of spruce forest grew near patches of oak forest in this region during some climatic stages of the Pleistocene.  Northern flying squirrels are confined to the former; southern flying squirrels require the latter.

There is an interesting ecological interdependence between northern flying squirrels, red spruce, and several species of fungi.  Truffles grow intertwined with the red spruce roots, and they exchange nutrients.  The squirrels eat the truffles and spread their spores throughout the forest in their droppings.  A healthy spruce forest requires an abudance of truffles.  Many red spruce forests have been logged, and without the squirrel’s help, trees such as oak, maple, beech, and cherry are replacing them.  In West Virginia the U.S. Forest Service has successfully re-established red spruce forests.  Foresters discovered that red spruce seedling grow best in ground ripped apart by bulldozers and strewn with woody debris.  Some of these young spruce forests are on land reclaimed from strip mining. 

 Report fox squirrel sightings in Florida Sherman's Fox Squirrel

Fox squirrel.  This species may play a role in distributing fungi in longleaf pine savannah. 

Rhizopogon nigrescens–a fungi common to longleaf pine savannahs and likely an item in the diet of the fox squirrel.

Virgin stand of longleaf pine (Pinus palustris) in east Texas (circa 1908).

Although fox squirrels (Scirius niger) have a much more varied diet than northern flying squirrels, they occasionally eat fungi and may play a role in the health of longleaf pine savannahs.  Certain kinds of fungi that grow in the soil of savannahs also exchange nutrients with longleaf pine trees, and fox squirrels spread these spores in their dung as well.  Fox squirrels and longleaf pine savannahs were formerly common in the south, particularly on the coastal plain, but today both are rare.  The changes man has wrought have really sickened the natural communites of the world.

Reference:

Arbogast, Brian

“A Brief History of the New World Flying Squirrel: Phylogeny, Biogeography, and Conservation Genetics”

Journal of Mammalogy 88 (4) 2008

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Inland Shorebirds of the Pleistocene

April 19, 2013

The Scolopacidae family includes birds that are commonly considered denizens of the sea shore, such as sandpipers and curlews, but 3 species are primarily terrestrial inhabitants.  The upland sandpiper (Bartramia longicauda), also known as the golden plover or Bartram’s plover, is the one most easily recognizable as a relative of its familiar sea shore cousins.   However, it preferes grassy environments where it feeds upon insects and grass seeds instead of marine worms, clams, and fiddler crabs.  Upland sandpipers were formerly an abundant bird of the prairies on the Great Plains and in the midwest, but market hunting destroyed the primeval population, and farmers replaced prairie grasses with fields of wheat and corn that are unsuitable habitats for this bird.  In March 1821 just 1 market hunter killed 48,000 upland sandpipers, demonstrating how abundant they used to be.  (They were regarded as a delicacy by Creole cooks.)  This bird will never regain its former abundance, but the remaining population is adapting to new anthropogenic grasslands–abandoned strip mines and airports.  

Upland sandpiper.  They are a ground nesting bird that feigns injury to draw predators away from their eggs and nestlings.

The upland sandpiper is a summer migrant to North America, and it winters on the Pampas of South America.  Aside from an occasional vagrant, this bird is presently absent from the southeast, but it was a common species in this region during the Pleistocene.  Fossil evidence of upland sandpipers, dating to the late Pleistocene, were found in Kingston Saltpeter Cave, Bartow County, Georgia and in Bell Cave in Northern Alabama.  This geographical area was mostly forested then, but extensive grasslands must have also existed because upland sandpipers favor nearly treeless habitats.

Both the above mentioned fossil sites yielded remains of the woodcock (Scolopax minor) as well, another terrestrial member of the Scolopacidae.  This bird uses its unusually long bill to probe moist earth for worms and grubs.  They are year round residents in the south, but much of the population migrates north for the summer.

Woodcock.  In Ohio they are arriving a month earlier in spring than they did 100 years ago due to global warming.

Woodcocks spend their days hiding in the woods but feed in open areas at night.  They favor 2nd growth woods with thickets that are adjacent to agricultural fields where they can hunt for earthworms in the tilled soil.  Like upland sandpipers, woodcocks are much less common than they used to be because of hunting and habitat loss.  In the Pleistocene south woodcocks likely were abundant because megafauna foraging and sudden climate fluctuations created mixed environments of young and old forests, thickets, and grasslands.  Moreover, large predators such as wolves and big cats kept numbers of foxes, raccoons, and possums relatively low, reducing nest predation.  The south was a refuge for woodcocks during the height of the Ice Age.  Genetic studies suggest the woodcock population expanded rapidly following the retreat of the glaciers as more habitat became available.

Male woodcocks display by making a “peent” call before flying in wide spirals above their potential mates.  The females lay eggs on the ground and carry their young with them for 18 days until the nestling learns to fly.  Then in late summer when they moult, woodcocks can’t fly and must hide in thickets, thus explaining why they need varied habitats.

Wilson’s snipe (Gallinago delicata) is another species of terrestrial Scolopacidae.  They live and nest in marshes where they hunt for worms, grubs, insects, and some plant matter.  They are an erratic fast flyer, making them difficult to shoot, hence the origin of the word, sniper.  Wilson’s snipes have a curious pattern of migration.  They winter in the southeast as well as in South America and migrate over dry land in the late winter and early spring.  But when they migrate south, they travel over the coast.  This explains why there are an additional 9 species of snipe endemic to various islands.  Storms blew some flocks off course where they found permanent refuge on isolated oceanic islands.

Wilson’s snipe–a marsh bird.  Their habit of migrating south over the coast has resulted in speciation on isolated islands.

Even some coastal species of Scolopacidae occasionally find their way far inland.  Joel McNeal photographed stilt-legged sandpipers, lesser yellowlegs, black necked stilts, pectoral sandpipers, long-billed dowitchers, American avocets, western sandpipers, and semi-palmated sandpipers foraging on the sod farm that surrounds the Etowah Indian Mounds in Bartow County.  Here’s a link to his photos. http://www.pbase.com/joelmcneal/bartowbirds

The Nature of the Picayune Creole Cookbook

November 21, 2012

In honor of Thanksgiving, the American holiday dedicated to gluttony, I offer this food-oriented essay.

Editors and journalists from the New Orleans Picayune newspaper published the Picayune Creole Cookbook in 1901 from recipes compiled in the late 19th century.  If the reader is interested in this cookbook, be sure to purchase the facsimile of the original published by Dover Publications and not the newer version published by Random House in 1987.  The ignorant clods who updated the original left out most of the historical recipes that made the original so unique and valuable for food historians.   The text of the original version is available for free online from the following link http://archive.org/stream/cu31924073878708/cu31924073878708_djvu.txt

The great variety of organisms consumed by Creoles during the 19th century makes the Picayune Creole Cookbook  an interesting one for naturalists as well as food historians.  Today, turtles are a regional specialty but have gone out of culinary style for most of the United States.  For 19th century Americans, turtle meat was an abundant and common source of protein.  The Picayune Creole Cookbook gives recipes for green sea turtles and diamondback terrapins.

Diamondback terrapin.  Reportedly a delicacy.

Diamondback terrapins live in saltmarshes all along the Atlantic coast from New England to Mexico.  Like so many other animals, they were formerly abundant but today are rare due to human consumption and coastal development.  I’ve never seen one.  Turtles were cooked in soups and stews, giving me the impression the meat is tough.  Turtle meat is not sold in stores around Augusta, Georgia and I’ve never eaten turtle.

The sheepshead was the most popular and “versatile” fish used in New Orleans around the turn of the century.  This species uses its human-like teeth to crush the shellfish that it feeds upon.  This diet is probably what makes them taste so good.

The teeth on a sheepshead look very human-like.  They eat clams and the teeth crush the shells.

Look at that beautiful…fish!

The Picayune Creole cookbook also has 5 recipes for eel, 4 for stingray, and 6 for frog.  Oddly enough, the only recipe for a freshwater fish species is for roe from green trout which is the name they used then for largemouth bass.  Most of the fish recipes are for marine species including pompano, bluefish, flounder, red snapper, red drum, and croaker.

One of the most interesting dishes in the book is Pigeon a la cardinale, known also as pigeon and crawfish–a combination I bet not a single person in the world will eat for supper tonight.  The dish calls for baking 3 pigeons between layers of bacon in a pan filled with beef broth and onions.  The crawfish are boiled separately.  After the pigeons and crawfish are done cooking, a little of the crawfish boil water is added to the beef broth and the pigeons are garnished with the crawfish.  The authors of the cookbook differentiate between domestic and wild pigeons.  The availability of passenger pigeons at the market was still a recent memory when they were compiling the recipes for this book.

The Picayune Creole Cookbook states that the pigeon and crawfish dish is “Creole to the letter.”  Now this dish is almost unheard of.  The above photo is the closest match I could find on google images.  It’s a roasted pigeon served with crawfish tails, softshelled crab, and vegetables, but not with bacon and a gravy made from pigeon, beef, and crawfish broth.  Passenger pigeons and crawfish were at one time both abundant, making pigeons and crawfish a practical dish.  Now, it’s not at all economical to make.

The canvasback duck (Nyoca vallosneria) was praised as the best-eating waterfowl because it ate wild celery (Vallosneria spiralis).  Some ducks eat a lot of fish, but canvasbacks are mostly vegetarian.  This diet gives their a flesh a savory quality.  They were simply seasoned with salt, pepper, and lemon juice and broiled quickly.

Male and female canvasback ducks–reportedly the best tasting of all ducks.  Duck is one of my favorite foods.

The bobolink (Dolichonyx oryzivorous) known as the reedbird in the Picayune Creole Cookbook, apparently was common table fair when in season. The second part of its scientific name means rice-devourer.  It still is a pest for rice farmers.  Creoles shot these members of the blackbird family to protect their rice fields.  It only takes 5 minutes to broil small birds such as bobolinks (robins and larks were also prepared this way).  I’ve never eaten a bird smaller than a quail.  It takes at least 2 quail to equal the amount of meat from about 1/4th of a chicken.  It probably takes about 4 bobolinks to equal 1/4th of a chicken.

The bobolink, also known as the rice bird.  It’s a pest to rice farmers and table fair for Creoles.

It took me a while to figure out what a pababotte was.  I’ve determined that the pababotte discussed in the Picayune Creole Cookbook is probably the upland sandpiper (Bartramia longicauda).  The upland sandpiper is a denizen of the prairie.  Fossil specimens of this species were discovered at Kingston Saltpeter Cave in Georgia and Bell Cave in Alabama.  Both localities are in a region where upland sandpipers are absent today aside from an occasional vagrant.  This is evidence that small pockets of prairie existed within the mostly forested region of the upper south during the late Pleistocene.  Upland sandpipers were once an abundant bird but overhunting and agriculture have greatly reduced their numbers.  J.J. Audubon witnessed 48,000 upland sandpipers killed in a single day by a group of hunters in 1810.  Creoles serve them stuffed and braised, roasted, or broiled.

Upland sandpipers were more widespread during the Ice Age.

Until 1861 an old French woman produced Fois Gras in New Orleans.  She raised geese in small cages.  She kept their feet nailed to the cage floor and force fed them to enlarge their livers.  I’m sure the enlarged livers are rich and delicious, but the practice seems cruel and wasteful–the rest of the meat is flabby and unfit for eating.  Raising geese for Fois Gras is illegal in the U.S. today.

There are many recipes in the Picayune Creole Cookbook that don’t require extinct or rare animals to make.  One of the best I’ve tried is a soup made out of beef ribs, corn, and tomatoes.  I could live on lentil salad–a simple recipe of lentils tossed in a vinegarette.  The gumbo recipes from the book use less roux than most modern gumbos and instead are thickened with powdered sassafras leaves or okra.  A gumbo made out of a leftover turkey carcass is an excellent example of frugality but I prefere a more roux-heavy version.  There are 7 recipes for different types of sausages, and I’ve made several, though in the shape of hamburger patties rather than links stuffed in casings.  For the home cook I think this book is still useful and will never go out of date.

Pleistocene Turkeys (Meleagris sp.)

November 16, 2012

Early European colonists reported seeing flocks of wild turkeys numbering in the hundreds.  Turkeys flock together in the fall when they concentrate in areas abundant with such favored foods as acorns and grapes.  The hens and their young stay in separate flocks from the adult toms because the latter will peck the juvenile toms to death on sight.  In late winter and early spring the adult toms battle each other for the right to mate with the hens, and these battles also can sometimes cause fatalities.  The champion turkeys get to mate with several hens.  By mid-spring the hens leave the toms and lay as many as 20 eggs in cleverly concealed spots that they cover with leaves.  J.J. Audubon wrote the hens “…separate themselves, in order to save the eggs from the male, who would break them all, for the purpose of protacting his sexual enjoyments.”  The hatchlings follow the mother around and grow quickly on a diet of insects, arthropods, small vertebrates, grass, and fruit; so that by mid-summer they’re capable of escaping predators more often than not.

Two tom turkeys (Meleagris gallopavo).  Turkeys were common across most of North America during the Pleistocene.  There also were two now extinct species of turkey restricted to the southwest and California.

The oscellated turkey (Meleagris gallopavo), the only other extant species of turkey besides the eastern turkeys pictured above.  It resembles a peacock.  Turkeys evolved from an ancient species of peacock that crossed the Bering landbridge 30 million years ago.

Today, there are only 2 species of turkeys–the eastern turkey (Meleagris gallopavo) which lives over a wide swath of varied habitats in North America, and the oscellated turkey (Meleagris oscellata) which is restricted to the Yucatan penninsula in Mexico.  During the Pleistocene there were 2 additional species of turkeys though they were much more localized in distribution than the eastern turkey.  The southwestern turkey (Meleagris crassipes) lived in Arizona and New Mexico.  The California turkey (Meleagris californicus) lived in southern California.  The California turkey left more fossils at the La Brea tar pits than any other species of bird other than the golden eagle.  Scientists believe the turkeys scratched the surface away from the top of tar seeps, and the weight of the birds caused them to become mired in the tar.  Turkeys can weigh up to 50 pounds.   As of 2006, 11,116 specimens from at least 791 individual turkeys had been found in the tar pits.  Golden eagles attacking prey stuck in the tar pits became entrapped in turn, explaining the abundance of golden eagle specimens here.  Turkeys were probably a common item in the diet of the eagles. 

Range map of the eastern turkey colored purple.  The yellow is the estimated range of the Pleistocene California turkey.  Eastern turkeys have been introduced to California and other areas of the arid west where in some areas they depend upon manmade water sources for survival.

Anatomical evidence suggests California turkeys evolved from eastern turkeys, probably after the 2 ancestral populations became geographically separated when the territory between them became desert.  Turkeys require trees for roosting and a daily water supply, so desert habitats are unsuitable for them.

The extinction of the California turkey and the southwestern turkey can be blamed on a combination of environmental and anthropogenic factors.  The extinctions coincide with a dry phase of climate that lasted for hundreds of years and began about 11,500 BP.  However, scientists noted the 2 species survived an even drier period that occurred ~38,000 BP.  The scientists authoring the below referenced study suggest California turkeys flocked around shrinking sources of water where they were completely rubbed out by paleoindians.  If not for man, these 2 extinct species of turkeys would likely still be extant.  Trees and bodies of water have always been abundant in eastern North America, explaining why eastern turkeys survived man’s onslaught, until Europeans raped the environment and almost drove them into extinction too before modern conservation practices saved them.

David Steadman, one of the world’s foremost experts on Cenozoic bird evolution, thinks turkeys share a common ancestry with the peacock based on anatomical similarities.  He believes a peacock-like fowl crossed the Bering landbridge ~30 million years ago, and all subsequent turkey species were descendent from this species.  A fossil species, Rhegimornis calbates, dating to the early Miocene, had anatomical characteristics intermediate between the turkey and the peacock.  Remains of Rhegimornis were found in Florida.  The modern turkey probably evolved by late in the Pliocene–~2.5 million years BP.   Fossils of Pleistocene-aged turkeys have been found in Georgia from Ladds and Kingston Saltpeter Cave.

Turkeys evolved from a peacock-like ancestor that crossed the Bering landbridge ~30 million years ago.

Reference:

Bochenski, Zbigniew; and Ken Campbell

“The extinct California turkey, Meleagris californicus, from Rancho La Brea: Comparative Osteology and Systematics”

Natural History Museum of California Publications 2006

Crappie and mastodon

December 12, 2011

Crappies and mastodons shared the same habitat.  Crappies are primarily a lake fish, preferring clear still water where they prey on small minnows and insects.  Mastodons often waded into lakes to feed upon submerged aquatic plants.  Perhaps they even aided crappies by forcing minnows away from the cover of underwater vegetation into the open to be picked off by schools of crappie.  Of course, mastodons weren’t as tied to the water as crappies and could travel overland whenever they desired.

Black crappie (Pomoxis nigromaculatus).  A beautiful fish and tasty too.  I once had a fish dinner of bass and crappie.  The bass were meatier, but the crappie were sweeter and better tasting.

Kurt Hamlin, a curator at the Milwaukee Museum, was lucky enough to find fur on a mastodon specimen.  The fur resembled that found on river otters and beavers, so we know mastodons spent a lot of time in the water.

River otter (Lutra canadensis) pelt.  River otter fur is water proof and dries quickly.  Mastodon fur was similar.

Although these two different species shared the same habitat, the fossil remains of mastodon and crappie have been found together at only 1 locality–The Charles Adams Mastodon Site in Livingston County, Michigan.  It was a lake deposit also containing fossils of meadow vole, 1300 snail shells, 500 freshwater clam shells, and bones of white sucker fish.  In Georgia mastodon fossils have also been found associated with fish remains, but not crappie.  An alluvial deposit in Little Kettle Creek contained bones of channel catfish along with mastodon.  The  deposit in Kingston Saltpeter Cave in Bartow County contained over 500 fish bones in addition to a mastodon fossil. Here, predatory birds brought  fish from the nearby Ashpole Creek, a tributary of the Etowah River.  They included gar, pickerel, channel catfish, bullheads, sucker fish, chubsuckers, largemouth bass, and unidentified sunfish.  Coastal fossil sites often have marine species of fish as well as mastodon.

Overall, fish populations during the Pleistocene were much higher than those of today’s waters.  Then the rivers were undammed, unpolluted, and unfished by men.  But in what’s now Georgia crappie populations were probably an exception.  They thrive in modern artificial reservoirs formed behind the numerous hydroelectric dams.  Suitable habitat during the Pleistocene was temporary and sporadic.  Oxbow lakes were plentiful during interstaidals and interglacials.  Cut off channels were common during stadials.  But large lakes akin to modern day reservoirs were nonexistent.  Instead, crappies relied on favorable habitats that constantly changed with the evershifting river patterns.  They can live in rivers where water flow is obstructed and forms pools.  Lower water levels with still channels, and higher water levels with wide bends that form slow moving water both provide favorable habitat.  Crappies could also inhabit large beaver ponds.  But the constantly changing conditions probably made crappie numbers fluctuate much more than they do in today’s reservoirs.

Centrarchid Evolution

An evolutionary tree of the centrarchid family of fishes as proposed by some scientists.

 The centrarchid family of fish includes sunfish, crappie, and bass (though not white bass, striped bass, and sea bass which are in completely different families).  The opportunity for speciation occurs often among this family because populations of fish get isolated when connecting streams run dry or become obstructed.  This makes the centrarchid family an excellent one for evolutionary scientists to study.  Scientists can look at rates of genetic divergence between closely related species and estimate the length of time it has taken since speciation occurred from a mutually ancestral species.  They call this a speciation clock. Many species of centrarchids hybridize but genetic compatibility decreases with time since speciation occurred.  One study found that hybrid embryo viablity declines 3% per million years of separation.

Here’s a list of centrarchid species which are strictly an American family of fish.  Note:  Some scientists recognize 33 species and 7 genera; others recognize 31 species and 9 genera.

Mud sunfish–Acantharchus pomotis

Shadow bass–Amploplites aribmarus

Roanoke bass–A. cavifrons

Ozark Bass–A. constellatus

Rock Bass–A.  rupestris

Sacramento perch–A. choplites

Blackbanded sunfish–Ennearanthus gloriousus

Flier–Centrarchus macropterus

Redbreast Sunfish–Lepomis auridus

Green sunfish–L. cyanellos

Pumpkinseed sunfish–L. gibbosus

Orange spotted sunfish–L. humili

Warmouth–L. gulobus

Bluegill–L. marochirus

Dollar sunfish–L. marginatus

Longear sunfish–L. megalatis

Redear sunfish–L. microlophus

Red spotted sunfish–L. miniatus

Spotted sunfish–L. punctatus

Bantam sunfish–L. symmetricus

Redeye or Coosa Bass–Micropterus coosae

Spotted Bass–Micropterus punctatus

Largemouth Bass–Micropterus salmonoides

Shoal Bass–M. cataractus

Guadalupe bass–M. treculi

White crappie–Pomoxis annularis

Black crappie–P. nigromaculutus

Redeye bass

A redeye bass.

In my blog entry of a few weeks ago about the food I would eat, if I could live in Georgia 36,000 BP, I mentioned smallmouth bass as a fish I might find in my fish traps on the Broad River.  At the time of European colonization of North America smallmouth (aka spotted) bass only occurred in extreme northern Georgia.  It did not naturally occur in the Broad River, though it has since been introduced.  During the Pleistocene, smallmouth bass may have ranged further south, but maybe not.  Instead, redeye bass, a closely related species, did occur on the Broad River.  Redeye bass and smallmouth bass probably evolved from a common ancestor that diverged due to the geographical separation of the watersheds where this common ancestor lived.  So, I believe I would find redeye bass in my Pleistocene fish traps in the Broad River, and probably not smallmouth.

Reference:

Bolnick, Daniel; and Thomas Neal

“Tempo of Hybrid Inviability in Centrachid Fish (Telestei: Centrarchae)”

Evolution 59 (8) Augusts 2005

The Vanishing Chinkapin (Castania pumila)

April 20, 2011

Photo from google images of chinkapin nuts in a burr.

The chinkapin, a shrubby relative of the American chestnut and not to be confused with the similarly named chinkapin oak (Quercus muhlenberger), used to be locally common, growing on the tops of rocky hills in the piedmont region of the southeast and in the undergrowth of open pine savannahs on the coastal plain.  The early explorer, John Lawson, reported the trees as so common that hogs fattened on the nuts.  He described the nuts as smaller, rounder, and sweeter than those of its relative, the chestnut.  Most sources state that it was the better tasting of the two.  William Bartram found chinkapin growing in association with chestnuts and chestnut oaks (Quercus prinus) on the tops of rocky piedmont hills, a forest type that contrasted with that of the surrounding area which was mostly an oak forest but in the valleys between the rocky hills a much richer forest of black walnut, beech, hackberry, tulip, and sycamore grew.  Moist creek bottoms and richer soils kept the latter area from burning, but the thin dry soils at the tops of rocky hills endured frequent fires.  Oak and chinkapin thrive in fire prone sites because they’re shade intolerant and need open areas to grow.

Most of the jobs I’ve had in the Augusta, Georgia area have taken me to just about every neighborhood in Richmond and Columbia Counties.  I used to survey lawns for Orkin Lawn Care, and I worked for many years as a route manager for the Augusta Chronicle. While working I, of course, took note of the vegetation (ecology has always held a great interest for me), and I’ve never seen a chinkapin.  Botanists warn the chinkapin is in decline for a number of reasons: fire suppression, chestnut blight, and suburban development.  Without fire, shade tolerant trees begin to dominate, and chinkapin can’t grow in the shade.  The chestnut blight completely destroyed the once common chestnut forests.  The chinkapin is also susceptible but is better able to survive because it is a shrub that resprouts and can produce a crop of nuts before it dies back again from the disease.  Still, the blight reduces overall nut production.

The chestnut blight was a disaster for the ecosystem.  Chestnuts and chinkapins were important sources of food for wildlife.  Now, trees such as tulip, which produce no mast, have replaced chestnuts.  They may be beautiful trees but animals can’t eat beauty.  I think the lack of chestnuts explains why I saw almost no wildlife on my trip to the Smoky Mountains National Park last summer (see my blog entry “Gatlinburg, Tennessee: Tale of a Tourist Trap Nightmare” which is I believe in the June 2010 archives).

The chinkapin has two interesting adaptations that help it survive as a species.  It germinates quickly in the fall.  The nut ripens from September to November, and they produce heavily–up to 1500 nuts per bush, beginning when they’re just six years old.  Squirrels disperse the species by burying the highly valued food, but the chinkapins foil the squirrels when they germinate immediately.  After they’ve become a seedling, the squirrel can’t utilize them.  Fall germination prevents animals from destroying the entire progeny, but by producing a nut with high food value, they motivate the squirrels to disperse them.  The other adaptive characteristic is its ability to resprout vigorously.  Fire may kill the main trunk, but chinkapin will resprout and form thickets.  Deer also find chinkapin a favored food and will browse down the main trunk, causing the shrub to resprout and create thickets.  Their thickets provide great cover and food for turkey and grouse.

Fossil evidence shows that turkey and grouse were quite common in upland Georgia during the Pleistocene–both left abundant specimens at Ladds and Kingston Saltpeter Cave in Bartow County.  Two studies of sediment cores in Georgia found that chestnut/chinkapin made up about 2%  of the pollen spectrum during the Pleistocene.  Both sites (Nodoroc and Grays Reef) date to about 30,000 BP.  Chinkapin surely was a common component of the open oak and pine savannahs so prevalent then.  Its ability to resprout and fall germinate is an ancient adaptation to survive fire and megafauna foraging.  The more such animals as mastodon, horse, llama, and deer browsed, the more this shrub would bounce back and form thickets ideal for bird life.

The Indians used to cook chinkapin and hickory nuts with their venison in well-rounded stews.  Chinkapins are a nice starchy substitute for bread or potatoes; hickory nuts provided a nice oily substitute for butter.  Chestnuts, unlike most other nuts, are primarily a carbohydrate based food, rather than a fatty form of sustenance.  They’re sweet and bready and act as a laxative.  I hate to buy expensive imported European chestnuts when I think how abundant and cheap American chestnuts and chinkapins used to be.

Pleistocene Bears of Southeastern North America

March 10, 2011

Nothing demonstrates wilderness more than a robust population of free roaming bears.  During the Pleistocene before people were around to kill them and destroy their habitat, there must have been tens of thousands of bears living within the boundaries of what today is Georgia.  It’s possible that 5 different species could have been found here in the same time span, though we can be more sure there were at least 3 sharing the same range.  Today, only 1 species of bear resides in Georgia–an estimated 5100 black bears still roam the mountains, the Okefenokee Swamp, the Altamaha and Ocmulgee river bottoms, and Houston County.  Occasional stragglers leave these last strongholds and raid urban dumpsters and suburban bird feeders, but these occurrences are rare.  One study of Georgia bears determined that suitable habitat can support 1 bear for every 3 square kilometers.  That means ideally, Pleistocene Georgia hosted a population of 30,000-40,000 bears.  (*Georgia is about 60,000 square miles. 1.86 square miles =3 square kilimeters.  Moreover, during stadials Georgia’s land mass increased by about 10,000 square miles due to the fall in sea level.)

Here’s a review of every known bear species that lived during the Pleistocene in southeastern North America.

Black bear–Ursus americanus

Photo from google images of a black bear in the Okefenokee Swamp.

Ursus abstruscus is the probable evolutionary ancestor of American and Asian black bears which once consisted of a geographically continuous population.  Glacial ice separated the two populations at the beginning of the Pleistocene, resulting in two different species.  Bjorn Kurten notes that Pleistocene black bears grew as large as modern day grizzlies.  I believe Pleistocene black bears were larger and fiercer than their modern day descendents because they had to survive confrontations with saber-tooths, giant panthers, jaguars, and packs of dire wolves.  Cavers and scientists discovered black bear fossils at Ladds and Kingston Saltpeter Cave in Bartow County, and the Isle of Hope Site in Chatham County.  They’re also commonly found in Florida fossil sites but only a few have been recorded from South Carolina.

Florida spectacled bear–Tremarctos floridanus

Photo of a spectacled bear, Tremarctos ornatus,  from google images.  This is the only living species from the once widespread short-faced bear family.  It is a close relative of the extinct Tremarctos floridanus.  Of course, scientists have no way of knowing whether Tremarctos floridanus was also spectacled, but they call it that anyway.

Now extinct, this was likely the second most common species of bear in southeastern North America during the Pleistocene.  Only 1 specimen has ever been recovered in Georgia (at Ladds), but its fossils have commonly been found in Florida and South Carolina.  It’s thought of as primarily a vegetarian, but a recent study of Pleistocene bears concluded that all were opportunistic omnivores that would eat anything they could obtain.  Tremarctos’s range in the late Wisconsinian Ice Age seems to have been restricted to the southeast.  During warm interglacials it expanded as far north as Kentucky.  It probably just lived in the coastal plain of Georgia and South Carolina as well as Florida during colder climatic stages.

Lesser short-faced bear–Arctodus pristinus

Photo of a fossil jaw bone of Arctodus pristinus from Additions to the Pleistocene Mammal Fossils of South Carolina, North Carolina, and Georgia by Albert Sanders.

Photo of fossil bear teeth from the above mentioned publication.

It’s unclear from the fossil record whether this species co-existed with its larger cousin, the giant short-faced bear, or was simply ancestral to it.  Its fossils have only been recovered from a few eastern sites in Florida, South Carolina, Maryland, and West Virginia.  Teeth attributed to this species overlap in size with those of Arctodus simus.  Florida fossils of this species, including those from Leisey Shell Pit, indicate this animal lived from the early to mid-Pleistocene (~1.8 million-300,000 BP), whereas giant short-faced bear fossils in Florida date to the late Pleistocene (~300,000-~11,000 BP).  However, fossils of the lesser short-faced bear were found in South Carolina sediments thought to date from the Sangamonian Interglacial (~132,000-~118,000 BP) which is also considered late Pleistocene.  These South Carolina specimens haven’t been radiometrically dated, so no one knows exactly how old they are.  Perhaps this species did survive as a relic species in some geographical locations until the megafauna extinction.  Arctodus pristinus is considered more of a general feeder; Tremarctos floridanus a more herbivorous species; Arctodus simus a more carnivorous bear.

Giant short-faced bear–Arctodus simus

Dan Reed’s photo-shopped reconstruction of a giant short-faced bear.   

The giant short-faced bear ranks up there with mammoths, mastodons, ground sloths, and saber-tooths as among one of the most spectacular creatures of this era.  Studies suggest it lived by aggressive scavenging.  It’s extremely acute sense of smell detected blood from a great distance.  Then, the beast would relentlessly trot toward the source of the appetizing odor, and its sheer size would intimidate the partially satiated carnivore that actually made the kill into surrendering the carcass.  Arctodus simus fossils are more common in western fossil sites, but a few have been discovered in the southeast, proving it did occur here, at least sporadically.  An Arctodus simus skeleton rested in the Fern Cave system in Jackson County, Alabama which borders northwestern Georgia, until it was discovered by cavers in 1970.  In addition a number of teeth from this species have recently been discovered in north Florida fossil sites, and some Arctodus simus material was also discovered in Virginia.

Grizzly bear–Ursus arctos

Photo of a grizzly bear and cub from google images.

Welsh cave in Kentucky yields grizzly bear fossils dating to about 12,000 BP.  This is the easternmost known occurrence of this species.  Grizzly bears roam hundreds of miles, so it’s likely if they lived in Kentucky then that they must have entered Tennessee.  But the lack of grizzly bear fossils in other southeastern states suggests they never penentrated the region in significant numbers.  Still, I believe a few irregular stragglers may have wandered into what’s now north Georgia.  It may be that the existence of 3 or 4 other species of bears prevented grizzly bears from colonizing much of the southeast during the Pleistocene, and then man arrived, creating another obstacle blocking their migration into the region.  Grizzly bears are a relatively recent addition to North America’s mammalian fauna, but they did live on the continent prior to the LGM, 30,000 years BP.  They’re the same species as the Eurasian and Alaskan brown bears.

If I could live in the Pleistocene (part 4).

For those unfamiliar with this blog, I occasionally fantasize living during the Pleistocene but with modern conveniences, such as an adobe house with woodstoves, solar heating, electricity, and a time tunnel that connects me to the modern world.

I’ve thought of a simple way to observe bears from my abode.  Connected to my Pleistocene house is a 5 story watchtower designed in the shape of a lighthouse in which I can view the surrounding landscape.  I would take a barbecue grill to the fifth story which has a canopy but an open window stretching for 360 degrees around.  There, I would grill meats.  The aroma should attract bears and other carnivores from miles around.  A bear could potentially climb up the side of a light-housed shaped building, so I would have to have some kind of designed guards that would prevent this. 

I would avoid hunting bears, if possible.  I think modern hunters who kill bears are jerks.  I can understand why the pioneers did it.  They didn’t have grocery stores and had to eat and make use of what they could obtain.  But there is no reason to hunt bears today, unless they prove a danger to tourists.  They don’t reproduce as rapidly as deer, and it’s just not ecologically necessary to hunt them.

Bears were a valuable source of meat and fat for early settlers.  Early accounts reveal an important dish of the Indians.  The Indians frequently diced up venison (which is very lean) and fried it in bear fat.  Bear fat was also the number one source of cooking fat in New Orleans in 1800.  It was gradually replaced by lard as the settlers brought in hogs.

 

What was the Deer-Hunting like in Pleistocene Georgia?

September 3, 2010

Deer-hunting season begins in Georgia this month.  The only native species of deer modern hunters can hunt in state is the white tail deer (Odocoileus virginianus) which numbers close to 1.2 million, making it the second most common large mammal in the state, behind man.  This season, hunters are allowed to take an astonishing 10 antlerless and 2 antlered deer, suggesting either a shortage of hunters or an overpopulation of deer.

The fossil record provides evidence that white tail deer were a common large mammal species during the Pleistocene too.  Their bones are found in almost all Pleistocene-dated sites in state.  They’re a species that prefers forest edge habitats, and the dynamic ecosystems of the Ice Age with fire, rapid climate fluctuations, and megafauna  destruction of trees, created extensive areas of this type of habitat.

Photos I took of white tail deer at Fripp Island, South Carolina.  The deer here are numerous and have little fear of humans.  Nevertheless, they should not be approached or fed because they are unpredictable wild animals and dangerous.  They can use their hooves to stomp people.  Deer have been known to kill dogs.

I suspect elk (Cervus canadensis) may have been the second most common kind of deer in what’s now Georgia during the Ice Age, ranging as far south as the fall line between the piedmont and the coastal plain.  Elk fossils from Kingston Saltpeter Cave in north Georgia, and near Charleston, South Carolina are the southernmost record of this species.  None have been found in Florida’s abundant fossiliferous deposits.  I think this is evidence of an abrupt difference in climate between the piedmont region of southeastern North America and the coastal plain.

Scientists don’t know much about the extinct fugitive or stilt-legged deer (Sangamona fugitiva).  It was like a white tail deer but approached an elk is size, maybe being slightly smaller.  The deer lived in east central North America from Missouri to West Virginia and a definitive record comes from Hamblen, Tennessee.  It probably occurred in northern Georgia because Dr. Clayton Ray found a tooth that may or may not have been from this species–the specimen was in too dodgy a condition to identify with certainty.

That caribou (Rangifer caribou) lived in northern parts of southeastern states during the Ice Age fascinates me.  Caribou fossils discovered in Bell Cave, Yarbrough Cave in Georgia, and near Charleston, South Carolina are evidence this species lived much further south than it did in historical times.  Were they stragglers or members of large migrating herds that regularly travelled through Georgia?  I wish I knew.

The stag-moose, or elk moose (Cervalces scotti) is kind of misnamed for it wasn’t closely related to a moose or an elk.  It was named so because it slightly surpassed a moose in size and sported antlers similar to those of the elk.  However, it was a distinct species, now extinct.  Its fossils are occasionally found in places like Ohio or New York.  One tooth of this species was discovered in Magnolia Phosphate Mine near Charleston (as I noted in a previous blog entry about the site)–evidence a small population roamed the upper south.

Pleistocene venison may have had a bitter flavor.  According to pollen records, wormwood (Artemesia) flourished more abundantly in the south than it does today.  This plant still commonly occurs in western localities, such as in Yellowstone National Park.  Reportedly, game that’s been eating wormwood acquires a bitter taste.  I can attest to the fine qualities of wild Georgia white tail deer meat–it tastes like dry beef, and I think the wild venison is better than New Zealand farm-raised animals, which though also good, tastes more like lamb.

Pleistocene Passenger Pigeon Populations

August 27, 2010

(Please forgive the excessive alliteration in the title.)

It’s hard to imagine the massive number of passenger pigeons (Ectopistes migratorius) that used to live in North America as recently as the mid to late 19th century.  For a description of their numbers, I’ve dug up an account J.J. Audubon gave in his Ornithological Biography.  Before I reprint this passage I want to comment on his writing style.  I enjoy his prose, but he does have a bad habit of writing in the passive voice, a style Stephen King in his book, On Writing, referred to as farting in an elevator.  Also, English was his second language because he was born in France.  Nevertheless, I think this makes for a fascinating description of a nature scene that no longer exists.

The multitudes of wild pigeons in our woods are astonishing.  Indeed, after having viewed them so often, and under so many circumstances, I even now feel inclined to pause, and assure myself that what I am going to relate is fact.  Yet I have seen it all, and that too in the company of persons, who, like myself, were struck with amazement.

In the autumn of 1813, I left my house at Henderson, on the banks of the Ohio, on my way to Louisville.  In passing over the barrens a few miles beyond Hardensburgh, I observed the pigeons flying from north-east to south-west, in greater numbers than I thought I had ever seen them before, and feeling an inclination to count the flocks that might pass within the reach of my eye in one hour, I dismounted, seated myself on an eminence, and began to mark with my pencil, making a dot for every flock that passed.  In a short time finding the task which I had undertaken impractical, as the birds poured in countless multitudes, I rose, and counting the dots put down, found that 163 had been made in 21 minutes.  I traveled on, and still met more the farther I proceeded.  The air was literally filled with pigeons; the light of the noon-day was obscured as by an eclipse; the dung fell in spots, not unlike melting flakes of snow; and the continuing buzz of wings had a tendency to lull my senses to repose…

“It may not, perhaps, be out of place to attempt an estimate of the number of pigeons contained in one of those mighty flocks, and of the quantity of food consumed by its members.  The inquiry will tend to shew the astonishing bounty of the great Author of Nature in providing for the wants of his creatures.  Let us take a column of one mile in breadth, which is far below average size, and suppose it passing over us without interruption for three hours, at the rate mentioned above as one mile in a minute.  This will give us a parallelogram of 180 miles by 1,  covering 180 square miles.  Allowing two pigeons to the square yard, we have one billion, one hundred and fifteen million, one-hundred and thirty-six thousand pigeons in one flock.  As every pigeon daily consumed fully half a pint of food, the quantity necessary for supplying this vast multitude must be eight million seven hundred twelve thousand bushels per day.”

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Some archaeologists believe the massive population of passenger pigeons that colonists in North America reported from 1700-1870 was a temporary phenomenon.  Thomas Neuman has written at least two journal articles suggesting passenger pigeon populations exploded following the decimation of Indians after their first contact with European diseases such as smallpox, influenza, and measles.  Before this, Dr. Neuman believes this species was not particularly common.  Supposedly, when Indian populations were reduced, there was more forest mast available for birds because humans weren’t gathering the nuts and acorns they fed upon.  In his book 1491 Charles Mann discusses this theory and notes that archaeologists find few passenger pigeon bones at sites of large Indian settlements.

I disagree with this theory because it makes little sense for several reasons which I shall enumerate.

1. Passenger pigeons could not survive as a species unless they existed in extremely large populations.  The survival strategy of this species was to reproduce rapidly and roost and nest in enormous colonies so that they overwhelmed predation.  Predators ate many individuals, but there was a limit to how much their stomachs could hold.  If, as these archaeologists suggest, the passenger pigeon was just an occasional bird, the species would’ve become extinct long before the white man arrived on the continent because their defense mechanisms revolved around living in large colonies.

2. Even if human populations were at the high end of what archaeologists believe, they would’ve made little impact on the amount of forest mast available.  Pre-Columbian forests were extensive, and there was always plenty of forest mast for both humans and huge pigeon colonies.

3. Archaeologists don’t find many passenger pigeon bones in sites of large Indian settlements because Indians probably went to their roosting grounds and feasted on them there and simply didn’t bring the bones back to their villages.

4. Jacques Cartier, an early explorer, reported large pigeon colonies on Prince Edward Island in 1534…before Indian populations were reduced by disease.

5. Pigeon fossils are abundant in an early Holocene fossil site in Western Canada (Charlie Lake, British Columbia).  They are also a common fossil in late Pleistocene avifaunas including Bell Cave, Alabama, Cheek Bend Cave, Tennessee, and Ladds and Kingston Saltpeter Cave in Georgia.

At Ladds fossils of only 4 bird species were discovered.  Passenger pigeons were 1 of the 4.  This may be coincidence, but it’s believed that passenger pigeon biomass made up 25% of all bird populations in North America during the early part of the 19th century.  Many more species of birds were found in the deposit at Kingston Saltpeter Cave.  I compared the minimum number of individual passenger pigeon fossils from KSC to the total bird remains of all other species found there.  Ruffed grouse were the most common species, making up 30% of bird remains, but passenger pigeons made up 6%, despite being a highly migratory bird.  Assuming they spent 6 months of the year around KSC, that means at times, they may have made up to 12% of the bird population in the area.  If they stayed in the area around the cave for only 2 months of the year, they quite possibly made up 36% of the bird population at certain times of the year there.

I must mention, however, that estimating ancient bird populations based on the number of bird fossils found in cave deposits is a rather dubious method.  Nevertheless, habitat for passenger pigeons in southeastern North America during the Pleistocene must have been ideal for this species.

During colonial times this bird nested throughout the midwest, but spent September-February in southeastern states.  For much of the duration of the Wisconsin Ice Age, most of the area where they later nested was under glacial ice, so it’s likely their nesting areas shifted south.  They probably were year round residents everywhere south of the Laurentide ice sheet, except during nesting season when they nested in southern river bottomlands where beech and oak trees remained plentiful, even during cold arid climatic phases.

Today, beech trees are a rare relic in much of the southeast, but during certain climatic phases of the Wisconsin Ice Age, they were even a dominant tree on some lands, according to records of fossil pollen in Alabama, and South Carolina.  From 14,000-11,000 years BP beech was a common tree, while pine, which dominated southern forests during the LGM, temporarily declined drastically.  Beech is well adapted to pigeon and squirrel foraging because this tree spreads through sucker roots, and if animals eat the tree nuts, this species can still propagate.  Beech tree pollen is also present in the Nodoroc fossil site in central Georgia near Winder and at the Gray’s Reef site off Sapelo Island, which was above sea level 30,000 years ago.  The latter site yielded evidence of a forest consisting of a strange mixture of cool temperate and warm weather species of plants.  The south’s Ice Age ecosystem was a mixture of woodlands and grasslands, and it provided excellent habitat for passenger pigeons.  I think the expansion of southern beech tree forests, as the Ice Age waned, is evidence the population of pigeons may have spiked about 14,000 years BP, creating the nucleus that later colonized the midwest after the glacier melted and broadleaf trees re-established themselves there.

References.

Driver, J.C.; and K.A. Hobson

“A 10,500 year sequence of bird remains from the southern boreal forest region of western Canada”

Arctic 45 (2) 1992

Ellsworth, Joshua; and Brenda McComb

“Potential effects of Passenger Pigeon flocks on the structure and composition of pre-settlement forests of eastern North America”

Conservation Biology 17 (6) pp. 1548-1558 2003

Mann, Charles

1491

Knopf 2005

www.paleodb.org

Cougars vs. Jaguars

July 8, 2010

Cougars and jaguars co-existed for at least 500,000 years throughout North America, and today still co-exist in many areas of South America and Mexico.  Both species are adaptable enough to occupy a wide variety of environments, including deserts, lightly wooded savannah, flooded swamps, and tropical rain forests.  They also feed upon many of the same prey species.  This spawns two questions: what ecological differentiation allows two big cat species to co-occur on the same range, and what factors allowed cougars to remain in much of North America where jaguars were extirpated?  A number of scientific studies help solve these ecological mysteries.

Comparison of cougar and jaguar diets

Studies of jaguar and cougar diets consistently show significant differentiation.  Although cougars and jaguars tackle many of the same species, the latter selects for larger sized individuals.  One study of co-occurring jaguar and cougar populations in Venezuala–a region consisting of woodland, savannah, and swamp–found the following differences in prey size selection between the two species.

…………………………………….Cougars……………………………Jaguars………………

Small size prey…………………17%……………………………………1%……………….

Medium size prey……………..31%……………………………………14%……………..

Large prey……………………….52%……………………………………85%…………….

For example in this region collared peccaries are an important diet item for both species, but cougars exclusively take small juveniles, while jaguars take mostly adults and sub-adults.  Both big cats took a wide range of prey species with cougars taking 12 different kinds of animals and jaguars taking 10.  Jaguars preyed more heavily upon capybaras here than cougars did.  Jaguars also preyed upon white-lipped peccaries–an aggressive species that cougars completely avoided.  White-lipped peccaries live in large groups and frequently come to the aid of their comrades and attack predators.  They’ve been known to kill jaguars and even humans.

Illustration by John James Audubon

Another study of jaguar diet, this one in southern Brazil where flooded plains are the predominant habitat, found that the jaguar diet there included 31% cattle, 24% caiman, 21% peccary, 4% feral hog, 3.0% marsh deer, 3.2% giant anteater, 2% capybara, 1.6% brocket deer, and about 10% other.  438 prey items were recorded, showing that jaguars will take what’s generally available.  Incidentally, both jaguars and cougars are capable of killing the alligator-like caiman, but take them less than would be expected based on their abundance.

Illustration by John James Audubon

A third study, this one in Mexico where both jaguars and cougars mostly prey on deer, peccary, and armadillo, also found that jaguars select for larger prey items.  This study concludes that the “cougar’s ability to exploit smaller prey gives them an advantage over jaguars when faced with human-induced habitat changes.”  This conclusion brings to obvious light one of the reasons why cougars survived throughout much of North America where jaguars didn’t.  After Indians overhunted much of North America’s megafauna, jaguars had difficulty finding the larger prey they preferred.  The extinction of two Pleistocene species of peccary in North America was probably devastating.  Indians even overhunted white tail deer into scarcity as John Lawson, an early European explorer (circa 1704) noted when he pointed out that deer were rare around large Indian settlements in South Carolina.  But cougars could survive in these areas on rabbits, possums, raccoons, and turkeys.

I agree that the preference for larger game that no longer exists is one factor that’s limited the jaguar’s range in North America, but I think there are other factors.

Evolution of size, coat color, adaptability to cold, and personality traits

The fossil record suggest jaguars, along with dire wolves, were the most common large carnivores (excluding omnivorous bears) in southeastern North America during the Pleistocene.  Yet, cougars found their niche here too.  During the Pleistocene both species were somewhat larger than the present day versions of these species.  Rancho La Brean specimens of cougars show that on average they were 5% larger than those of today, while Pleistocene jaguars approached modern day tigers in size.  I think this is due to the larger size and quality of prey available, particularly horses and the larger sized species of peccaries, and it’s clear these two big cats not only had a better diet, but further impetus to evolve to a greater size, so they could successfully exploit this larger prey.  One study reported that modern jaguars living in areas where cattle were introduced tend to approach the size of the larger Pleistocene jaguars, and it’s believed that jaguar populations increased following the introduction of European livestock to South America.

I theorize the spotted coat of the jaguar is another factor in its range reduction.  Indians valued the beauty of its fur and hunted them unmercifully.  There’s a possibility that Pleistocene cougars had spotted coats.  Scientists believe that cougars evolved from a kind of spotted cheetah.  Cougar kittens retain these cheetah-like spots–evidence of this evolution.  But I think many adult cougars may have been spotted until very late in the Pleistocene when man colonized the continent and hunted the spotted cougars for their coats, leaving only the dull tawny and gray coated individuals to breed, which in turn genetically swamped the spotted ones.

It has been suggested that spotted cats are more vulnerable to cold climate–another factor which may limit the jaguar’s range, but I disagree with this hypothesis.  The snow leopard of the Himalayas is an example of a spotted cat that lives in a cold region.  Moreover, jaguar fossils have been excavated from as far north as Oregon and Pennsylvania when even during the warmest interglacials, subfreezing temperatures occurred during winter. 

Jaguar fossils in Georgia have been excavated from Ladds Quarry and Kingston Saltpeter Cave.  A nearly complete skull was recovered from the former location along with giant tortoise and armadillo bones that have jaguar gnaw marks on them.  Fossils from this period probably date to a warm climate phase, but the jaguar remains from KSC are associated with the kinds of animals that live in cold and temperate climates, indicating jaguars survived colder conditions than any endured by extant populations.  Cougar fossils also were found at Ladds and in Yarbrough Cave which dates to the last glacial maximum.

One more factor in the cougar’s survival where jaguars didn’t may be evolutionary selection towards more timid individuals.  Those members of the cougar population that learned to avoid man were more likely to survive.  Timidity possibly occurred less frequently in prehistoric jaguar populations.

Cougars vs. Jaguars, wolves, and bears

So which would win in a battle between a jaguar and a cougar?  According to scientific studies, cougar and jaguar ranges frequently overlap, but they tend to avoid each other.  Certainly, a jaguar wouldn’t think it worth the effort to battle a raging mother cougar defending her kittens.  Conversely, a cougar would be out of its mind to engage in a battle with a larger, more powerful cat that bites harder than any other kind of cat in the world.  However, in one paper, international big cat expert, Howard Quigley, did cite a case of a jaguar attacking and killing a cougar.

Packs of wolves also dominate cougars in the Rocky Mountains.  Wolves occasionally kill cougar kittens, sub-adults, and even adults.  The average biomass of wolves in packs that attack a cougar outweighs the cat by a 13:1 ratio.  Rarely, cougars have been reported to kill wolves (sub-adults and adults, but not pups), but in these cases it was one-on-one and the biomass was a 1:1 ratio.  A certain percentage of cougar kills are lost to wolves and bears in areas where their ranges overlap.

References

Carvolcanti, Sandra; and Eric Gese

“Kill rates and predation patterns of jaguars (Panthera onca) in the southern pantanal of Brazil”

Journal of Mammalogy 91 (3) 722-736 2010

Hoogesteyn, Rafael; and Edgardo Mondolfi

“Body mass and skull measurements in four jaguar populations and observations on their prey base”

Bulletin of the Florida Museum of Natural History V. 39 (6) pg. 195-219 1996

Hornocker, Maurice; Sharon Negri, and Alan Rabinowitz

Cougar: Ecology and Conservation

University of Chicago Press 2002

Nunez, Rodrigo; Brian Miller, and Fred Ludjey

“Food habits of jaguars and cougars in Jalisco, Mexico”

Journal of Zoology 252 (3) 373-379

Scognamillo, Daniel; et. al.

“Co-existence of jaguar (Panthera onca) and puma (Puma concolor) in a mosaic landscape in the Venezualan llanos”

J. Zoological Society of London 259 269-277 2003