Archive for October, 2011

The Chernobyl Exclusion Zone

October 28, 2011

Wilderness is retaking the Chernobyl Exclusion Zone, a restricted area in the Ukraine and Belarussia.  A nuclear accident here in 1986 turned this region into the greatest wildlife refuge in Europe.

Because time travel to Pleistocene Georgia is technically impossible, I suppose, if I really insisted on living in a real wilderness, I could bribe a Russian official to let me live with the few peasant squatters who still inhabit the Chernobyl Exclusion Zone.  Officially, no one is supposed to reside here, but the Russian government lets a small group of people enjoy living a pre-industrial lifestyle here.  Before the 1986 nuclear meltdown, Pripyat, formerly the largest urban center in the zone, was a thriving industrial city of 50,000.  Chernobyl originated as a port town run by Jewish merchants, but the Soviet government chose the site for the construction of nuclear reactors, and nearby Pripyat became a fast growing city, a home for the workers.  The area around the city consisted mainly of collectivized farms, and agricultural land was expanding because engineers were draining the vast wetlands adjacent to the major river.

Soviet engineering incompetence is legendary.  Here’s a famous Russian joke that illustrates this ineptness perfectly.

How do you sink a Russian submarine?

Put it in the water.

Ironically, a safety test caused the Chernobyl meltdown.  The safety test malfunction, then human error and design flaws compounded the disaster.  The Chernobyl nuclear reactor was the only one in the world constructed with no containment room–that alone would have been enough to prevent the catastrophe.  The Soviet government evacuated everyone living in Pripyat and all the surrounding towns and farmland.  Most of the residents thought the evacuation was temporary, and they left most of their stuff behind.  Today, looters scavenge this radioactive contraband.  Nuclear fallout spread throughout Europe, and contamination is still a problem as far away as Great Britain in some localized areas where nuclear rain happened to fall.

The Soviet Union established the Chernobyl Exclusion Zone encompassing 1660 square miles where no one is officially allowed to reside with the exception of 2000 workers who live in shifts in Pripyat.  It’s still necessary to maintain the reactor even though it’s useless for energy production.  Workers suffer an elevated risk of cancer.  They’re frequently given physical examinations, and if cancer is diagnosed, they’re fired.  Since the Soviet Union collapsed, Belarussia and the Ukraine have split responsibilty for the zone.

The infamous red forest within the CEZ.  Radiation turned the pine trees red in the forest immediately adjacent to the nuclear reactors.

The CEZ rapidly converted back to a wilderness that is far more impressive and interesting than any of America’s overcrowded National Parks.  A forest composed of pine, oak, birch, aspen, and chestnut grows on abandoned farmland and even within  city limits.  Beavers tunneled through dikes and built dams on manmade canals, restoring the original grassy and woody marshes, peat bogs, and wet meadows.  Unchecked forest fires and storm damage diversifies habitats.  Overgrown fruit orchards provide abundant food for wildlife.  Radiation poisoning is only visually evident in a small stretch of land adjacent to the nuclear plant known infamously as the “red forest.”  Radiation turned the green pine trees red.  Workers bulldozed and buried much of this contaminated environment, but pine trees resprouted, and they’re still red and in some cases stunted.  The return of wildlife has been spectacular.  Apparently for wildlife, the presence of humans is worse than radiation poisoning.

Wild boar romping in the CEZ.

5000 wild boar roam the CEZ, making them the most common ungulate.  The males are huge, chest high, beasts weighing up to 500 pounds, and they are fierce and dangerous to humans.  Elk (called red deer in Europe), moose (called elk in Europe), and roe deer are also common.  European bison and Przewalski’s horse have been re-introduced, giving the zone a real Pleistocene feel.

Check out this youtube video of wild horse galloping across the plains of the CEZ.  Looks like a scene from the Pleistocene.  The herd should number 200, but instead is just 60 due to poaching.  The economy in this part of the world must be pretty bad, if people are desperate enough to eat radioactive horse meat.

Rumors among the locals suggested a wolf population approaching 300, but a scientist studied the wolves here and estimates the population to be closer to 120–still impressive.  One incident demonstrates how wild the CEZ has become.  A scientist found himself surrounded by a wolf pack, and he had to shoot every one of them to escape.

Other rare European mammals have returned, including brown bears, lynx, otters, and beaver.  The population of badgers, rabbits, hares, and squirrels is on the rise.

The Pripyat River, 10 miles wide in some places, has always been a destination for birdlife.  Birds like to nest on the numerous grassy and woody islands and swamps in this maze of wetlands.  Over 120 bird species utilize the CEZ for seasonal or year round residence, and now rare species are increasing in number.  White-tailed eagles, great spotted eagles, Eurasian eagle-owls, cranes, marsh sandpipers, and golden-eyed ducks; some of these species completely extirpated in most of Europe; exist here in healthy numbers.  White storks, which prefer the company of man, have left the area, but black storks, denizens of deep wilderness, are now nesting here.

Catfish and carp swimming in the canals adjacent to the reactor are growing huge–up to 80 pounds.  The fish live a long time when there is no danger from human fishermen, and once they reach a certain size, they’re too big for most common natural predators.  White-tailed eagles do prey on surprisingly large fish here.  The PBS nature series, fittingly called Nature, recently had an episode about the CEZ entitled “Radioactive Wolves,” that showed the remains of several 40 pound carp.  Eagles had dragged the heavy fish out of the water and consumed them.  However, the fish bones were too radioactive for humans to even handle.  Fish from the Pripyat River are safe for humans to eat  because the flowing water flushed the radioactivity downstream.

Some scientists dispute the notion that the CEZ is a wilderness paradise.  They note the high rates of mutation, such as albinism.  Radiation increases the rate of mutation, and most mutations are detrimental to a species survival.  They’ve determined the area immediately around the reactors acts as a population sink.  They studied barn swallows and discovered the favorable habitat attracts lots of birds, but fewer survive here due to the radiation.  Other scientists reject their findings.  Most animals can endure more radiation than humans and because they don’t live as long, they have less of a chance to develope cancer.  One species of mouse has even evolved resistance to radiation.

I think the U.S. government made a mistake by de- emphasizing the development of nuclear power.  The risk of radiation contamination is small and is not nearly as bad as coal and oil pollution.  Mountain top removal mining permanently destroys the land, mercury poisons our water, coal smoke ruins the air, and oil spills devastate the land and the sea.  Clean alternatives will always be inadequate.  Wind doesn’t work on calm days; solar doesn’t work at night and on rainy days.  Every source of energy has its drawbacks, but nuclear power has the least.  Anyway, what’s the worse thing that can happen?  A meltdown could occur, forcing humans to abandon a sizeable territory back to nature.  What’s wrong with that?


The Pleistocene Vampire Bat (Desmodus stocki)

October 24, 2011

A drawing of the type specimen’s skull and fang.  Desmodus stocki was 20% larger than the still extant common vampire bat (Desmodus rotundus), and it was probably adapted to a cooler climate.

This creepy creature seems an appropriate enough subject for Halloween week.  It’s perhaps the most surprising and strangest animal included in the list of species that occurred in southeastern North America during the Pleistocene.  Fossil evidence is scant but sufficient to suggest it lived throughout the entire region.

Photo of a caver inside New Trout Cave, West Virginia.  Pleistocene vampire bat fossils were found here.

Fossil bones of the Pleistocene vampire bat have been found in Cuba, Mexico, Florida, Texas, Arizona, northern California, and West Virginia.  The latter two sites are about the same latitude.   The fossils from New Trout Cave, West Virginia date to 29,000 BP, a time of a weak interstadial preceding the Last Glacial Maximum.  Modern vampire bat species can’t survive temperatures that fall below 50 degrees Fahrenheit.  Some scientists think winter climates during the Ice Ages were milder south of the ice sheet than those of today, explaining why vampire bats were able to live this far north, but I don’t agree.  The species of plants inhabiting the south then were temperate and in some areas even boreal.  29,000 years ago, the Laurentide Glacier was very close to New Trout Cave, so winter temperatures must have consistently been below freezing here during winter.  Pleistocene vampire bats were probably able to survive cooler temperatures than their modern cousins.

Pleistocene vampire bats enjoyed an abundant supply of food, likely gorging on the blood of giant ground sloths, mammoths, mastodons, bison, horses, llamas, peccaries, bears, big cats, wolves, and maybe even paleo-Indians.  There’s no direct evidence proving they fed upon the blood of these victims, but I think it’s a safe assumption they did.  Their bones have been found associated with giant sloth remains, though this doesn’t really count as proof.  They did occur on islands where the only large mammals were dwarf ground sloths, making it certain they must have plagued the latter.  Vampire bats require lots of blood (their sole source of nourishment) and will die, if denied food for more than two days.  To survive a shortage of food, they share blood by regurgitating it to each other.

I think the reason Desmodus stocki is not more commonly found in the fossil record is because they usually roosted in hollow trees where their remains would decay into nothingness along with the wood and leaf litter of the forest.  The extinction of Desmodus stocki paralleled the extinction of the megafauna.  They were a commensal species that couldn’t survive the loss of such an abundant source of blood.  A population of Pleistocene vampire bats persisted on San Miguel Island off the coast of California until  3000 BP, indicating pygmy mammoths inhabited the island til then.

Best photo of a common vampire bat found on google images.

Today, there are at least three kinds of vampire bats and all inhabit the tropics of South and Central America.  The white winged (Dianus youngi) and the hairy legged (Dyphylla ecaudata) both feed upon the blood of birds.  The common (Desmodus rotundus) feeds upon the blood of mammals, and its numbers have skyrocketed since the introduction of livestock to South America.  Diseases carried by vampire bats cause the deaths of hundreds of thousands of cattle and horses every year.  The same must have been true of the megafauna during the Pleistocene.  The rate of rabies must have been high in that primeval world.  However, it’s unlikely this contributed to any extinctions because vampire bats and megafauna co-existed for millions of years.

A fourth species, the giant vampire bat (Desmodus draculae), may still be extant.  Scientists dated a fang of this species found in Argentina to be just 300 years old.  It’s the only bat fossil of any kind found in Argentina.  Other fossils of this species have been found in Brazil and Venezuala and date to the Pleistocene.  Cattlemen occasionally report seeing exceptionally large vampire bats feeding on their stock.  Cryptozoologists are on the lookout for it.  In this case they may be chasing a real species, not an imaginary one.

Vampire bats evolved during the Miocene, at least 8 million years ago, probably from bats that specialized in eating either ticks or maggots living on open wounds on large mammals, much like African oxpecker birds do today.  Evolving from eating maggots and/or ticks to consuming blood required only a few inherited mutations.

The legend of the vampire predates the European discovery of the vampire bat by at least 500 years.  The English word, vampire, was derived from the German vampir in 1734, but the German word can be traced back to the Russian word, uper which dates to 1047.  Ancient Babylonian legends include tales of blood-sucking ghosts, predating the origin of the Russian word.  Europeans didn’t discover the existence of vampire bats until 1526 when an early Spanish explorer awoke and found one sucking blood from his toes.

Of Lycanthropy and Dire Wolves (Canis dirus)

October 19, 2011

The fictional depiction of lycanthropic transformation is reminiscent of an oversimplified depiction of evolution. Although it seems a bizarre twist of logic, evolutionary science does support the existence of an animal that was part man and part wolf.

Man is a beast.  I think the ancient superstitious legend of the werewolf originates from a fear of ourselves or at least a fear of feral individuals within our society.  People with various mental illnesses don’t follow the rules of civilization and behave as if they were wild animals.  In modern cinema and literature the transformation of man to wolf appears as a kind of reverse evolution, depicting the man de-evolving into the most feared animal in medieval Europe–the wolf.  Of course, this doesn’t parallel the reality of evolution.  Evolution doesn’t reverse course, though occasionally retro mutations take place that begin new lines of progression.  But if evolution could reverse course in a linear regression, a man transforming back into beast would become apelike rather than as a canid/human hybrid.  On the tree of evolution primates are far removed from canids.  Despite the vast distance between the two on the evolutionary timescale, primates and canids do share a common ancestor.  Both man and wolf can trace their evolutionary lines back to a single unknown species of insectivore that diverged into two species early in the Eocene 55 million years ago, or probably earlier.  The split may have occurred as early as the Paleoecene or the Cretaceous.  When dinosaurs walked the earth what was to become man and wolf was the same animal.  According to what we know of evolution, werewolves were real and may have lived with the dinosaurs.  But they were nothing like the monsters depicted in fiction.  Instead, they were shrew-like animals, something a modern day house cat could toy with.

This is not a man wearing a werewolf mask.  He has a rare condition known as hypertrichosis.

The legend of lycanthropy may predate written language.  Both the Greeks and the Romans believed in the existence of men who could temporarily transform themselves into wolves.  The word, lycanthrope, itself is Greek: lycaos means wolf, anthrope means man.  A belief in the existence wolf men persisted in medieval Europe.  Today, we can be certain the legend was based on a number of strange factors that modern science can explain.  Then as now, serial killers occasionally terrorized society. Instead of blaming a deranged man for mutilations and murders, authorities scapegoated wolves despite conflicting evidence implicating a human.  They couldn’t comprehend that a man could be so vicious.  Diseases such as rabies and and the disorder of hypertrichosis compounded the confusion because symptoms of these conditions partly mimic the legend.  The Age of Reason ended the widespread belief in the existence of werewolves, but the legend lives on as a popular monster of horror fiction.

Here’s a skull comparison between a dire wolf and a timber wolf.  I found this photo on another wordpress blog. 

When paleo-indians encountered dire wolves they were forced to deal with a real monster.  Unlike timber wolves (Canis lupus) which originally evolved in Eurasia, dire wolves evolved in America where the large pack-hunting canids never learned to respect or fear man.  Studies of the fossil record suggest dire wolves appeared suddenly about 200,000 years BP.  They replaced Armbruster’s wolf which had been the dominant canid in America for over a million years.   It’s unclear whether dire wolves evolved from Armbruster’s wolf or another canid (C. nehringi), a little known extinct canid that inhabited South America.  Dire wolves ranged from coast to coast and from what’s now southern Canada to Peru.  They’re very common in the fossil record, suggesting they were the most abundant large predator on the continent.  In the northern parts of their range they co-existed with timber wolves.  In the southeast they co-existed with red wolves (C. rufus) and coyotes (C. latrans). 

I didn’t include an illustration of a dire wolf because at first glance, they would’ve probably looked just like a modern day timber wolf.  There were some subtle anatomical differences.  Dire wolves had a broader head, larger teeth, stronger jaws, and shorter but stouter legs.  On average they were significantly larger than timber wolves.  The average weight of an adult timber wolf is ~80 pounds.  The average weight of an adult western dire wolf was  ~120 pounds; the average of an adult eastern dire wolf was ~140 pounds.  Scientists noted a difference in size between eastern and western dire wolf fossils.  Eastern dire wolves also had longer legs than their western cousins.  Thousands of dire wolf skulls have been recovered from the La Brea tarpits in California.  Coincidentally, one of the few dire wolf skulls found in South Carolina was larger than all but one of the California skulls.  Though timber wolves average 80 pounds, some individuals do reach 160 pounds.  That suggests a really large dire wolf would’ve approached 200 pounds.  White tail deer are not large enough to sustain a pack of wolves consisting of individuals of this size.  Dire wolves required abundant bison, horses, llamas, and juvenile mammoths and mastodons.  Man and the extinction of the megafauna caused the downfall of the dire wolf.  

Interestingly, the appearance of dire wolves coincides with the evolution of the larger Smildon fatalis from the smaller Smilodon gracilis, indicating an arms race of sorts between the two.


A comment on last week’s nudie photo

I thought the hypothesis I discussed in my last week’s blog entry would be of interest to members of the fossil forum, so I posted a thread about it.  I wanted to kick my hypothesis around and see what they thought of it.  A moderator pulled the thread because my blog, which I linked, had a photo of a naked woman.  He remarked that they like to keep the fossil forum “kid friendly.”  Of course, they have the right to control the comment on their website, just as I have the right to moderate my own.  But I don’t agree with the value system behind their reasoning.

The thread was pulled on a Saturday.  It occurred to me that violent college football was on television all day.  Football is a sport where men break each other’s bones on a regular basis, and a significant risk of inflicting permanent brain damage is high.  Society is ok with exposing kids to violence, but the image of a beautiful naked woman is somehow not “kid friendly.”  Violence is good; sex is bad.  I don’t get it.

A few years ago, people were freaking out because of Janet Jackson’s wardrobe malfunction.  For some reason parents were furious because children might have accidentally viewed a woman’s breast.  The same thing happened once when an intro for Monday Night Football included a sexy seductive woman.  Yet, they’re ok with big defensive lineman clobbering quarterbacks in a game.

I’m a big Georgia Bulldog fan.  David Pollack was one of my favorite players, but I found his religious values somewhat twisted.  He refused to participate in his selection as  a Playboy all-American because of his religious beliefs.  He wears a wristband with the quote of “What would Jesus do?”  Well, I’m pretty sure Jesus wouldn’t knock the shit out of a quarterback.

Our society considers it acceptable to expose children to violence as entertainment but rejects exposing them to images of naked women.  Our society has a twisted value system that teaches kids violence is good but sexuality is dirty and bad.  I don’t agree with the notion that viewing images of naked women is in any way harmful to children.

The Venus of Willendorf: Pleistocene Sex Object?

October 14, 2011

Photo of the Venus of Willendorf from google images. This ancient figurine is small enough to fit in the human hand.  The genital area was originally covered in red ochre.

This masterpiece dates to between 24,000 and 22,000 BP and was found in a loess deposit near the Danube River, Austria in 1908.  Over a dozen figurines similar to the Venus of Willendorf have been discovered in central Europe and most date to this time period.  The existence of these figurines inspires two questions that archaeologists may never be able to answer.  What did the figures symbolize, and how did the models get so fat in a pre-agricultural society?

During this time period there was no written language.  Writing and numbers weren’t invented until agriculture became well developed, and the political powers needed a method of dividing the harvest equitably or, more often,  in favor of the elite.  Without a written record we can only guess what the figurines meant.  There are several lines of conjecture.  Some think the figurines symbolize a queen-based matriarchal society.  Others believe they symbolize mother earth.  A third possibility is that they represent charms for women hoping to get pregnant.  I reject all of these ideas.  I doubt there was a society then organized enough to consistently be matriarchal.  The myth of a mother earth probably didn’t exist until the ancient Greeks began to form a civilization.  And I don’t think primitive women were eager to become pregnant then because there was a high rate of deaths and no relief from the pain.  Instead, I believe they represent sex objects, probably even sex slaves.  I’ll explain this further in the next paragraph because it also involves care and feeding.

Archaeologists are certain the Venus of Willendorf was sculpted using a real model.  It’s anatomically accurate and only a person familiar with a real fat woman would be capable of sculpting such a figurine.  This is astonishing.  22,000 years ago, all humans on earth were hunter/gatherers.  Most of them, especially the women must have been scrawny.  A few tribes in Africa and South America still live as hunter/gatherers, and none of their women come close to approaching the corpulence of the Venus of Willendorf.  Ice Age people in central Europe lived on a diet of mostly lean wild game, fish, and wild plant foods.  It must have taken a considerable effort for a group of men to fatten a woman to this size before bread, cakes, and other high carbohydrate foods were invented.  I propose that the men in a tribe chose their best looking or most congenial woman and kept her penned in a dwelling, perhaps one of the houses they made from mammoth bones or more commonly wood.  Here, she lived a sedentary lifestyle, while the men hunted and gathered for her, and they gave her the choicest most fattening foods available to them–the brains, liver, and marrow of large mammals; bear lard; whole salmon and its caviar; sacks of hazlenuts; wild honey; etc.  The men shared her–some stayed with her, while the others searched for food and vice versa.  They took turns searching for the choicest foods.  In exchange for bringing her food she gave them sex.  The men, whose turn it was to look for food, carried the figurine of her with them and used it to fantasize and maturbate around the campfire.  If they met strange men from other tribes, they showed them the figurine and promised to share her in exchange for quality food.   The more men belonging to this club, the fatter the woman would get. 

This arrangement gave this culture a survival advantage, at least for awhile.  A well nourished woman would be more likely to survive childbirth and bear healthy children.  There’s a probability that the men kept her lactating as well and could nurse milk for extra nutrition.  Perhaps that’s a contributing factor of why most Europeans evolved the capacity to digest milk as adults.  Eventually, this culture disappeared but it may be a precursor to the modern cultural expectation that men should be the family provider.

A modern day Venus.  A fat tummy is no longer considered attractive by most men but the big boobs and buttocks are still popular.  Photo from google images.

The Beauty of Pleistocene Swans (Cygnus buccinator)

October 10, 2011

Photo from google images of a trumpetor swan.

No animal symbolizes the beauty of the Pleistocene more than the trumpetor swan (Cygnus buccinator).  I suppose we can consider it a stroke of good fortune that this species didn’t become extinct with the spectacular megafauna of that bygone era.  Contemporary efforts to protect the bird and help re-expand its range have even been moderately successful.

Modern range map of the trumpetor swan.  It occurred as far south as South Carolina during colonial times.  During the Pleistocene there was likely a sizeable population of this species in the southeast where it is completely absent today.  Fossils of this species have been recovered from northern Alabama and Florida.  Overhunting by men extirpated this species from much of its former range.

Before European settlement of North America trumpetor swans were more common and widespread, migrating as far south as South Carolina during severe winters.  But during the Pleistocene they ranged even further south.  Bell Cave in northern Alabama and several sites in Florida have yielded fossils of this bird.  Ice Ages provided ideal habitat for this species.

Audubon mentions that trumpetor swans prefer a moderate climate.  Ice Age summers in the south were generally cooler and winters were still moderate, so swans would have had a favorable climate in this region then.  It seems likely that Pleistocene trumpetor swans bred and nested on the abundant glacial lakes near the boundaries of the great ice sheets. Then during winter they didn’t have far to migrate because the distance between glacial lakes and favorable wintering habitat in the south was much less than the distances they have to travel today.  Perhaps a segment of the population remained and nested in the south year round, much like modern day sandhill cranes of which some migrate and some are permanent residents.

Map of the Laurentide glacier.   During the LGM swans didn’t have far to migrate between summer nesting grounds near glacial lakes and winter habitat in the south.  Some segments of the population probably lived year round in the south.

Swans inhabit ponds and small lakes with aquatic plants growing on the bottom upon which they feed. Extensive beaver ponds and marshes, and oxbow lakes were the kinds of abundant habitat in the south available to the big birds then.  Swans nest and take cover on beaver dams, muskrat lodges, and islands where they’re relatively safe from mammalian predators. If hungry enough, mammalian carnivores will expend the energy to swim and search for food in wetlands, but it’s not their first choice when looking for an easy meal.  During stadials, islands on braided rivers were common, giving swans lots of favorable habitat.  This wouldn’t have kept swans safe from eagles, however.

Photo from google images of a bald eagle killing a swan.  Eagles of several kinds were common during the Pleistocene.

Grinnell’s crested eagles, golden eagles, and bald eagles were capable of hunting and killing swans during the Pleistocene.  But swan defense mechanisms were adequate enough to maintain substantial populations.  Swans weigh up to 30 pounds and a blow from their wing is powerful enough to break human bone.   They can also flee by submerging and swimming for some distance.  They’re most vulnerable to eagles and human hunters when in flight.

Swans have an interesting method of feeding.  While they swim on the water, they lower their long necks to reach the aquatic plants growing on the bottom.  Because they have longer necks than geese, they can outcompete them for food by eliminating all the fodder within a goose’s reach.  Swans also graze grass on land; and they eat snails, reptiles, and small mammals.

Pleistocene Prairie Chicken (Tympanuchus cupido) Fossils Found in Southern States

October 5, 2011

Photo of greater prairie chicken from google images.

Youtube video of greater prairie chickens drumming on leks to attract mates.

During the Pleistocene prairie chickens were a common bird, at least locally, in southeastern North America.  Fossils of this species have been recovered from sites in Tennessee, Georgia, Alabama, and Florida.  All of these fossils come from cave deposits where hawks and owls originally dropped their remains while feeding.  Bones from at least 4 individual prairie chickens were excavated from Kingston Saltpeter Cave in Bartow County, Georgia, suggesting they were more than just an occasional species, even though most of the bird fossils found there were from woodland species.

There were 3 subspecies of prairie chicken: the greater prairie chicken (T. cupido americanus) which formerly ranged thoughout the tall grass prairie region but has been declining; the endangered Attwater’s (T. cupido attwateri) which lives on the coastal prairies of Texas; and the extinct heath hen (T. Cupido cupido) which lived along the coast of New England.

Specimen of a heath hen. I think heath hens should be considered a different species from the greater prairie chicken based on habitat preference and a DNA study.  Heath hens differed slightly in appearance as well.  They have a more reddish hue, their tarsi are shorter, and they have 5 neck feathers instead of 10.

The difference in habitat preference between greater prairie chickens and heath hens is astonishing.  Despite being considered the same species, their habitat preferences were the exact opposite.  Prairie chickens need completely open grassland of at least 130 acres in extent or their populations will decline.  They can’t even tolerate forest edges.  Trees provide perching platforms for predatory raptors that decimate them.  By contrast heath hens inhabited impenetrable coastal thickets consisting of bayberry, blueberry, beach plum, pine, and shrub oak.   A DNA test shows there were 6 degrees of mutational differences  between prairie chickens and heath hens.  The authors of this paper (referenced below) were hesitant to suggest a new species because their study was based on specimens of the last individuals which were residents of the heath hen’s final refuge on Martha’s Vinyard.  No museum specimens of mainland heath hens exist.  Therefore, the widely differing genetic lineage might be just for the final isolated island population.

Market hunters destroyed heath hen populations on the mainland (reportedly they were tasty).  In a desperate attempt to bolster the final intact population of heath hens on Martha’s vinyard, naturalists introduced greater prairie chickens, but their efforts failed because the introduced birds couldn’t adapt to the different environent.  A fire in 1916 followed by heavy raptor predation and introduced diseases wiped them out by 1932. The Nature Conservancy is considering introducing prairie chickens to Martha’s Vinyard, but this plan should be abandoned–I think it’s doomed to failure because they’re not the same species.

I believe heath hens were genetically isolated from greater prairie chicken populations during the LGM.  A lobe of the Laurentide glacier separated the two populations.  Heath hens survived on the unglaciated continental shelf and islands along the New England coast and gradually adapted to thickets rather than grasslands in a process that took thousands of years.  There’s not much chance of greater prairie chickens being able to adapt to coastal thickets in just one generation.

Pleistocene prairie chicken populations in southeastern North America were likely more adapted to grasslands, like modern day greater prairie chickens, though they may have had more variation in habitat tolerance than their modern descendents because the overall population of the species was so widespread.  Grasslands were common in the south during Ice Ages, especially during cold arid stadials, and this habitat persisted during interstadials as well.  Though most of the fossils of bird species found in Georgia, Alabama, and Tennessee are from woodland species, prairie chickens are not the sole grassland species.  Fossils of upland sandpipers (Bartramia longicauda) and magpies (Pica pica) also consistently are represented in avian fossil records here, indicating the presence of extensive grasslands.

I came across a study of presettlement land surveys in southeastern Arkansas that shows how grassland habitat large enough to support stable prairie chicken populations could have been distrbuted in the mostly woodland dominated environments of north Georgia and Alabama during the Pleistocene.

Map of Ashley County based on surveyor information from the below referenced paper written by Don Bragg.  There were sizeable prairies within the mostly wooded landscape.

Before European settlement the Ashley County region of Arkansas consisted mostly of upland pine-hardwood forests and bottomland swamps.  However, there were extensive tracts of grasslands large enough for early surveyors to name.  As I noted earlier, studies show that prairie chickens require treeless grasslands of at least 130 acres or their populations will decline until they eventually are extirpated.  Surveyors found at least 5 prairies in Ashley County.  Pine Prairie was 6800 acres, Twin Prairie was 2300 acres, Fountain Prairie was 2000 acres, Brushy Prairie was 500 acres, and Little Prairie was 300 acres.  A map of what’s now Bartow County, where prairie chicken fossils were found, would have had a similar distribution of prairies in a landscape composed more of mixed pine and oak forests and riverine woods.

In Ashley County (and probably the Pleistocene upper south) there were 4 different kinds of prairies.  Upland prairies are created and maintained by frequent fire and megafauna grazing.  Bottomland prairies form from a combination of fire and flood, both of which kill trees.  Alkaline prairies are areas with poor drainage.  As rainwater evaporates rather than draining away, basal salts accumulate, making it difficult for trees to grow, so grass dominates.  These are also known as lick prairies because ungulates are attacted to the accumulation of mineral salts.  Oak barrens are like savannahs with widely spaced post oaks and shortleaf pines.  Light fires kill all but the most fire tolerant species of trees here.  A rare unusual type of barren–hickory/dogwood–occurs in this region too.

Surveyors mapped the Ashley County district between 1818-1855.  They didn’t count every single tree, so studies based on their data are inexact but give good general information.  They marked plats of land by choosing and marking several witness trees on each plat.  The kinds of trees they marked are preserved in written records.  Black oak made up 18%, pine 17%, post oak 11%, white oak 9%, hickory 7%, sweetgum 7%, and all other species 31%.  An exact list can be found on a link to the paper in the references below.  The surveyors didn’t use the largest specimens as “witness” trees, but they still recorded some large trees, including a 12 foot in diameter cypress, and 6 foot in diameter black oak and loblolly pine.  Wild peach and apple trees occurred near abandoned Indian villages.

Ashley County surveyors noted a number of interesting landsapes created by disturbances which I summarize below.

Map of windthrows in presettlement Ashley County from the below referenced paper.  Some of the tracts were obviously made by tornadoes.

Three areas of 2200, 1700, and 400 acres consisted of fallen timber overgrown with vines and brush.  Many smaller areas of fallen trees less than 20 acres in extent were also recorded.  Tornadoes, thunderstorm down bursts, and ice storms caused these natural formations (or malformations).  Fallen trees provide all sorts of habitat and forage opportunities for many species of animals. 

During winter floods near rivers made it difficult for surveyors to do their work.  Floods killed trees and created standing deadwood.  Fallen woody debris often blocked rivers, preventing navigation. 

Surveyors recorded devastating unchecked fires.  One found an area of burned land 6 miles long. 

The earthquake of 1811-1812 formed elliptical depressions that surveyors called “earthquake swamps.”  The land actually sank below the water line, killing every tree in the depression. 

Surveyors reported pimple mounds–high circular swells of 6-30 feet in length.  Geologists later studied these mounds and determined they were formed 700-2400 years ago when severe extended droughts left many places bare of vegetation.  Winds blew sand into little dunes that later became covered with vegetation after the rains returned.

Photo of a pimple mound from google images.


Bragg, Don C.

“Natural Presettlement Features of the Ashley County, Arkansas Area”

American Midland Naturalist (2003) 149 (1-20)

Packovacs, Eric P. ; et. al.

“Genetic Evaluations of a Proposed Introduction: The Case of the Greater Prairie Chicken and the Extinct Heath Hen”

Molecular Ecology (2004) 13 1759-1769

Ryan, Mark R.

“Breeding Ecology of Greater Prairie Chickens (Tympanuchus cupido) in Relation to Prairie Landscape Configuration”

American Midland Naturalist (July 1998) 140 (1)

Monstrous Clouds of Salt Marsh Mosquitoes (Aedes sp.)

October 2, 2011

Photo from google images of Aedes sollicitans, the common salt marsh mosquito.

Early colonists reported seeing clouds of salt marsh mosquitoes that would block out the sun.  European settlers may have enjoyed a bounty of fish, waterfowl, and game but life in the unspoiled wilderness had its drawbacks.  Salt marsh mosquitoes swarmed so ferociously that few American Indians chose to live on barrier islands.  The ones that lived there were likely forced to the seaside by bigger, stronger tribes they feared.  John Lawson, an early explorer of the Carolinas, settled inland too, specifically touting the benefits of fewer mosquitoes there than on the coast.

Even today despite well funded mosquito control programs, the number of salt marsh mosquitoes is astounding.  One square yard of salt marsh can produce one million mosquitoes.  Researchers can vacuum them off the marsh at a rate of 10,000 per minute.  Ocean breezes keep the blood-suckers off the beaches, but I well remember hurried walks on the boardwalks between the beach and a Harbor Island rental condo because of mosquitoes that lurked in the back dunes.

There are two species of salt marsh mosquito–the brown (or black) Aedes taenorhynchus and the common Aedes sollicitans.  Both lay their eggs in depressions or cracks in silt and detritus above the normal high tide line.  Their eggs can survive droughts for as long as six months.  They range along the coast from New England to Brazil, successfully occupying the extensive habitat for which they’re named.  Brown salt marsh mosquitoes don’t even need a blood meal to produce eggs.  If the larva of this species had a good supply of microscopic food (they eat bacteria, protozoa, rotifera, and fungal spores), the adult female can lay 25-75 eggs, though this number increases to 200 after a successful blood meal.  The other species of salt marsh mosquito does need a blood meal to produce eggs.

Salt marsh mosquitoes mostly feed at dawn and dusk.  They torment many animals including deer, rabbits, birds, alligators, crocodiles, sea turtles, and snakes.  Nocturnal raccoons usually avoid them because mosquitoes become less active at night.  Cooler temperatures slow them down, and hungry bats become active, so mosquitoes spend this time hiding in foilage.  Salt marsh mosquitoes harbor only one known parasite–dog heartworm.

During the Pleistocene salt marsh mosquito populations were likely highest during interglacials and interstadials which were characterized by warmer wetter climate and barrier island formation.  This led also to more salt marsh habitat.  Cool, dry, windy stadials undoubtedly diminished their numbers.  Mosquitoes don’t thrive in drought-like conditions, nor can they endure cold temperatures and high winds.  Yet, they did manage to survive Ice Ages–the coast remained warm enough.  Large mammals become immune to mosquito bites and won’t itch, though they do lose blood.  Thick-skinned beasts such as mammoths probably didn’t even notice mosquitoes after they’d developed this immunity.

There was no malaria or yellow fever in Pleistocene North America.  Malaria is caused by two species of plasmodium (a type of protozoa).  Several species of North American anopheline mosquitoes can host these parasites, but the parasites themselves didn’t live in North America.  Instead, infected Europeans and Africans carried the parasite in their blood when they came here and malaria spread when an infected human was bitten by a New World mosquito capable of hosting the parasite.  Yellow fever is spread by a frost intolerant invasive species–Aedes aegypti–which dies out during winter.  Yellow fever is caused by a virus carried by Aedes aegypti and was less common because frost wipes out this mosquito.

The Richmond County Mosquito Control Department is located 5 minutes from my house.  They waste a lot of pesticide.  I occasionally see them spray the sides of Piney Grove Road where the water never remains long enough for larva to survive.


A review of the New Television Series, Terra Nova.

Hey, Spielberg stole my idea, but instead of going back 36,000 years, he sent his fictional characters back 85 million years .  I was going to accuse him of stupidity–why would people want to go to the miserable climate of the Cretaceous when they could be living in the more familiar and comfortable Pleistocene?  But there is a plausible explanation–the crack in time leads to a wormhole that specifically goes to 85 million BP.

I’m going to accuse Spielberg of stupidity anyway, or at least of insulting people’s intelligence.  There were two scientific innacuracies in the pilot episode that I couldn’t stomach.  Sauropods were the first dinosaurs depicted on the show.  Sauropods were absent from the North American continent between 100 million and 70 million BP.  The shows producers don’t specify which continent this is all taking place on, but I bet, if asked, they would say North America.  They probably haven’t even though of it.  There is another inaccuracy that might not seem like a big deal to most, but it bothers me.  In the back ground there is grass.  Grass didn’t evolve until the Oligocene.  An accurate background scene would have a mixture of bare soil, a carpet of moss, and an open forest of conifers.

I might forgive these ignorant errors, if the show was entertaining but it’s not.  I could only endure the first 45 minutes.  When a rebellious teenage son refused to respect his, until recently, absent father–a very tired storyline already done 16,742 times on daytime soaps and family dramas–I gave up on this dreck.  What’s the show’s fatal flaw?  It’s boring.

Here’s a list of television shows I recommend instead–Outer Limits reruns (on Hulu and Chiller), Breaking Bad (on AMC), The Walking Dead (on AMC), Boardwalk Empire (on HBO),  Curb your Enthusiasm (on HBO), and Supernatural (on CW).