Melanistic canids, jaguars, and squirrels

July 18, 2014

Melanism in North American wolves is an ancient trait, that according to 1 genetic study, originated from an hybridization event between Eurasian wolves (Canis lupus) and primitive dogs (Canis familiaris).  This occurred at least 46,000 years ago, predating the actual domestication of dogs.  At this early date primitive dogs probably varied from wolves in their preference for living in close proximity to human habitation.  The differences between dogs and wolves then were even less than they are today, and hybridization was much more likely to occur.  Eurasian wolves crossed the Bering landbridge and brought this trait for melanism with them, but curiously, wolves in Eurasia with the trait for melanism died out.  The only population of wolves in Europe today that carry the trait for melanism live in Italy, and this is thought to derive from a much more recent hybridization with dogs.  In North America hybridization between western wolves and dogs no longer occurs in the wild, or at least that’s what the evidence suggests.

Black-coated predators are harder for prey to see in deep shady forests.  Therefore, forested environments provide a natural selection mechanism that favors melanistic individuals.  The incidence of melanistic canids is greater in deep forests than in open environments.  In Alaska dark wolves are rare in open tundra but common in adjacent boreal forests–a great example of natural selection.  Melanism in coyotes (Canis latrans) is extremely rare in western North America but common in the east, especially in the south.  Having darker colored fur is a beneficial mutation for a predator living in the more heavily forested southeast.  

Taxidermic mount of a melanistic coyote killed near Cedartown, Georgia.  This looks identical to the so-called red wolves that were formerly found in Florida.  Is this evidence the wild canids formerly living in the south were not completely extirpated and have bred this melanistic gene into the western coyotes that have colonized the region within the last 50 years?  I believe the wolves that used to live in the south were merely eastern coyote x primitive dog hybrids.

Melanism in eastern coyotes also is derived from hybridization with dogs.  In the past  male dogs mated with  female coyotes and the hybrids backcrossed into the coyote population.  This occurred prior to when coyotes recolonized the south about 50 years ago.  I suspect the southeastern wolves in North America during the time of European colonization were merely hybrids between eastern coyotes and the primitive dogs brought over by Indians about 13,000 years ago.  These primitive dogs, known as the American dingo, readily revert to a wild state, and some likely bred with eastern coyotes during the late Pleistocene/early Holocene.  These hybrids took over the ecological niche left vacant when dire wolves became extinct.  Evidence from 500 year old wolf remains found in Ontario, Canada show the eastern wolf had DNA sequences from both dogs and coyotes but not from western gray wolves.  Yet, morphologically they resembled wolves.  Eastern Canadian wolves probably had a similar origin as southeastern wolves.

Melanism is also common in 2 species of big cats that favor heavily forested environments.  In jaguars (Panthera onca)melanism is conferred through a dominant allele, while in leopards (Panthera pardus) it is conferred through a recessive allele.  When a spotted jaguar mates with another spotted jaguar, the cubs are always spotted.  Cubs from a pairing of a spotted jaguar and a black jaguar can be either spotted or black.  Melanism is also associated with beneficial mutations in the immune system.  This probably also explains the increased incidence of black jaguars in jungles where tropical diseases are prevalent.  Melanistic margays, ocelots, and jaguarundis are known to occur, but no proven specimen of a melanistic cougar has ever been confirmed.  However, cougars in south Florida are grayish, and this coloration affords them a similar advantage enjoyed by completely melanistic cats. 

I hypothesize that Smilodon fatalis, the saber-tooth cat, may have had some melanistic individuals in regions with deep forests.  It was an ambush predator, and a black coat would have made them difficult to spot, especially at night.  Artists rarely portray them with a black coat.  There is enough genetic material at the La Brea tarpits museum to determine whether or not Smilodon carried this trait, but so far, no scientist has thought to look for it.

Melanistic jaguar, showing that markings are visible

Melanistic jaguar–a real black panther.

Fox squirrels (Sciurus niger) are frequently found in melanistic color phases.  One study found that the higher incidence of black color phases in fox squirrels correlates positively with the higher frequency of lightning-induced wildfires in longleaf pine savannahs.  Apparently, the scorched black ground provides camouflage for fox squirrels from 1 of their most common predators, the red-tailed hawk.  Longleaf pine savannahs are often burned annually, and the ground stays black for long enough periods to select for melanistic individuals. 

Melanistic fox squirrel and deer fawn.

Melanistic gray squirrels(Sciurus carolinensis) were formerly abundant when much of North America was covered by shady deep forests.  Today, the black phase of the gray squirrel is still locally common in some midwestern states and CanadaThe black fur conveys an advantage in colder climates, helping the animals warm in the sun.  Individuals of this color phase have been widely relocated, and some populations exist as far south as Kentucky and Washington DC.

References:

Adams, J.R.; and Leonard Waits

“Widespread Occurrence of Domestic Dog Mitochondrial DNA Haplotype in Southeastern, USA, Coyotes”

Molecular Ecology 12 2003

Anderson, J.R.; et. al.

“Molecular and Evolutionary History of Melanism in North American Gray Wolves”

Science 323 2009

Kiltie, R.A.

“Wildfire and the Evolution of Dorsal Melansim in Fox Squirrels, Sciurus niger

Journal of Mammalogy 70 1989

Mowry, Christopher; and Justin Edge

“Melanistic Coyotes in Northwest Georgia”

Southeastern Naturalist  13 (2) 2014

Rutledge, Linda; et. al.

“Genetic and Morphometric Analysis of 16th Century Canis Skull Fragments: Implications for Historic Eastern Gray Wolf Distribution in North America”

Conservation Genetics 2010

Did Eremotherium laurillardi Supplement its Diet with Sea Weed?

July 13, 2014

Eremotherium laurillardi, a species of giant ground sloth, apparently was abundant along the Georgia coast during the Sangamonian Interglacial (~132,000 BP-~118,000 BP).  Fossils of this species have been found at 7 of the 9 known coastal fossil sites of Pleistocene Age. It was really a spectacular beast growing as large as 18 feet long and weighing 6000 pounds.  When it sat on its haunches, it was even taller than a mammoth.  It disappeared from the state when the climate turned colder, probably some time between ~75,000 BP-~30,000 BP.  The fossil record is too incomplete to determine exactly when this species succombed to the cold in this region.  Eremotherium continued to exist in South America until the end of the Pleistocene.  Two other species of ground sloths  were better adapted to the cold and likely lived in Georgia as recently as 11,000 BP.  Jefferson’s ground sloth (Megalonyx jeffersonii) and Harlan’s ground sloth (Paramylodon harlani) were able to survive subfreezing temperatures by denning in underground burrows. (See: http://markgelbart.wordpress.com/2012/10/10/some-giant-ground-sloths-dug-long-burrows/).

eremotherium and human

Size comparison between Eremotherium laurillardi and a man

Eremotherium primarily ate leaves and twigs.  However, I wonder if they supplemented their diet by foraging on seaweed that washed upon the beach.  Because this species frequented the coast, I’m sure they knew how to swim and may have colonized areas of the mainland or islands by crossing waterways with a depth above their head.  Seaweed is high in certain minerals such as iodine and sodium that are lacking in tree leaves.  Modern day tree sloths are known to obtain these nutrients by raiding human septic tanks to feed on feces.  If Eremotherium ate seaweed, scientists should be able to find abrasions on their teeth from munching seaweed with sand adhering to it.  The scientific literature is silent about this detail, but that may be because scientists have never looked for this evidence.

i-f37fe4c608a50b25cc6d49e7bfdc9d9a-toilet_sloth_M-Stojan-Dolar_April-2010.jpg

Two-toed tree sloth, Choloepus didactylus, climbing from a latrine where it just enjoyed snacking on human shit.  The minerals excreted by humans supplement the diet of this species which consists of tree leaves low in sodium.

There was a genus of South America ground sloths that did gradually evolve into an increasingly aquatic existence.  Five consecutive species of ground sloths in the Thalossocerus genus lived on the coast of Chile and Peru between 9 million years BP-4 million years BP.  The earliest species was Thalossocerus antiquus and the last was T. yaucensis T. antiquus had a shorter nose and abrasions on its teeth from eating seaweed with sand adhering to it.  It likely foraged on the beach and in shallow water.  T. yaucensis had a longer nose and no abrasions on its teeth–evidence it swam deeper into the ocean to feed upon kelp that was washed free of sand by the currents.  Moreover, T. yaucensis had greater bone densisty, a characteristic found in marine mammals; and their anatomy suggests they had strong lips for plucking underwater plants.  Manatees have similarly strong lips.  The environment in this region then was mostly desert, so evolving the ability to subsist mostly on seaweed facilitated the survival of this species in an otherwise uninhabitable landscape.  This genus became extinct at the end of the Pliocene during a major marine extinction event.

Thalassocerus sp., a marine ground sloth that lived on the coast of what’s now Chile and Peru between 9 million BP-4 million BP.  Although Eremotherium also lived near the coast, it probably did not swim in the ocean as regularly as this species.

I propose to any vertebrate paleontologists who read this blog, to check your Eremotherium specimens for sand abrasions.  Maybe you can publish a paper about it and thank me for bird-dogging the idea.

Reference:

Amsen, Eli; et. al.

“Gradual Adaptation of Bone Structure to Aquatic Lifestyle in Extinct Sloths from Peru”

Proceedings of the Royal Society of Science 281 (1782) 2014

William Bartram’s Visit to St. Simons Island in 1774

July 10, 2014

I didn’t go to St. Simons Island this summer as I’d initially planned, but I wasn’t disappointed.  I’m sure the island is not as interesting as it was when William Bartram visited it in the spring of 1774.  Bartram stayed for a few days with James Spalding, then the president of the settlement of Frederica and a merchant involved in the Indian trade.  Although a remnant of an old growth maritime forest has been preserved for the modern day naturalist to enjoy, Bartam had the opportunity to see the island when it was mostly undeveloped.  One day, he left Frederica on horseback to survey the island.  Thick groves of live oaks surrounded the town.

500 year old live oak on John’s Island South Carolina.  There may have been quite a few trees of this age on St. Simons Island when Bartram visited in 1774.

Bartram rode through the virgin live oak woods and found a “beautiful green savannah” about 2 square miles in extent.  Long-horned cattle, horses, sheep, and deer fed in this natural pasture.  On the other side of this savannah, he followed an old road that had fallen into disrepair.  The road went through an open woodland of live oaks and longleaf pines spread far enough apart that grass and shrubs could grow in the understory.  The road ended after 5-6 miles when he reached an impenetrable thicket growing on a sandhill.  The thicket was composed of live oak, myrtle, holly, beautyberry, silverbell, alder buckthorn, hoptrees, bully trees, hornbeam, and bignonia.  Several of these species are evergreen and subtropical.  Greenbriar vines covered the thicket, and there was a salt marsh on the other side of the sandhill.  Bartram referred to it as a “salt plains.”

Bartram did find a freshwater creek between the forest and the salt marsh.  Here, he rested and enjoyed the fragrant beauty of diamond frost, morning glory, lycium (a thorny plant in the nightshade family), scarlet sage, and white lily; all of which were blooming in April.

Diamond Frost Euphorbia Diamond frost in the Euphorbia genus.  It is related to the more famous Christmas poinsetta.  This is one of the flowers Bartram saw growing on St. Simons Island.  Actually, it is the leaves that look like flowers. 

Bartram turned south and found the beach where he saw living and dead starfish, corals, jellyfish, snails, whelks, clams, and squid; all washed upon the sand.  He left the uninhabited beach and headed west, coming across 50-60 beehives lined up in a grove of oaks and palms.  He met a farmer and beekeeper who was resting upon a bearskin rug after a morning spent hunting and fishing.  The man gave Bartram venison and honey-sweetened water spiked with brandy.  They had a picnic amidst the mockingbirds, painted buntings, and hummingbrids.  Jasmine, honeysuckle, and azaleas scented the air. 

William Bartram met a farmer and beekeeper on St. Simons Island who was lounging outside on a beer skin rug while drinking brandy mixed with honey and water.  He must have caught the bear raiding his bee hives.

 ©Zachary_Huang 

An apiary.  Beekeepers and bears do not get along.

On his way back to Frederica, Bartram saw many abandoned plantations.  Even Fort Frederica itself, still manned at the time by a small garrison, was falling apart.  Peach, fig, and pomegranate trees grew through the broken walls.  General Oglethorpe had ordered the construction of the fort 60 years earlier, but funds in 1774 were not available to maintain it.

Fort Frederica on St. Simons Island, Georgia.  General Oglethorpe ordered it built circa 1712 to repel any possible invading colonial force such as the Spanish.  By 1774 it was already in ruins.

I envy the bucolic life of the farmer that Bartram met.  The man had half of St. Simons Island to himself.  For an 18th century existence, this was living in paradise.  Poor city folks in London then were lucky if they had bread.  But this man lived on a beautiful plantation with quite a variety of food available from both land and sea.  On the other hand, he didn’t have air conditioning and television.  And the bikini had yet to be invented.  Today, his plantation has been transmogrified into a landscape of condos built as closely together as possible.  If this farmer could visit the present day for a week, I wonder if he would envy our modern life as I envy his or would he wish to return to his old life.  I wonder…would he trade places with me?

The Isle of Hope Fossil Site in Chatham County, Georgia

July 6, 2014

I’ve mentioned the Isle of Hope fossil site numerous times on this blog, but I recently realized I’ve never featured it.  In my opinion it is the 3rd or 4th best Pleistocene fossil site in Georgia, ranking behind Ladds, Kingston Saltpeter Cave, and perhaps Yarbrough Cave.  More vertebrate fossils were discovered here than at any other coastal fossil site in Georgia.  Most other coastal fossil sites were discovered in the 18th or 19th centuries before paleontologists screen-washed sediment for smaller bones, and accordingly the earlier scientists only collected bones of the largest species.  The more recently discovered Clark Quarry near Brunswick may rival the Isle of Hope for best coastal site, but despite the publication of a preliminary report in 2005, the finds at this site have yet to be thoroughly and systematically reviewed in a scientific journal.

The Isle of Hope is an elite neighborhood in Savannah, Georgia.  At high tide, it is separated from the mainland by a small tidal river.  Vertebrate fossils of Pleistocene age have been collected from this river.

The Isle of Hope fossil site was a deposit that occurred on both sides of a small tidal river within the city limits of Savannah.  During high tide this rivulet separates the island from the mainland.  The fossil site was discovered in the early 1980s during construction of a boat pier.  The landowners, and John Heard, an amateur hobbyist, collected the fossils, and later, paleontologists from Georgia Southern also collected specimens from the site.  Most of these specimens are housed at the Georgia Southern Museum.  One side of the site has been “covered in riprap and is no longer accessible for collection.”   However, I suspect this entire tidal river has potential for a hobbyist prospecting for fossils  Tidal action has likely distributed specimens in both directions away from the deposit.  If I lived in Savannah, I’d definitely search for fossils here.

Uranium-series dating and fossil composition suggest the fossils were deposited during a warm interglacial climate phase between ~132,000 BP-~75,000 BP.  Every single species of mollusc and fish found in the fossil deposit still occurs in the region today–evidence water temperatures during this climatic stage were similar to those of today. 

The dwarf surf clam was the most common bivalve species found at the Isle of Hope site.  It is still the most numerically common clam in Georgia tidal inlet channels.

user posted image

Fossil brown-banded wettletraps were found at the Isle of Hope site.

Atlantic sharpnose shark

The Atlantic sharp-nosed shark.  Fossils of this species were the most common fish remains found at the Isle of Hope site.  It’s still the most common shallow water shark found in the region today.

Amazingly, the fishing in coastal Georgia 100,000 years ago would have resulted in the same species typically caught from a modern day pier–sharp-nosed sharks, stingrays, moray eels, sheepshead, black drum, toad fish, and puffers.  Schools of mullet would have been seen swimming by, and little killifish swarmed the shallows.

Eastern mud turtle.  Mud turtles were the most common reptile specimens found at the Isle of Hope site. 

 Photo of Salt Marsh Vole. Photo courtesy of USFWS/Photo by Michael Mitchell.

The meadow vole was the most common small mammal living in coastal Georgia during the Pleistocene.  This species no longer occurs this far south aside from a relic population that lives in a salt marsh in Levy County, Florida.  

There has been an interesting change in the small mammal fauna of coastal Georgia since the Pleistocene.  Then, the most common rodents were the arvicolines, including the meadow vole, southern bog lemming, and Florida muskrat.  The sigmodontine rodents (cotton rat, rice rat, wood rat, and old field mouse) were present but less common.  Today, the 3 arvicoline rodents mentioned above are absent from coastal Georgia while the sigmodontine rodents are common.  The bog lemming no longer occurs this far south.  The meadow vole also doesn’t occur this far south with the exception of a relic population that lives in a salt marsh in Florida.  The Florida muskrat no longer occurs this far north.  Scientists believe the intermingling of warm and cold climate species during the Pleistocene is evidence that climate then was more equible than it is today because formerly winters were warmer and summers were cooler.  I have a different explanation for the co-existence of warm and cold climate species during the Pleistocene.

During some climatic phases, average temperatures were less extreme than they are today, but overall climatic fluctuations were formerly more drastic.  These dramatic climatic fluctuations created more varied habitats that supported a wider array of fauna, especially of small mammals. I think the relatively stable climate of the past 10,000 years is the cause of the more zonal distribution of small mammal species today.  The change in temperature ranges between the Pleistocene and Holocene haven’t been large enough to entirely explain the disappearance of arvicolines from coastal Georgia.  Instead, I think a shift to a more stable climate pattern is a better explanation.  For example, during the Pleistocene a shift to a sudden cold pattern with snowy conditions would have benefited meadow voles over cotton rats because the former are better adapted to living under snow.  A subsequent shift to warm climate would have favored cotton rats, but during Ice Ages the warm climatic phases didn’t last long enough to completely extirpate the cold climate species.  Changes in species composition lagged behind the rapid climatic changes. But over the past 10,000 years, a warm climatic phase that has lasted quite a while, meadow voles did not enjoy the benefits of a sudden shift to cold climate in the south and have mostly disappeared from the region.  Only species adapted to warm climate have been able to continue living in the south.

Perhaps the most mysterious mammal to have lived in Georgia 100,000 years ago was a small cat.  (See http://markgelbart.wordpress.com/2013/05/09/the-mystery-cat-of-pleistocene-georgia/).  A jaw bone of this species was found at this site but not enough skeletal material has been found to determine what species this cat was.  Despite the genus name, Leopardus, it was not closely related to the leopard as some sources have erroneously and carelessly reported (See Roadside Geology of Georgia).  Instead, it was closely related to the margay and ocelot.

White-tailed deer fossils were the most abundant large mammal specimens found here.  Deer may have been more common in Pleistocene Georgia than other species of now extinct megafauna, contrary to other areas such as Florida.  However, specimens of long-nosed peccary, bison, horse, tapir, and mastodon have been found here, showing they did share the environment with deer.  I think if this tidal river were more throughly investigated, fossils of more species would be  discovered, including those of large carnivores which are so far lacking completely from coastal Georgia sites.

Eremotherium laurillardi, the giant ground sloth.  It was common on the Georgia coast during the last interglacial but disappeared from North America some time during the following Ice Age.

Below is a list of all the species found at the Isle of Hope site as reported in the reference cited at the bottom.  I had fun translating the Latin names to English.  Just 1 species of shellfish stymied my attempt to translate them all.

Isle of Hope Species List

Knobbed whelk (Busycon carica)

Brown-banded wettletrap (Epitonium rupicola)

Sea snail (Eupleura caudata)

Lettered olive (Oliva sayana)

Sea snail (Polinices duplicatus)

Eastern auger (Terebra dislocata)

Small white clam (Abra aequalis)

Incongruous ark clam (Anadara brasiliana)

Blood ark clam (Anadara ovalis)

Transverse ark clam (Anadara transversa)

Common jingle shell (Anomia simplex)

? (Divaricella quadrisulcata)

Coquina clam (Donax variabilis)

Dwarf surf clam (Mulinia lateralis)

Ponderous ark clam (Noetia ponderosa)

Atlantic nut clam (Nucula proxima)

3-toothed Cardita (Pleuromeris tridentata)

Nurse shark (Ginglymostoma cirratum)

Sand tiger shark (Carcharias taurus)

Tiger shark (Galeocerdo cuvier)

Bull shark (Carcharhinus leucas)

Dusky shark (Charcharhinus obscurus)

Lemon shark (Negaprion brevirostris)

Sharp-nosed shark (Rhizoprionodon terranovae)

Hammerhead shark (Sphyrna tiburo)

Stingrays (Dasayatidae)

Spotted eagle ray (Aetobatus narinari)

Eagle rays (Myliobatidae)

Gar (Lepisosteus sp.)

Lady fish (Elops saurus)

Moray eels (Muraenidae)

Shad (Alosa sp.)

Herrings (Clupeidae)

Hard-nosed catfish (Arius felis)

Lizard fish (Synodus sp.)

Toadfish (Opsanus sp.)

Ray-finned fish (Batrachoididae)

Killifish (Fundulus sp.)

Sea robins (Prionatus sp.)

Cutlass fish (Trichiurus sp.)

Pinfish (Lagodon rhomboides)

Sheepshead (Archosargus probatocephalus)

Silver Perch (Bairdella cf chrysoura)

Black drum (Pogonias cromis)

Red drum (Scianops ocellata)

Mullets (Mugil sp.)

Barracudas (Sphyraena sp.)

Flounders (Bothidae)

Boxfish (Lactophrys sp.)

Puffer fish (Tetraodontidae)

Porcupine fish (Diodontidae)

Siren (Siren intermedia)

Red Spotted Newt (Notophthalmus viridescens)

Conger Eel (Amphiuma means)

Spotted Salamander (Ambystoma cf maculatum)

Toads (Bufo sp.)

Chorus frog (Pseudacris ornata)

Bullfrog (Rana catesbeiana)

Snapping Turtle (Chelydra serpentina)

Mud Turtles (Kinosternon sp.)

Musk Turtles (Sternotherus)

Soft Shelled Turtle (Apalone ferox)

Box turtle (Terrapene carolina)

Chicken turtle (Deirochelys reticularian)

Slider (Pseudemys cf concinna)

Pond slider (Trachemys scripta)

Gopher tortoise (Gopherus polyphemus)

Extinct Intermediate Tortoise (Hesperotestudo incisa)

Extinct Giant Tortoise (H. crassicutata)

Black Racer (Coluber constrictor)

Bull Snake (Pituophis melanoleucas)

Water snake (Nerodia fasciata)

Queen snake or other Crayfish snake (Regina sp.)

Garter snake (Thanophis sirtalis)

Hog-nosed snake (Heterodon sp.)

cottonmouth water moccasin (Agkistrodon piscivorus)

unidentified rattlesnake (Crotalus sp.)

Unidentified duck (Anas sp.)

Opposum (Didelphis virginiana)

Beautiful armadillo (Dasypus bellus)

Giant ground sloth (Eremotherium laurillardi)

Harlan’s ground sloth (Paramylodon harlani)

Short-tailed shrew (Blarina brevicauda)

Southeastern shrew (Blarina carolinensis)

Eastern mole (Scalopus aquaticus)

Unidentified bear (Ursidae)

Raccoon (Procyon lotor)

River otter (Lutra canadensis)

Margay-like cat (Leopardus sp.)

Bobcat (Lynx rufus)

Southern flying squirrel (Glaucomys volans)

Gray squirrel (Sciurus carolinensis)

Beaver (Castor canadensis)

Rice rat (Orzomys palustris)

Cotton rat (Sigmodon hispidus)

Wood rat (Neotoma floridana)

Old-Field Mouse (Peromyscus polionotus)

Florida muskrat (Neofiber alleni)

Southern bog lemming (Synaptomys australis)

Meadow vole (Microtus pennsylvanicus)

Pine vole (M. pinetorum)

Cottontail rabbit (Sylvilagus floridanus)

Marsh rabbit (S. palustris)

Long-nosed peccary (Mylohyus fossilis)

Bison sp. (Bison sp.)

White-tailed deer (Odocoileus virginianus)

Tapir (Tapirus veroensis)

Horse (Equus sp.)

Mastodon (Mammut americanum)

Reference:

Hulbert, Richard; and Ann Pratt

“New Pleistocene (Rancholabrean) Vertebrate Faunas from Coastal Georgia”

Journal of Vertebrate Paleontology 18 (2) June 1998

 

 

Kites of Southeastern North America

July 3, 2014

I judge the quality of my vacations based on how much wildlife I see.  The best time to view wildlife is early in the morning, but I’m saddled with a late-sleeping teenaged daughter.  I’ve given up even trying to get an early start.  However, at home in Augusta, Georgia, I’ve had better luck lately.  The other day I was jogging on the road in front of my house and thought I saw a pair of cuckoos flying but they went by too fast for me to make a positive ID.  Later that afternoon, I did hear the unmistakeable call of a cuckoo in the woods behind my house and have since heard them twice more. (http://www.allaboutbirds.org/guide/yellow-billed_cuckoo/sounds)  I believe the cuckoos are nesting there.  I hope they eat the hornworms that ravage my tomato plants, and the tent caterpillars that chew up my blueberry bushes.  Cuckoos eat caterpillars that other birds find distasteful. 

One morning, I saw a Cooper’s hawk fly directly toward my back window before veering away.  Red-tailed and red-shouldered hawks are common in my neighborhood, but this was the first Cooper’s hawk I have ever seen in Augusta and I have lived here for 37 years.  During summer, I almost always see Mississippi kites soaring high over me when I’m suffering through my morning jog.  I saw 6 along with a black vulture last Saturday.

Mississippi kite.  Usually, they soar so high, I can’t see their color pattern.

Mississippi kites (Ictinia mississippiensis) are summer residents of southeastern North America.  They winter in South America.  They prey on cold-blooded animals–large insects, frogs, lizards, and snakes.  Kites avoid freezing climates because their cold-blooded prey becomes inactive and unavailable.  Kites catch and eat cicadas and grasshoppers while they are flying…a kind of eat on the go attitude, like Americans eating hamburgers and French fries while they are driving their cars.

Swallow-tailed Kite Photo

Swallow-tailed kite.  I saw one of these once in Jenkins County, Georgia.  It was also soaring very high in the sky.

I’ve seen a swallow-tailed kite (Elanoides forfincatus) just once–in Jenkins County, Georgia.  They were formerly common, spending summers as far north as Minnesota.  Like Mississippi kites, they winter in South America.  Swallow-tailed kites were known for eating the insects and reptiles fleeing ahead of the annual fires that burned through pine savannahs.  Up until well into the 20th century, it was popular for people to shoot birds for the hell of it, and these callous hicks devastated swallow-tailed kite populations.  Swallow-tailed kites have been completely eliminated in North America outside of the south, and they are considered rare within this region.

Image of Snail Kite

The snail kite is a South American bird that ranges into south Florida.

The snail kite (Rostrahumus sociabilis) eats nothing but snails.  It lives in south Florida and central and South America and does not migrate.  In Florida the snail kite feeds upon apple snails.  It seizes the snail with its talons, then waits patiently for the snail’s head to emerge from the shell.  It quickly grabs the snail’s head with its beak and tears the body loose.  Snail kites are increasing in number, thanks to an abundance of invasive snails.  Snail kite populations have doubled in the 10 years since the Island apple snail, a South American native, escaped from aquariums.  In 2010 a scientist from the University of Florida published a stupid study claiming the introduction of the Island apple snail would cause the snail kite to become extinct in Florida within 30 years.  The author of this study suggested the kites would expend too much energy trying to exploit the larger snail.  However, snail kites in South America thrive on this snail, and the author of this  study saw his illogical conclusion debunked by the facts immediately. Most invasive species are considered destructive, but the introduction of the Island apple snail is a case of a beneficial invasion.  Besides snail kites, limpkins, another snail-eating bird, have increased in the past few years. Island apple snails even eat invasive hydrilla, a plant that clogs waterways all across the south.  Before the Island apple snail invasion, wildlife officials were afraid the Florida population of snail kite was headed for extirpation. 

adult

The white-tailed kite has a curious distribution, living in south Florida, south Texas, Mexico, Central America, and the Pacific coast.

White-tailed kites (Elanus leucaras) were absent from Florida between 1930-1985.  Hunters had eliminated this population.  But they have since recolonized Florida.  This kite has a curious distribution, living year round in south Florida, south Texas, Mexico, Central America, and the Pacific coast.  At some point during the Pleistocene, this bird probably had a continuous range.  The white-tailed kite is a species that requires prairie habitat.  During some climatic phases, a grassland corridor connected the eastern and western populations, but the area in between has since become forested.  In this respect it is similar to many other species such as the burrowing owl, scrub jay, brown-headed nuthatch, and diamondback rattlesnake that have separated eastern and western populations.

Kites are absent from the fossil record of southeastern North America, but undoubtedly they’ve lived here for millions of years.  Kites just happen to live in environments where they are not likely to become preserved.  They avoid caves and rarely die in a river–the 2 processes most likely to preserve them.  Fossil evidence of Mississippi kites has been found in northern Mexico.  Genetic evidence suggests different migratory populations of Mississippi kites diverged early during the Pleistocene and have not interbred since.  They’ve been spending summers in what’s now known as Georgia since before Homo sapiens existed as a species.

Horned Larks (Eremophila alpestris) were Likely an Abundant Bird during Ice Ages

June 29, 2014

Stadials, the coldest stages of Ice Ages, fostered an expansion of arid grassland habitat all across Eurasia, Beringia, and North America.  Droughts were frequent and low CO2 levels slowed plant growth.  Grass and conifers outcompeted broad-leafed trees in these conditions.  Arid environments favored grass-eating herbivores, and a variety of smaller animals that prefer wide open spaces.  The horned lark (Ermophila alpestris) is an example of a species that likely abounded in large numbers during stadials.  They inhabit environments consisting of sparse grass and bare ground.

Eremophila alpestris

Horned larks require a landscape consisting of bare ground and sparse grass. This type of environment was common during Ice Ages.

The horned lark nests on bare ground, laying their eggs next to a tuft of grass.  Like most ground-nesting birds, they will feign injury to lure a predator away, but they do wait longer than other species before taking this evasive action.  Today, horned larks breed and nest from northern Canada to as far south as Maryland.  They winter as far south as Georgia.  In the east they find the type of environment they like in salt marshes, beach dunes, and winter-fallow agricultural fields.  They are also known as shore larks.  During the Ice Ages much of their modern day American breeding grounds were under glacial ice, so it is likely they bred farther south in the steppe-like landscapes that occurred adjacent to the glacial boundary.

Pleistocene fossil evidence of horned larks is scant in the south, but specimens have been recovered from Cheek Bend Cave in middle Tennessee.  The lark specimens were found associated with bones of other northern bird species absent or uncommon in Tennessee today, including gray jays, boreal owls, saw-whet owls, purple finches, and prairie chickens.  Evidence of other bird species from the cave represent those still common in the region today–blue jay, red-bellied woodpecker, flicker, sparrows, meadowlark, and others.  (The eastern meadowlark (Sturnella magna) is not a true lark but instead is more closely related to blackbirds and starlings.  It too prefers open spaces.)  During winter horned larks join large nomadic flocks of sparrows, juncos, lapland longspurs, and snow buntings as they edge toward more southerly latitudes, though the larks are among the first to return north in the spring.  All of these birds were likely common on Ice Age plains.

Horned larks feed on insects and grass seeds, even foraging in horse manure for undigested seeds.   Horned larks and other birds scratching through mammoth and horse dung on frozen ground was probably a common sight during the Pleistocene. 

Chickens foraging for worms and undigested grain in horse manure.  Horned larks also like to forage through horse manure.  Horse manure would have been one of their important food sources during Ice Ages.  Just think about this next time you are sitting in front of a plate of fried chicken.

Horned larks belong to the Alaulidae family which includes 20 genera and 99 species, but they are the only true lark that managed to cross the Bering Landbridge.  All the other species are confined to Africa, Eurasia, and Australia.  The horned lark is a successful widespread species, living in both Eurasia, and North America.  At present they are still considered a common bird but in steep decline.  The conversion of open agricultural land to 2nd growth forest is eliminating their preferred habitat.

Can Conservatives get any more Heartless and Hateful?

June 25, 2014

I try to keep this blog focused on natural history, but some times I become aware of an issue that compels me to stand on my soap box and shout my outrage to the world.

I’ve read a couple of excellent books this summer–Tortilla Curtain by T.C. Boyle (my favorite writer), and Hammer of the Gods: The Led Zeppelin Saga by Stephen Davis.  The former is a novel that delves into the plight of undocumented immigrants seeking a better life in this country, and the latter is a biography of Led Zeppelin.  There are many fascinating details about history’s Number 1 rock band in Hammer of the Gods, but a few incidents  during the group’s concert tours of the south in 1969 seem eerily similar to how conservatives view undocumented immigrants.  Of course, southern kids loved Led Zeppelin and were always the band’s most boisterous fans, but the adults did not treat these hippies with southern hospitality.  Police threatened to physically brutalize the band, forcing Atlantic Records to hire their own thugs for protection.  Waitresses refused to serve them, and some  old southern fried fucks literally spit on the band members.  Hotel owners told the band members not to swim in the hotel pool because they didn’t want them to spread disease.  This last nugget of ignorance is what rings a bell.

Thousands of young children from Central America are escaping the rampant gang violence of their home countries by crossing the U.S./Mexican border.  U.S. border patrol agents are arresting them and confining them in small holding cells, even cages.  OUR TAX MONEY IS BEING SPENT ON PUTTING INNOCENT CHILDREN IN CAGES.  This is outrageous.  To justify this inhumane treatment, stupid redneck politicians claim these children might spread diseases.  These hypocritical politicians don’t give a shit about children getting sick.  Conservatives invariably fight to weaken or overturn environmental laws that prevent children from getting sick.  All of a sudden, they are concerned with childhood sickness?  Well, I say innoculate these children and send them to elementary school.  Put them up for adoption.  We should welcome them, not put them in cages like unwanted cats and dogs.

Brownsville US immigration

The United States can’t even spare a bed for these poor kids?  What a disgrace.

Conservatives claim the cost is too high to care for the children.  These are the same people who oppose abortion.  They favor forcing women to have unwanted children, yet are unwilling to pay for the care of children after they are born.  Conservatives should look at it this way: the Central American refugees are the replacements for all the aborted fetuses for which these jerks shed their crocodile tears.  We should adopt them, educate them, and let them be the future generation that supports us in our old age.  Opposition to accepting Central American refugees on the basis of economics is selfish and short-sighted.  It may cost more money to care for them now, but in the long run they could potentially pay us back with tax revenue from future labor.  Tax revenue from immigrants is the best hope of saving Social Security.

 

 

 

 

 

 

 

This is all the technology required to defeat the racist wall politicians had built along our border with Mexico.  There is no wall across our border with Canada because most Canadians are white.  The wall costs billions to maintain, yet does not keep a single person out.

The fence along the U.S./Mexican border is a racist symbol.  It prevents no one from crossing the border because it is easily defeated with a low tech ladder.  It costs billions of dollars to maintain–money that would be better spent on the care and education of the children who want to live here.

Conservatives refer to these children as “illegal aliens.”  This dehumanizes them and makes them sound as if they are monsters from outer space.  The other day, I listened to a local radio talk show host, Austin Rhodes, constantly refer to them as “illegal aliens” in one of his recent rants.  What really had him upset was the possibility that a child of an undocumented immigrant might get an education in a public school at taxpayer’s expense.  Really?  A kid getting an education is a catastrophe?  His racism was obvious.  According to his point of view, “illegal aliens” were like something subhuman who didn’t belong in school with real people.  He considered them all “bad guys.”  His sanitized racism appeals to the same types of old fart racists who spit on Led Zeppelin 45 years ago.

Austin Rhodes–Augusta, Georgia’s hate radio propagandist.  His sanitized racism still has a great deal of appeal in the south.  He referred to “illegal aliens” as “bad guys.”  His beef?  The children of undocumented adults might get a free education.  Heaven forbid!  What a catastrophe!  A child might get a free education.  This coward is a total shmuck who once threatened to send men to my house to beat me up.  Why?  Because I merely repeated a fact published in The Metro Spirit–a paper that publishes his asinine weekly column.  His former producer, Troy, the Apeman, Bradley warned me I should “pray I never meet him in the street.”  I guarantee Bradley would do nothing to me, if I met him on the street.  He is also a cowardly bully.  Bradley was too afraid to even take or return my phone call when I called him after his macho boast.

The Statue of Liberty - see all state symbols

Statue of Liberty

It is against American principles to keep poor oppressed people from living in this country.  We are a nation of immigrants.  Immigrants make the U.S.A. strong.  Undocumented immigrants are not all bad guys, as redneck conservative pundits claim.  They are simply seeking a better life for themselves and their families.  Conservatives need to pay a visit to the Statue of Liberty and read these words.

Give me your tired, your poor,
Your huddled masses yearning to breathe free,
The wretched refuse of your teeming shore.
Send these, the homeless, tempest-tossed, to me:
I lift my lamp beside the golden door.” –Emma Lazarus

Mr. Claw

June 24, 2014

Scientists classify the common house cat (Felis cattus) as a different species than the Old World wildcat (Felis sylvestris), but they are the same animal and readily interbreed in areas where they overlap.  Like the dog (Canis familiaris), I believe this species adopted humans, rather than vice-versa.  Humans have lived with cats for at least 9500 years–evidence of the oldest association between the 2 was excavated from an archaeological site in Cypress, Greece.  Cats first started living closely with humans when we began storing grain.  The grain attracted rodents, which in turn attracted cats.  Kittens, left unattended by their mothers, easily bond with humans who treat them with kindness.  The cat is an amazing intelligent survivor.  Fossils of F. sylvestris are often found in European caves, and this species has been in existence for over 2 million years.  Cats were able to live in environments with wolves, bears, lions, and mammoths; yet they were able to adapt to new environments shaped by humans, while the larger, fiercer beasts disappeared.

My favorite cat died about a year ago.  While she was alive, we never had mice in our house.  As soon as she died, mice and other small animals began to plague us.  Both the house mouse (Mus musculus) and the field mouse (Peromyscus sp.) invited themselves into our house.  I don’t appreciate mouse turds in my food supply, so I poison-baited our home–not the ideal solution because a poisoned mouse can go outside and get eaten by a bird of prey, thus killing the raptor too.  Usually, the poisoned mouse would emerge from hiding in a partially paralyzed state, and I would be forced to whack it with dress shoes that I refer to as my “mafia” shoes.

Frogs, like one of the 12 plagues of Egypt, also frequent our house.  Green frogs (Rana clamitans) burrow into the soil, find their way into our septic tank, and swim up the pipes to the toilet bowl.  I don’t mind the frogs, but my wife suffers from ranidophobia, or fear of frogs.  Small tree frogs (Hyla cinerea) often hang out by the living room window and croak so loudly that my wife can’t hear the television.  On several occasions my wife has interrupted me while I was enjoying my favorite video of a nude woman doing housework (http://www.dailymotion.com/video/xl5lms_cleaning-house-naked_redband), by ordering me to go outside and scare the frog away from the window.  She ignores my complaints about the futility of such an endeavor.

To keep my wet dreams from being ruined by my wife’s hysterics, I decided to tame a feral cat ranging in the woods behind my house.  I reasoned the mere presence of a cat in the immediate proximity of my house would keep the small pests at bay.

I started putting out food for the cat and gradually moved the feeding spot closer and closer to the house.  I sat outside on the back steps while he fed to get him used to my presence.  Some say feral cats never make good pets, but there is contradictory evidence of this on the web, so I viewed this as an experiment.  This required a great deal of patience.  To fight off boredom, I sat on the back steps, drank chilled white wine, and listened to rhythm and blues on my Sony Walkman.  I can get drunk and listen to music for hours without getting bored.  The cat saw me in my most relaxed state, and this seemed to relax the cat.  One day, I placed the cat food down, and the cat started circling me.  The circle kept getting smaller and smaller until he was rubbing against my legs.  And he let me pet him.  I thought this was great because I had earned the cat’s trust.

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Mr. Claw approaching me before he ever let me pet him.

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While I’m relaxing and drinking chilled wine on the back steps, Mr. Claw is getting relaxed enough to creep closer and closer.

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Now this once feral cat rubs up against my leg.  I’ve gained his trust, but now I don’t trust him.  The sneaky little fella likes to claw me, seemingly as a practical joke.  I also always wear shoes to protect my toes which have become irresistable targets.

Domestic cat, housecat (Felis catus), catching, eating Common house mouse (Mus musculus)

This is why I went to the effort to tame a feral cat.  After my beloved cat died last summer, we had mice in our house for the first time ever.  The smell of a cat alone is enough to keep mice away.

 

 

 

 

 

 

My wife is terrified of frogs.  This species, the green frog (Rana clamitans), often burrows into the soil and lives in our septic tank.  They occasionally swim up the pipe and into the toilet, causing my wife to have a freekout until I catch it and take it outdoors.  Maybe the cat will reduce the population of green frogs in our yard.

Green treefrog.jpg

Green tree frog (Hyla cinerea).  This species is common around my house.  Whenever they croak, my wife orders me to go outside, find the frog, and take it away.  How ridiculous!  This is annoying, especially when I’m in the middle of watching a stimulating video of a naked woman doing housework.  Cats like to eat little frogs like this.

A problem occurred when I was sitting on the back steps one evening while getting relaxed with wine and song.  The cat snuggled next to me, then suddenly clawed my arm and retreated a short distance.  It occurred to me that the cat was playing because my late aunt and uncle had a Siamese cat that engaged in similar behavior but with the neighbor’s dog.  Their neighbor had a German shepherd kept chained in the backyard.  My uncle’s cat would slowly creep toward the dog which would go crazy barking and pulling on the chain.  The cat would smack the dog on the nose and run away–obviously teasing the hell out of it.  Could this cat be teasing me?  In any case, this cat earned the name, Mr. Claw.  He later laid down in front of me with his paw pointed toward me–claws unsheathed!

Since then, this sneaky cat has clawed my toe and my ankle, and I no longer trust him.  A cat expert suggested playing with the cat to channel its aggressiveness, but Mr. Claw shows no interest in playing with conventional cat toys.  He prefers the claw and run tease.  The difference between Mr. Claw and my old deceased cat is like the cliche` night and day.  Mr. Claw is aggressive, unpredictable, and sneaky.  My old cat, Lone Ranger, was always gentle and docile.  Mr. Claw probably needs to be fixed, but I don’t want to pay for that.  Removing a cat’s testicles seems like the equivalent of giving a human a lobotomy.  The experiment continues…

Mt. Mitchell and Chimney Rock State Parks

June 20, 2014

For our family vacation this year, I wanted to visit St. Simon’s Island, so I could walk through an old growth live oak forest and also hunt for fossils in the lagoon behind the island.  However, my wife objected to the heat and expressed her desire to seek relief in the Blue Ridge Mountains.  We have a successful marriage, meaning we compromised by choosing her destination.

We went to Mount Mitchell State Park located 35 miles north of Asheville, North Carolina.  To get there, it’s necessary to travel along the Blue Ridge Parkway.  I was looking forward to this route but was unimpressed and very disappointed with the Blue Ridge Parkway National Park.  It’s simply a busy road through the woods, and I can’t believe this sorry stretch is part of the national park service.  There were gangs of motorcyclists and inconsiderate bicycle riders and even an 18-wheeled truck.  The road is narrow and winding with a speed limit of 35 mph.  The bicycle riders act as if they own the road–not a single one of those lazy assholes pulled off the road to let us pass.  The entire parkway is a no passing zone and around many of the bends visibility is too poor to safely pass the bicycle riding jerks.  The only wildlife I saw on the parkway was a woodchuck.  I didn’t even see a single bird or gray squirrel.  By the time I reached the road that leads to Mount Mitchell, I was in a foul mood.  My aggravation increased because I hated the endless, climbing, winding road that led to the top.

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Note the line of dead trees halfway up this mountain.  This forest is dying.

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See how open the terrain is?  If there were any large mammals in the park, they would be visible.  The population of large mammals in Mount Mitchell State Park is zero.  There aren’t even any white tail deer.

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At 6578 feet Mount Mitchell is the highest elevated point east of the Mississippi.  Nevertheless, a visit here is not recommended.

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Path through Craggy Gardens located off the Blue Ridge Parkway.  It’s a thicket of catawba rhododendron and stunted birch trees.  I saw a yellow-throated warbler here but little else in the way of wildlife.

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Note how the roots of this birch tree are growing over a boulder.

The sign welcoming us to Mount Mitchell stated that it is a “World Biosphere Preserve.”  This is a joke.  The trees are all dead or dying and the whole park is nearly devoid of wildlife.  Woolly adelgids, an invasive insect, have killed all of the Frasier firs, and acid rain is in the process of killing the red spruce.  Mount Mitchell used to host an interesting boreal forest with flora and fauna more commonly found in the Canadian life zones.  Now it is practically dead.  The landscape is open so from the top of the mountain, it’s possible to see every large mammal for miles.  I did not see a single deer, elk, wild boar, or black bear.  The population of large mammals in Mount Mitchell State Park, aside from Homo sapiens, is zero.  There are supposed to be red squirrels here, but I did not see a single squirrel’s nest, let alone a squirrel.  Bird populations are also very low.  I saw a few sparrows and swallows and a gray bird that I could not identify despite combing through my field guides for 90 minutes when I returned home.

A restaurant exists on Mount Mitchell.  They charge extra money for the view.  For example they serve a hotdog for $9.  Mount Mitchell totally sucks.

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Menu from the Mount Mitchell State Park restaurant.  9 bucks for a hotdog.  They suck.

 Chimney Rock State Park

The road to Chimney Rock State Park located about 30 miles south of Asheville doesn’t suck as bad as the Blue Ridge Parkway but I saw even less wildlife here.  The view of the cliffs is spectacular. 

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View of Chimney Rock cliffs.

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This tunnel was bored through 500 million year Cambrian-aged rock.  It leads to an elevator that ascends 26 stories in 30 seconds to the top of Chimney Rock.

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View of Lake Lure from the top of Chimney Rock.

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View of a cliff opposite Chimney Rock.

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Chimney Rock.  To be honest, as soon as I was on top of Chimney Rock, I wanted to go back down to earth.  I’m not afraid of heights but they make me feel uneasy.

The cliffs here reminded me of an article I wrote about a year ago. http://markgelbart.wordpress.com/2013/05/19/piedmont-cliff-ecology/  Supposedly, peregrine falcons nest on the cliffs but the only bird I saw was a black vulture.  Surprisingly large birch and hickories grow on the rocky cliff faces along with many cedar trees.

Lake Lure

My daughter and I went for a walk around Lake Lure, a manmade body of water in the valley between the cliffs of Chimney Rock.  It was hot, and we were delighted to find a public swimming beach here.  The cool swim in the lake salvaged my mood.

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View of cliffs from Lake Lure.

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There’s a belted kingfisher nest in the mud bank on the shore of Lake Lure.  I saw more wildlife in the Lake Lure city park than on the Blue Ridge Parkway, Mt. Mitchell, and Chimney Rock combined.

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Ah Hah!  There is a public swimming beach here.  This swim after a hot walk was the highlight of my vacation.  Note all the Canadian geese.  I told my daughter to make sure not to swallow the water.  With all the goose fecal matter, it’s probably contaminated with E. coli.

The restaurants in Asheville serve “home cooked” southern fare.  The food may be good but it is not as good as my own cooking.  The Moose Cafe near the Asheville Farmer’s Market serves excellent biscuits and corn bread but their entree’s were overseasoned with salt while their sides were underseasoned.  The local cuisine is nothing to get really excited about.

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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