The Shrinking Brain

July 5, 2015

Humans (Homo sapiens), like all other organisms, are continuously evolving, and the forces that shape human evolution have also changed.  Before the development of agriculture, ecological pressures were the primary influence on human evolution.  Human populations were scattered and low.  Each individual had to work and think harder then because survival in primitive environments required greater endurance and intelligence.  Pleistocene Homo sapiens had to do it all.  On average Cro-magnon man, also known as European early modern humans, had larger jaws and teeth, a bigger lung capacity, and a larger cranial capacity than present day man.  The average cranial capacity of a human being living 20,000 years ago was 1500 cubic centimeters compared to 1350 cubic centimeters for an average human today.  This larger brain capacity does mean they were more intelligent, but of course lacked our present day knowledge.  During the agricultural revolution social competition replaced ecological processes as the primary influence on human evolution.  This led to a division of labor, reducing the need for such a large cranial capacity.  Human intelligence has declined all over the world since.

Shrinking Brain in Humans

Modern humans have a smaller brain capacity than their recent ancestors.  Incidentally, this illustration is misleading.  Homo sapiens did not evolve from Neanderthals.  Instead, Homo sapiens and Homo neandethalis shared a common ancestor–Homo heidelbergensis. Homo Neanderthals were also a distinct species, not a subspecies.

Domesticated cattle, sheep, goats, and dogs also have smaller cranial capacities than their wild ancestors.  Humans culled the larger, wilder individuals; creating tamer breeds.  Humans culled people who didn’t conform to society’s rules as well.  In this way humans may have eliminated many people with larger brains that just couldn’t fit in.  One study of a primitive society in New Guinea showed that as much as 10% of the males were executed because they couldn’t follow society’s rules.  The death penalty selects for tamer humans by eliminating aggressive individuals from the gene pool.  The death penalty was also common in western societies until the 20th century.

Aggressive intelligent humans had a big advantage over tame humans when the world was a wild place.  But some of the characteristics that favored survival in a wilderness are counterproductive in a civilization  dependent upon the rule of law to prevent chaos.

Human cranial capacity is on the increase again.  Over the past 200 years there has been a major improvement in the average human’s diet.  Better nutrition is leading to larger cranial capacities.  The brain is a large fatty organ that requires a great deal of energy.  With a better food supply humans with large brains are more likely to survive.  However, I believe this recent trend is temporary.  I predict future generations will suffer from greater incidences of malnutrition as the world population outstrips the ability of farmers to produce enough food for everybody.

References:

Bailey, Drew; and David Geary

“Hominid Brain Evolution: Testing Climatic, Ecological, and Social Competition Models”

Human Nature 2009

McAuliffe, Kathleen

“If Modern Humans are so Smart, why are our Brains Shrinking?”

Discover Magazine 2010

How to sell Books with a Misleading Premise

June 30, 2015

I finished reading The Invaders: How Humans and their Dogs Drove Neanderthals to Extinction by Pat Shipman, and it left me shaking my head in confusion.  The author debunked the title of her book on page 213 when she wrote “…there are no well-dated Neanderthal sites younger than about 40,000 years ago; all are older.  Unless future finds show wolf-dogs in even earlier sites, Neanderthals were extinct by the time wolf-dogs appeared.”  If Neanderthals were extinct by the time humans supposedly began working with “wolf-dogs,” the human-dog connection can’t possibly be the reason Neanderthals became extinct.  I think the author invented a sensationalist title to sell copies of a book that is based on a completely unfounded premise.  Perhaps it was the publisher’s idea.  The last chapter of this book seems to be an incoherent add-on.

The Invaders: How Humans and Their Dogs Drove Neanderthals to Extinction

The author of this book convincingly refutes her own premise.

The premise of her book depends upon 1 highly controversial study.  This study used a complex statistical analysis of dog and wolf skull measurements to differentiate between the 2.  These scientists measured a skull from Goyet Cave, Belgium; dating to 36,000 calendar years BP, and determined it had a 99% chance of being from a dog.  Prior to this find, it was thought humans didn’t domesticate dogs until about 14,000 BP.  Some other canid skulls measured in this study, dating to older than 14,000 BP, were also determined to be dog rather than wolf.  However, another study (referenced below) completely contradicts this conclusion.  These scientists used a 3-D morphometric analysis of the same ancient canid skulls and determined the Goyet Cave specimen and others of similar age were wolf, not dog.  A DNA study of these specimens determined these particular canids were not ancestral to modern dogs or extant wolves.  They were probably just an extinct ecomorph of wolf.  Alas for Pat Shipman, her hypothesis is a poorly reasoned fantasy.

Humans didn’t need dogs to rub out Neanderthals.  Humans likely had far superior organizational skills as well as advanced technology such as projectile weapons and knitting needles.  Humans could survive in a colder climate with better clothing and could successfully hunt animals on open plains.  I’m certain humans beat Neanderthals in battle by using strategy and tactics.  I do think humans were the sole factor in the extinction of Neanderthals.  If Homo sapiens never colonized Europe, Neanderthals would still be there today.  Climate change can’t be the reason for their extinction because Neanderthals survived dozens of dramatic shifts in climate phases during their >250,000 year occupation of Europe.

I found a couple of other minor mistakes in The Invaders worth noting.  This isn’t a big deal–I know there are mistakes on my blog, but I’m too lazy to go back and edit corrections.  The late surviving population of mammoths on Wrangel Island lasted until 4000 BP, not 3000 BP, and they were not a dwarf population as Pat Shipman mistakenly claimed.  They were fully-sized woolly mammoths (Mammuthus primigenius).  She also reproduced a graph in her book from a study that mistakenly classifies the aurochs (Bos taurus), the ancestor of modern cattle, as a steppe environment inhabitant.  The aurochs favored habitat was riparian woodland.  Cattle need frequent access to water and are not well adapted to arid grassland habitat.

Reference:

Drake, Abby; et. al.

“3D Morphometric Analysis of Fossil Canid Skulls Contradicts Domestication of Dogs during the Late Paleolithic”

Scientific Reports 2015

Did Neanderthals (Homo neanderthalis) really Interbreed with Humans (Homo sapiens)?

June 26, 2015

Warning: Do not read this blog entry, if you are younger than 18.  The nude images might cause blindness.

A new study published in the scientific journal, Nature, of a 40,000 year old skull suggests Neanderthals (Homo neanderthalis) interbred with humans (Homo sapiens).  This particular specimen, found in Romania, is thought to be 6%-9% Neanderthal, and the authors of this study think this individual had a great-great-great-great Neanderthal grandparent.  He left no living  descendants, but other studies of Neanderthal DNA determined Homo sapiens and Homo neandetheralis did hybridize, and some modern Europeans and Asians might be 1%-3% Neanderthal.  The media likes this story, and a study casting doubt on the assumptions used to identify past hybridization is being ignored.  I didn’t even see the study listed in the new journal article’s references, so the scientists involved in Neanderthal DNA studies are unaware of the article or are ignoring it as well.

The ignored study, referenced below, was written by A. Ericksson and A. Manica.  They write “tests for hybridization rely on the degree to which different modern populations share genetic polymorphisms with genomes of other hominins.”  A polymorphism is defined as 2 clearly different phenotypes existing in the same population of a species.  A phenotype is the composite of an organisms observable characteristics.  For example a population of humans could consist of big blondes and small brunettes–2 different phenotypes.  The authors of this study show that examples of shared polymorphism attributed to hybridization could actually have originated before H. neanderthalis and H. sapiens diverged over 200,000 years ago.  Both species of humans evolved from H. heidelbergensis.  The population of H. heidelbergensis that colonized Europe evolved into H. neanderthalis.  The population of H. heidelbergensis that stayed in Africa until ~45,000 years ago evolved into H. sapiens.  An Asian colonization evolved into the poorly known Denisovans.

The authors of this study believe their findings don’t rule out the possibility of hybridization in Europe, but they urge “caution” when making the assumption that hybridization occurred.  To determine whether or not the degree of shared polymorphism was the result of hybridization or was part of an earlier genetic pattern from the founding population structure would require DNA from a specimen pre-dating the divergence of these 2 species.  Viable DNA can’t be extracted from specimens that old.

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Representation of a female Neanderthal based on DNA studies.  Note the red hair.  Neanderthals had red hair.

Nude female Homo sapiens.  Human women are much cuter than Homo neanderthalis.  Moreover, female Neanderthals were probably considerably stronger than male Homo sapiens.  I doubt the 2 species interbred.  Genetic studies can’t discern certain hybridization without studying the DNA of the ancestral common ancestor of both species.  This is impossible because those fossils are too old to harbor DNA.

I doubt H. sapiens bred with H. neanderthalis.  The 2 populations of humans had been isolated from each other for over 200,000 years.  Behavior patterns likely dramatically differed. Facial features were significantly different, and I think they didn’t recognize each other as mating material.  Neanderthals were intelligent ambush predators that used thrusting weapons, and they were physically more powerful than humans.  But humans were smarter and had developed projectile weapons.  Humans ate a wider variety of foodstuffs, contributing to greater fertility.  I think humans wiped out Neanderthals within a few thousand years.  Assimilation was unlikely.

Reference:

Ericksson, A.; and A. Manica

“Effect of Ancient Population Structure on the Degree of Polymorphism Shared between Modern Human Populations and Ancient Hominins”

PNAS 2012

http://www.pnas.org/content/109/35/13956.full

The North Georgia Zoo

June 23, 2015

On the way home from our stay in Helen, Georgia we stopped to visit the North Georgia Zoo.  I was determined to see animals on this vacation.  The North Georgia Zoo is located in the middle of the boondocks about 15 miles west of Cleveland, Georgia.  The petting zoo costs $10 but to see the good stuff requires a payment of $26 per adult and visitors must be accompanied by a guide.

My favorite animal was a cousin of the human race–a white handed gibbon.  These lesser apes are social animals but the owners of the North Georgia Zoo were unable to attain a companion gibbon, so they raised it with 2 basset hound puppies.  The 2 now fully grown dogs share the cage with the gibbon who likes to ride on their backs.

The zoo is home for several species of kangaroos and wallabies including the largest kind–a red kangaroo.  That individual was relaxing in the shade on the ground with his back toward us, and I didn’t get a good photo.  But a smaller gray kangaroo was hopping back and forth.

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Llama.  I saw a couple fighting and spitting their cud at each other.  Yuck!

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African crested porcupine.  This individual was friendly.  Audubon said porcupines made good pets.

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Collared peccary.  I could see its sharp teeth when the zookeeper fed it a carrot.

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This kangaroo stopped hopping just long enough for me to photograph it.

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New Guinea singing dog.

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White handed gibbon.

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A seriema–the closest living relative of the extinct terror bird.

The zoo has a cougar, a serval, a caracal, and an Eurasian lynx.  I noticed the cougar was behind a double switching cage.  The guide said it’s not a good idea to be inside the cage when the cougar is feeding.

The New Guinea singing dogs have an interesting history.  They are closely related to Australian dingoes.  Seafarers from the subcontinent of India brought dingoes to Australia about 4300 years ago. These same seafaring people visited New Guinea and some of their dogs escaped and established a population here as well during this same time period.  Since then, the New Guinea singing dogs evolved some differences from dingoes and other dogs.  They are shorter than dingoes and have broader skulls, and they can climb trees.  Oddly enough, the females have a peculiar vocalization during copulation.  In general they are noisy “singing” dogs, hence the name.  Dingoes also live in southeastern North America where they are known as Carolina dogs.  Paleoindians brought them to America from Asia.  Dingoes and singing dogs are very similar to the first dogs domesticated by humans.  Reportedly, dingoes make good pets but are harder to train than most dogs and have a tendency to escape captivity.  The ones I saw at the zoo seemed a bit high strung.

I took photos of a llama and a peccary.  These animals were common throughout southeastern North America during the Pleistocene.  The zoo even had a seriema–the closest living relative of the terror bird.

The North Georgia Zoo is a noisy place.  A patron can hear a wolf howling, New Guinea dogs singing, the howls of basset hounds and gibbon, and the crowing of a peacock.

Friendly sheep dogs roam the grounds at night and protect the zoo animals from coyotes, foxes, and bobcats.

The deer and kangaroos could jump over the fences and escape, if they desired, but they are satisfied with their easy life in captivity.

Helen, Georgia and Anna Ruby Falls in Unicoi State Park

June 19, 2015

We stayed at the River Bend Hotel in Helen, Georgia; a tourist trap located in White County.  All the buildings are mandated to look like Bavarian village houses.  Few, if any, German immigrants settled here.  Instead, the whole town was dreamed up as a gimmick by Pete Hodkinnson in 1969 because he happened to like the look of rural German architecture.  I got bored with Helen after about an hour.  I did find a store specializing in exotic jerky.  They sell beef, buffalo, goat, elk, venison, kangaroo, marlin, tuna, salmon, and python jerky.  They also sell smoked rattlesnake in a small can for $20.  I bought a package of elk jerky.

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We stayed at the Riverbend Hotel.  This is the view of the Chattahoochee River from our hotel room.  The poor manager looked overworked.  I asked if he was hiring.  He admitted he was doing the jobs of 8 people.  Only a few hundred people live in Helen.  It’s hard to find people willing to drive from out of town to work for minimum wage and tips.

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This was the only bad thing about our hotel…the slick steep wheelchair ramp.  I dreaded pushing my wife up and down it every time.  I had to take my shoes off for traction.

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This hemlock tree has had the top removed but all of the other hemlock trees in Helen and Unicoi State Park look healthy.

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View up the Chattahoochee River from Helen.  It’s a good trout stream.

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We ate supper at the Old Bavaria Inn.  Overpriced and no better than my own cooking.

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George Costanza wasn’t joking.  There really is a jerk store.

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The whole town is mandated to look like a Bavarian village.  What a gimmicky tourist trap.

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Daphne and I went tubing down the river.  We saw a common water snake.

I was more interested in the nature in and around Helen than the faux German façade.  My daughter and I floated on tubes down the stretch of the Chattahoochee River that flows through town.  We spotted a common water snake.  I thought fish density was low in this part of the river–I looked through the clear water for fish and saw just a few darters.  But 1 morning I saw some serious trout fishermen with a string of 24 small brook trout.  I told them I didn’t think there were any fish in the river because I didn’t see any. The older fisherman said, “you can’t see them, but they could catch their limit of 8 in an hour or two.”

The most common birds in town were chimney swifts, robins, catbirds, and city pigeons.  The chimney swifts nest under bridges and hunt mosquitoes and flies.  I saw 6 chimney swifts mobbing a crow–behavior I’d never seen before.  On the way to Helen I saw a kingbird chasing an hawk at great speed, and the hawk turned in the air and tried to catch the kingbird to no avail.  Turkeys were visible in the fields and woods north and south of Helen.  Common trees along the Chattahoochee River here include silver maple, sycamore, sweetgum, hemlock, black walnut, river birch, tulip, and cottonwood.

The Old Bavaria Inn serves $21 entrees and $10 sandwiches, and of course, beer ranging in price from $3-$15 a glass.  I ate an 1/2 reuben sandwich with a cup of goulash.  It was the best reuben I’d ever had because the sourkraut was seasoned with bacon.  Their goulash was good but not as good as mine–I prefer more paprika and less salt.  The Rib Country Restaurant serves baby back ribs, pulled pork, and grilled hamburgers; all for $10 or less.  Their ribs are excellent, and their potato chips are made from scratch.  At the Bohemian Bakery and Café I had a delicious bratwurst wrapped in a flaky pastry, like pigs-in-a-blanket.  The side was even better–cooked red cabbage dressed in a creamy horseradish sauce.  Good luck trying to find a restaurant in Helen that serves fresh vegetables and fruit.  Just about all of them throw potato chips on the plate and offer no vegetables aside from slaw.

We visited Anna Ruby Falls in Unicoi State Park located about 15 minutes north of Helen.  The trail to the falls is a .4 mile hike up a paved but steep trail through a beautiful shady forest of tulip, hemlock, mountain chestnut oak,  hickory, maple, and mountain laurel.  The hemlock trees here appear to be healthy.  These are impressive falls.  I thought the forest around the falls was virgin because of the rugged terrain, but apparently after the Civil War some men  cut the original forest down.  They went broke–those despoilers of nature sent the felled timber down the rapid stream, and the wood was smashed to smithereens against the rocks.  Served them right for ruining such a gorgeous spot.  The forest now must be  over 120 years old.  At the beginning of the trail tourists can feed the trout congregating in a rocky pool.  I did see a few small ones, maybe 6-8 inches long.

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This chestnut tree in Unicoi State Park shows evidence of blight damage but the specimen next to it is twice as tall and still healthy.

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The bottom of Anna Ruby Falls.  It was nice and cool here in the shade by running water.

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The top of Anna Ruby Falls.

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The other side of Anna Ruby Falls.  The falls are bisected by dry rock covered by vegetation.

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Mountain laurel.

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Rock shelter.  Signs warn of rattlesnakes and copperheads but I didn’t see any snakes here.

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Great clouds of pretty blue butterflies fluttered throughout the trail to the falls.  Here are some drinking from a mud puddle.  They look white in the photo. I think this species is known as the spring azure (Celastrina ladon).

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Lake Smith in Unicoi State Park.  We picnicked and swam here.  I was on the look out for hot chicks in bikinis but kept seeing fat people instead.

We picnicked at Smith Lake.  It’s manmade and full of bass, bream, and obese Homo sapiens.  The water is clear enough to see the fish.

Extensive Late Pleistocene to Mid-Holocene Wetlands along the Tennessee River

June 15, 2015

A paper about extinct giant beaver (Casteroides sp.) fossil remains in the mid south briefly mentions evidence for the existence of “extensive floodplain lakes and marshes along the middle stretch of the Tennessee River” during the late Pleistocene-mid Holocene.  This intrigues me. Following the end of the Ice Age, increased precipitation in the atmosphere from melting glaciers caused southeastern rivers to meander more than they do today.  Geologists actually refer to these river patterns as supermeanders, and supermeandering rivers were common between ~15,000 BP-~6,000 BP.  Meanders often get cut off from the main river channel, and they become oxbow lakes, a name that describes their curved shape.  Sediment eventually fills oxbow lakes, and during this process they become marshy.  Large oxbow lakes created by this period of supermeanders attracted huge flocks of wintering waterfowl.  Archaeologists found enormous quantities of mallard duck (Anas platyrhyncos) remains dating to the late Pleistocene-early Holocene in Dust Cave and Smith-Bottom Cave, both located in northwestern Alabama.  The ducks were brought inside the caves by early archaic Indians who enjoyed a steady diet of duck during the winter.  70% of the faunal remains in Dust Cave were birds, mostly waterfowl but also including passenger pigeon, bobwhite quail, and prairie chicken.

Diagram showing how oxbow lakes are formed.  There must have been huge oxbow lakes along the Tennessee River during the supermeandering phase of ~15,000 BP-~6,000 BP

Map of Tennessee River.  Abundant remains of ducks and other waterfowl in caves near the river suggest a very extensive wetland occurred along the middle stretch of the river during the Late Pleistocene-to mid Holocene.

Location in Lauderdale County and the state of Alabama

Caves are located  on both sides of the Tennessee River in northwestern Alabama.  They preserve evidence that early Indians ate a lot of duck.

Mallard ducks

Huge flocks of mallard ducks wintered on oxbow lakes and marshes along the Tennessee River during the late Pleistocene-mid Holocene.

Dust Cave was buried by sediment until ~15,000 BP when the nearby Tennessee River changed coarse and eroded through this sediment, exposing the cave entrance.  Indians occupied the cave from ~12,500 BP-5000 BP.  Archaeological evidence shows 5 succeeding cultures utilized the cave. The Indians buried their dead in Dust Cave and left plenty of archaeological evidence such as arrowheads and the impressions of textile weaving on clay.  Toward the end of this time, Indians utilized waterfowl less than their predecessors had and relied more on upland game.  This suggests wetlands and lakes in the region eventually were diminished in extent.

During the time of supermeanders swamp rabbits (Sylvilagus aquaticus) were common.  Flooding helped establish extensive stands of impenetrable bamboo cane (Arundinaria gigantea) known as canebrakes, a favored habitat of swamp rabbits.   Floods killed trees and deposited rich soil.  Bamboo cane thrives on open sunlit ground with well fertilized soil.

Swamp rabbits were abundant here as well.

The deepest lakes offered habitat for the freshwater drum (Aplodonitis grunniens).  This species prefers clear water with sandy or gravel bottoms.  They feed on mussels, insect larva, and small fish.  Freshwater drums, suckerfish, and catfish made up 8% of the faunal remains in Dust Cave.  Fish was an important summer food for Archaic Indians after ducks migrated north.

Freshwaterdrum.png

Indians ate freshwater drum.

The extinct giant beaver occupied the oxbow lakes and marshes created by the supermeandering patterns of the Tennessee River until Indians hunted them to extinction.  (A safe assumption, though no direct evidence of humans hunting giant beavers has ever been found.)  Perhaps, they even persisted here early in the Holocene because the habitat they favored was so extensive.  Remains of giant beavers have been found at 3 sites along the Tennessee River including Ruby Falls, Bell Cave, and ACb-3 Cave.  The latter 2 sites are located in Colbert County, Alabama.  There were at least 2 species of giant beaver–Casteroides ohioensis and Casteroides dilophidusC. ohioensis lived in the Midwest; C. dilophidus lived in Florida and south Georgia.  Scientists aren’t sure which species lived along the Tennessee River because not enough skeletal material was found to distinguish between species.  Giant beavers preferred the same habitat as the modern day muskrat (Onadatra zibethicus) and did not require wooded environments like extant modern beavers (Castor canadensis).

Photo: Giant Beaver, Castoroides ohioensis.

Giant beavers (Casteroides sp.) lived in these wetlands until the Indians overhunted them to extinction.

References:

Parmalee, Paul; and Russell Graham

“Additional Records of the Giant Beaver, Casteroides, from the Mid South: Alabama, Tennessee, and South Carolina”

Tributes to the Career of Clayton Ray, Smithsonian Series of Publications 2002

Pritchard, Erin

TVA Archaeology: 75 Years of Prehistoric Site Records

University of Tennessee Press

 

 

Pleistocene Pollinators

June 12, 2015

The media sure likes to generate panic.  It must be good for ratings.  Recently, American media outlets offered wall-to-wall coverage of the Ebola virus, a danger that eventually killed 2 or 3 people in the United States from a population of over 300 million.  During slow news cycles the media seems to always find some obscure disease of the month to fill air time.  Another constant well of media anxiety is anthropogenic-influenced climate change, even though its worst effects won’t be felt in our lifetimes, and there’s nothing we can do about it, unless people are willing to give up affordable electricity and cars.  A few years ago, media pundits started peeing in their pants about colony collapse disorder.  Without honeybees (Apis mellifera) they claimed there would be no pollination of fruits, nuts, and vegetables.   The world would have no fresh produce, and we’d be stuck with a boring diet of wind-pollinated grains.  In some regions their fear has come true.  In upstate New York colony collapse disorder wiped out so many honeybees, bee keepers were unable to provide any hives to help pollinate some apple orchards.  There was no loss of production. Orchards produced just as many apples without honeybees as they did with them.  Orchardists realized they’d been duped for decades by bee keepers into thinking they couldn’t grow fruit without paying for the rental of bee hives.

There are 140 species of native leaf cutter bees, including the blue orchard bee (Osmia lignaria), a species that is considered a better pollinator than non-native honeybees.  Moreover, there are many species of native bumblebees, butterflies, and wasps that pollinate flowers.  Native bees are such effective pollinators that honeybees were not missed at all.  As long as some natural areas are left in the vicinity of gardens and orchards, there will always be enough native pollinating insects; and honeybees will be completely unnecessary.  No need to worry about colony collapse disorder–many species of native bees are solitary and don’t nest in colonies.

Osmia-lignaria----WEB

Blue orchard bees are more effective pollinators than honey bees.

Southeastern blueberry bees and bumble bees pollinate my blueberry bushes.

Bumble Bee Queen

Bumblebee (Bombus impatiens)

I marvel at the lack of critical thinking among reporters and media pundits who are so quick to form opinions without realizing how illogical their conclusions are.  Europeans brought honeybees to North America 400 years ago, but before then, Native Americans successfully grew fruits and vegetables dependent upon insect pollination.  They farmed squash, beans, tomatoes, peppers, and plums.  Honeybees are just 1 species out of thousands of insect pollinators in America, yet the media know-it-alls led people to believe a nightmare scenario of no fruits or vegetables.  Not a single pundit during the panic of colony collapse disorder even realized honeybees are a non-native invasive species.  Usually, invasive species are another topic of unnecessary panic frequently reported upon by the media.

Thousands of species of American plants have depended upon insect pollinators for millions of years–ever since the evolution of flowering plants. The fossil record of these insects is scant.  When rare circumstances do occur that preserve ancient insects, the remains are usually so fragmentary they can’t be identified at the species or genera level.  Some nests of a species of leafcutter bee (M. gentillis) were found in the La Brea tar pits, California.  The same species still lives in the region today.  Studies of Pleistocene insects determined individual species adjusted their range according to fluctuating climate cycles, but no known large scale extinctions occurred during this era. (See: https://markgelbart.wordpress.com/2012/07/18/using-fossil-beetle-assemblages-to-determine-temperature-ranges-during-the-late-Pleistocene/) The insect pollinators we find in our yards today are the same species that lived during the Pleistocene.

Reference:

Bjerga, Alan

“Betting on Nature to Solve the Bee Crisis”

Bloomberg Business Week May 18-24, 2015

Pleistocene Man-Eaters

June 9, 2015

The sum total of paleoindian skeletal material ever discovered could fit inside a single coffin and with room to spare.  This isn’t true of Pleistocene Homo sapiens  remains found in Europe where bogs and caves are more common than in America.  Also, humans lived in Europe for tens of thousands of years, whereas humans occupied the vast spaces of America for just the last few thousands years of the Pleistocene, another factor that explains this disparity in abundance of remains. The rarity of human fossil remains from America makes it impossible to determine how often Homo sapiens fell prey to large predators on this continent.  Despite the absence of evidence, I have no doubt America’s large carnivores were man-eaters at least some of the time.  The sole mystery, one that will probably never be solved, was the frequency of this behavior.

Humans are still part of the food chain.  The region including India and Nepal provide the best evidence for this.  The people who live here have long held a respect for animals.  The Hindu faith predominates in this region and with it comes a tradition of not destroying wildlife.  A large and growing population of people living side by side with dangerous carnivores has resulted in countless cases of man-eating tigers (Panthera tigris) and leopards (Panthera pardus).  The Champarat tiger killed 430 people in the early 20th century.  The Panar leopard killed 400 people circa 1910.  The leopard of Rudraprayag killed 126 people over an 8 year period until a hunter shot it in 1926.  Between 1907-1938, 33 different man-eaters killed an estimated 1200 people.   Today, leopards kill more people in India than any other large predator because they are still relatively common while tigers are rare.  But in the Sundarbans region, where the world’s largest mangrove forest grows, tigers killed 50-60 people a year until recently when management practices greatly reduced this annual toll.

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A tiger vs. an unarmed Homo sapiens is a mismatch.

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Leopards kill more people in India than any other carnivore.

An unarmed man is no match for a big cat.  Tigers can drag an 800 pound cow for 2 miles.  Jim Corbett, a famous hunter of man-eaters, tracked a tiger that dragged an 800 pound cow up a steep hill for over a mile.  At 1 point the cow’s leg got stuck between 2 saplings, but the tiger yanked the cow free, tearing the leg off where it got left behind, snared on the tree saplings.  That kind of strength is astounding.  They can crush a human’s skull with just a paw blow.  In addition to this awesome brute strength, sharp claws and teeth can sever an artery and cause quick death through loss of blood.  Leopards are even known to attack and kill full grown gorillas (Gorilla sp.), an ape that is much more powerful than a human.  Most man-eaters suffer some type of injury that prevents them from hunting their usual prey, but sometimes they just develop a taste for human flesh.

Paleoindians had throwing spears, clubs, and knives.  Just as importantly, they lived in groups and could gang up on an aggressive carnivores.  Their weapons were an equalizer, and their teamwork gave them an edge in most encounters.  Still, I’m sure the beasts won some battles.  In some cases I believe whole tribes were annihilated by individual man-eating predators.  A sneaky big cat could have potentially carried off 1 human every few nights for a couple months until there were no tribe members left.  Paleoindians surely built stout structures to shelter them from dangerous animals as well as from inclement weather.  When men were hunting, sturdy lodges were needed to protect the women and children.

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How many paleo-indians were killed by Smilodon fatalis and Arctodus simus, the 2 carnivores depicted in this image?  Incidentally, the giant short-faced bear was not as long-limbed as drawn in this illustration.

Here’s a list of the large carnivores that at least occasionally preyed on paleoindians: sabertooth (Smilodon fatalis), scimitar tooth (Dinobastis serum), giant lion (Panthera atrox), jaguar (Panthera onca), cougar (Puma concolor), dire wolf (Canis dirus), timber wolf (Canis lupus), dhole (Cuon alpinus), giant short-faced  bear (Arctodus simus), grizzly bear (Ursus arctos), black bear (Ursus americanus), and polar bear (Ursus maritimus).  Paleoindians won the war against these predators.  I believe they actively hunted them.  Perhaps, paleoindians purposefully killed as many prey animals as they could to eliminate the large carnivores’ food supply.  The extinction of the Pleistocene megafauna may have been the result of a concerted effort by humans to make America a safer place to live.  The large carnivores that did survive learned to fear man and inherited a more timid attitude toward Homo sapiens.

A Pleistocene Species of Bison (Bison antiquus) Survived in Canada until 4830 Calender Years Ago

June 5, 2015

The terminal radiocarbon dates for North America’s Pleistocene megafauna consistently translate to about 12,000 calendar years BP.  Because these dates are so consistent for so many different species, scientists assume Pleistocene megafauna became extinct 12,000 years ago.  I hypothesize this date reflects when these species became rare and local in distribution and not when these species actually became extinct.  The chance that bones will become preserved in the environment for thousands of years is low and depends on unlikely circumstances.  For example a flood has to rapidly cover remains of an animal with sediment before scavengers consume the carcass, and the soil chemistry has to have anti-bacterial qualities that prevent microbial consumption.  Then, a man has to be lucky enough to even find it.  An animal had to have been abundant in its environment to appear in the fossil record. I believe most species of Pleistocene megafauna continued to exist more recently than 12,000 years ago, but most more recent populations happened to live in areas where the process of bone preservation was uncommon.

There is evidence supporting my hypothesis.  The discovery that mammoths lived on the Pribiloff Islands until 5000 years ago is well known.  Some suppose the geographical isolation of the island temporarily sheltered the mammoths from the continental extinction event (caused by anthropogenic activity or environmental change) of 12,000 years ago.  But DNA evidence in Alaskan permafrost shows that mammoths and horses survived on the North American continent as recently as 9000 years ago.  Though there are no known fossil remains this young, the sedaDNA in frozen soil is evidence mammoths and horses were shedding hair, shitting, and pissing in Alaska several thousand years past the commonly accepted extinction date.  A less well known specimen, the Kenora bison, also supports my hypothesis.

Kenora is located in Ontario

Kenora is in the western part of Ontario.  This region supported a relic population of Bison antiquus as late as 4830 BP.

 

 

bison outline.jpg

Size comparison between modern day bison on the left and Bison antiquus on the right.  DNA evidence suggests modern bison evolved from Bison antiquus, but apparently, there was a relic, geographically isolated population of the Pleistocene bison in Canada as recently as 4830 years ago.

Jerry McDonald identified the Kenora bison as Bison antiquus, an extinct species formerly known from just the Pleistocene.  Carbon dating of the bones yielded a calendar year date of 4830 BP.  The bones of the specimen were found by a man excavating a peat bog near Kenora, Ontario, Canada.  This specimen apparently died of old age in a pond and was later covered by 14 feet of sediment.  It survived a broken jaw and suffered from malnutrition.  This individual was not getting enough calcium in his diet, but neither the broken jaw nor deficient diet caused his demise.  The Kenora bison lived in an environment interpreted as a pine/oak woodland.  (I studied the pollen graph included in Dr. McDonald’s paper and determined the trees in order of abundance were pine, birch, alder, oak, and spruce.)   Lily pads covered the pond the bison died in.  Perhaps, he was enjoying a last meal of lily pads before he collapsed.  This specimen is the northeasternmost known occurrence of this species.

Bison antiquus evolved from Bison latifrons, an even larger, longer-horned species, about 24,000 years ago.  Bison antiquus averaged 30% larger than modern bison (Bison bison) and had significantly larger horns and longer limbs.   However modern bison have bigger thighs and are better runners.  Scientists believe human hunters shaped the evolution of Bison antiquus to Bison bison.  During the Pleistocene big cats preyed upon Bison antiquus.  In response to this environmental pressure Bison antiquus were large and powerful, enabling them to fight off lions and saber-tooths when in prime condition.  But humans presented a different challenge.  In response to human hunting pressure smaller bison that reached sexual maturity at a younger age were more likely to survive and reproduce.  Smaller, more rapidly reproducing bison replaced the larger more powerful bison.  This is an excellent example of natural selection.  Human hunting pressure also selected for bison that tended to migrate long distances.  Bison antiquus already had migratory tendencies, but the presence of human hunters intensified this habit.  Bison that traveled for many miles away from humans were more likely to survive.

DNA evidence supports the assumption that modern bison evolved from Bison antiquus beginning about 12,000 years ago.  Bison antiquus was genetically much more diverse than modern bison.  Every clade became extinct, except for the 1 that led to modern bison.  This clade was well adapted to survive in an environment with human hunters and soon spread throughout western North America.  Some scientists regard the species of bison that lived from 12,000 BP-5,000 BP to be an intermediate form between Bison antiquus and Bison bison.  It’s known as Bison occidentalis.

The Kenora bison must have been from a relic population of Bison antiquus, geographically isolated from the clade that evolved into Bison bison.  Perhaps the 2 populations were separated by dense forest, unsuitable for bison.  This population of Bison antiquus lived in a region with a low density of human hunters.  Some time after 4830 BP, this population became extinct.  They were either overhunted by man or became genetically swamped by interbreeding with Bison bison as the newer species expanded its range east.

Incidentally, I believe megafauna in southeastern North America were probably the first to be wiped out by humans.  This region has the best climate and year round food resources in North America, and therefore supported the earliest population of Indians dense enough to impact megafauna populations.

References:

McDonald, Jerry; and George Lammers

“Bison antiquus from Kenora, Ontario, and notes on Evolution of North American Bison”

Tributes to the Career of Clayton Ray: Smithsonian Series Publication 2002

Wilson, Michael; Leonard Hills, Beth Shapiro

“Late Pleistocene Northwest Dispersing Bison antiquus from the Bighill Formation, Gallelli Gravel Pit, Alberta, Canada, and the fate of Bison occidentalis”

Canadian Journal of Earth Science 45 2008

New Trout Cave, West Virginia

June 2, 2015

No scientist has written a comprehensive paleoecological review of the fossil remains excavated from New Trout Cave, West Virginia.  Bones of mammals, birds, reptiles, amphibians, and fish were found in well stratified deposits here dating from 13,000 BP-over 50,000 BP.  The composition of species represent different climatic stages, making this a valuable site for ecologists interested in how faunal composition changed over time.  This blog entry is my layman’s review based on information I gathered from the paleobiology database and individual papers written about the vampire bat and pika remains dug from the cave.  A paper written about the reptiles and amphibians found here was published in an obscure journal I can’t obtain with convenience.  The bird and fish remains are completely undescribed in the scientific literature.  My review is entirely based on the ~50 species of mammal remains from the cave.

 

 

Map of West Virginia highlighting Pendleton County

New Trout Cave is located in Pendleton County, West Virginia.

Many of the species excavated from the cave were typical of those preyed upon by owls.  These smaller species prefer specific environments, so they are a better indicator of nearby paleohabitats than larger species.  The full glacial environment of the West Virginia/Virginia border seems to have been a mix of cold arid grassland, especially at higher elevations; and boreal forests in the valleys.  I counted 9 species with a definite preference for spruce forests–snowshoe hare, least chipmunk, red squirrel, northern flying squirrel, porcupine, boreal bog lemming,  heather vole, rock vole, and pine marten.  All but the least chipmunk, boreal bog lemming, and taiga vole still live in West Virginia, a state that still hosts some spruce forests.

The highest elevations in this region must have included tundra-like habitat.  The Labrador collared lemming (Dicrostonyx hudsonicus) occurred here during the Ice Age when its present day range was covered by uninhabitable glacier.  The taiga vole (Microtus xanthognatus) is another rodent that prefers tundra habitat.  Caribou (Rangifer tarandus) were also comfortable in these tundra-like conditions but likely wandered down to lower elevations.  Pikas (Ochotona sp.), a relative of the rabbit, formerly lived at higher elevations in the Appalachians.  They are known from 9 Pleistocene-aged sites in the northeast, including New Trout Cave.  These adorable animals like to take refuge under boulders where they store the alpine vegetation they eat.  Grassy rocky balds formerly provided excellent habitat in the Appalachian Mountains, but pikas became extirpated in the east following the end of the Ice Age.  Pikas still live in the Rocky Mountains where they were able to adjust to warming climate by moving to higher elevations.

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Taiga vole.  They no longer occur anywhere near West Virginia.  The presence of this species in West Virginia 29,000 years ago is evidence winters were harsher here then.

Distribution of Microtus xanthognathus

Present day taiga vole range map.

Woodland Caribou

Caribou and white-tailed deer were the 2 species of deer that lived in West Virginia 29,000 years ago.

Dicrostonyx hudsonius map.svg

Present day range map of the Labrador collared lemming.

American Pika
The American pika, known today only from high elevations in the Rocky Mountains, lived in West Virginia during the late Pleistocene.
The short-faced skunk (Bracyhprotoma obtusata) is an extinct species known from just 6 sites, including New Trout Cave.  This small skunk was probably a denizen of spruce forests.  It never expanded its range north when the glaciers receded.  Instead, it died out, and no scientist has a good explanation for its demise.
The grassy cold hilltops that provided habitat for collared lemmings and pikas also attracted western prairie fauna, including badgers, 13-lined ground squirrels, plains pocket gophers, and prairie voles.  None of these species occur in West Virginia today.  Horses (Equus sp.), flat-headed peccaries (Platygonnus compressus), and helmeted musk-ox (Bootherium bombifrons) were among the larger mammals that preferred the open spaces, though horses are a semi-generalist animal that can live in woods, if patches of grass are available.  Remains of lions (Panthera atrox), bison (Bison antiquus), and woolly mammoths (Mammuthus primegenius)  were not found in New Trout cave but I strongly suspect they were a part of the faunal mix here during the Last Glacial Maximum.
Over 27 species recovered from the cave were temperate or generalist species such as woodchuck, southern flying squirrel, gray squirrel, eastern chipmunk, jumping mice, beaver, muskrat, southern bog lemming, pine vole, meadow vole, wood rat, cottontail rabbit, white tail deer, red fox, coyote, dire wolf, raccoon, black bear, weasels, Jefferson’s ground sloth, shrews, and bats.   I can’t determine from the information available whether they co-occurred with the boreal/tundra/grassland species or represent a fauna from a different climatic phase.  It’s likely relic temperate habitat persisted in valleys, even during full glacial climate phases.  Some beech, oak, and hickory probably grew among the spruce in protected moist coves.  I’m sure beavers were able to survive the harsher winters wherever waterways existed.  Black bears live as far north as Alaska, so they remained in West Virginia during the glacial maximum.  Jefferson’s ground sloths ranged as far north as Alaska as well and undoubtedly were capable of surviving harsh winters.  White tailed deer are at home in Canada today.  They may have roamed with caribou in mixed herds here then.  Following the end of the Ice Age, most of these temperate species increased in abundance here, while the boreal/tundra species retreated north or perished.
Some of the fossil remains found in New Trout Cave represent a warmer climate phase than enjoyed by residents of the region today.  The Pleistocene vampire bat (Desmodus stocki) and the Florida muskrat (Neofiber alleni) required mild winter temperatures.  The remains of the vampire bat were found at a level dated to about 30,000 BP, a time of a weak interstadial before the Last Glacial Maximum.  But they are probably older than this.  The scientists who studied these remains noted the reddish color of the vampire bat bones.  This color matched those of bones that were from much older sediment, including the Florida muskrat remains. The younger remains from the colder climate phase were lighter in color, and apparently, the older vampire bat bones “intruded” into this younger layer.

Round-tailed Muskrat Neofiber alleni.png

The Florida muskrat lived as far north as West Virginia during the late Pleistocene.  Fossils of this species were found in a deeper older level and were associated with vampire bats and an herpetofauna that suggests warmer winters than occur presently.

Distribution of Neofiber alleni

Present day range map for the Florida muskrat. 

Florida muskrats need standing water with year round green vegetation.  Modern day vampire bats can’t survive subfreezing temperatures, and it can be assumed Pleistocene vampire bats were also not well adapted to freezing temperatures, though because of their larger size, I believe they likely could withstand light frost.  During the Sangamonian Interglacial Pleistocene vampire bats were widespread across North America, living as far north along a line from northern California to West Virginia.  Even during this warm phase, some light frosts during winter must have occurred. ( See: https://markgelbart.wordpress.com/2011/10/24/the-pleistocene-vampire-bat-desmodus-stocki/)  They also may not have been year round residents in the northern parts of their range.  I believe they may have followed migrating herds of mammoths and mastodons north when those behemoths sought summer foraging grounds.

Incredibly, the presence of the Florida muskrat and vampire bat suggests West Virginia experienced winters as mild as present day south Georgia or north Florida during this ancient warm climate phase.  The remains probably date to the Sangamonian Interglacial (~132,000 BP-~118,000 BP) when climate was warmer than modern day temperatures.  We don’t know the exact date because carbon dating can’t be used to date anything older than 50,000 BP, and other types of radiometric dating may not be possible here.  West Virginia suffered a stunning climate reversal following this warm climate phase when arctic tundra species invaded the once forested hilltops, while vampire bats retreated south.

Reference:

Grady, Fred; et. al.

“Northernmost Occurrence of Pleistocene Vampire (Chiroptera: Phillostomidae: Desmodus stocki) in Eastern North America)

Tributes to the Career of Clayton Ray: Series Publications of the Smithsonian Institution

Mead, Jim; and Fred Grady

“Ochotona Lagomorphs from Late Quaternary Cave Deposits in eastern North America”

Quaternary Research 1996


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