Pleistocene Ravens (Corvus corvax)

October 31, 2014

Halloween is my favorite holiday, but this year I’m not in the mood.  My father slipped into a coma and died last week.  That real horror far overshadows the artificial scares of Halloween and makes them even seem kind of silly.  It had been shocking to observe the steady decline of a man who went from being able to play 2 hour tennis matches in 100 degreee F heat to someone barely able to make it from the living room to the bathroom.  The aging process is a real monster that can not be stopped.  We were able to give my dad a proper burial, but that is a luxury ancient humans didn’t always have.  Humans are part of the natural world, and for many other organisms our bodies are just a source of protein.  Pleistocene humans no doubt often died from accidents while hunting.  If fellow tribesmen failed to find the body, it became food for the wildlife.  In Eurasia and North America ravens probably consumed more human flesh than any other animal.  Ancient battlefields strewn with corpses attracted great flocks of ravens, and this species was unfairly considered an harbinger of death.  The true harbingers of death were the humans who killed each other, but superstitious people blamed the birds.

HALLOWEEN DARK CROW RAVEN FEEDING ON ZOMBIE HEAD CORPSE FIGURINE HORROR STATUE

Before the Age of Reason people thought ravens were a harbinger of doom because they saw them scavenging dead corpses on battlefields.  Of course, it was the humans who were the harbingers of doom.  People instigated the killing, then blamed the birds. This illogical thought process is typical of our species.

The raven is a bird of deep wilderness, and its range has contracted with the advance of human “civilization.”  In contrast to the raven, the crow (Corvus brachyrinchus) thrives in the vicinity of man and has increased in numbers.  Crows are more social and tolerate each other’s company, while nesting raven pairs defend their territories from other ravens.  This behavioral difference explains why nesting communal crows are better able to take advantage of concentrated anthropogenic resources such as agricultural fields and garbage dumps.  The nesting strategy of the raven makes more sense when food consists mostly of more irregularly available animal carcasses. 

Ravens are known as “wolf-birds” because they are often seen in the company of wolves, scavenging their kills.  Wolves can lose up to 45 lbs of meat per day to ravens, and some think they evolved pack behavior to help defend their kills from scavenging ravens rather than from other predators.

Ravens were more widespread in southeastern North America during the Pleistocene than they are today, though evidentally they were absent from Florida.  The only known raven nest site in present day Georgia is a cliff on Brasstown Bald Mountain, but raven fossils of Pleistocene-age have been excavated from Kingston Saltpeter Cave in Bartow County, Georgia, and Bell Cave in Colbert County, Alabama.  Before man altered the environment ravens may have been more common in the upper south than crows.  Ravens fed on the deceased individuals of Pleistocene megafauna herds.  Ravens disappeared from the midwest following the extirpation of bison in the 19th century, and likely also declined in abundance in the south following the extinction of the Pleistocene megafauna thousands of years earlier.  Ravens surely followed dire wolves around, much like they follow modern day wolf packs in the Rocky Mountains.

Jasper Wolf Kill 2012.01.13

 

 

 

 

 

 

 

 

 

 

 

Ravens are known as wolf-birds.  They hang around wolf packs for access to the meat from kills.  Wolves may have evolved pack behavior to fend off ravens.  During the Pleistocene ravens surely accompanied dire wolves.

Ravens are larger than crows growing up to 4 lbs compared to less than 1 lb for the latter.  Ravens have a 4 foot wingspan and like to soar.  Crows rarely, if ever, soar.  A large adult crow can be larger than a small juvenile raven, but there is still a distinguishing characteristic–the raven has a more rounded tail. Both are highly intelligent species with a reasoning ability that matches or maybe even exceeds that of a monkey.  And both species are omnivorous, capable of eating everything from insects, worms, birds’s eggs, and carrion to nuts, fruit, grains, garbage, and dog shit.

Common Raven - They are strong fliers and can hover like an American Kestrel or soar like a hawk.

Ravens soar with the wind, while crows generally do not. Note the rounded tail.  Crows have a square tail.

Genetic studies suggest there are  2 clades of ravens in North America.  The most common clade is the Holarctic found in Europe, Asia, Greenland, and North America.  The California clade is found only on the southern Pacific coast of North America, and this clade is more closely related to the Chihauhan raven (Corvus cryptoleucas) than to members of its own species in the Holarctic clade.  The California clade became isolated from the Holarctic clade some time during the Pleistocene.

 Reference:

Marzluff, John; and Tony Angell

In the Company of Crows and Ravens

Yale University Press 2005

Did Elk (Cervus elephus) Live in North America Prior to 15,200 BP?

October 27, 2014

A recent thorough study, combining radio-carbon dating and genetic evidence, suggests elk did not cross the Bering Landbridge and colonize North America until about 15,200 years ago.  According to this study, “there is no unequivocal fossil evidence that elk lived in North America prior to this date.”  However, not every elk fossil in North America has been radio-carbon dated, and I’ll explain later how it’s possible elk could have colonized North America before this date without contradicting the data in this study.  But first, I’ll summarize the pertinent findings of this paper which was published in The Proceedings of the Royal Society of Biological Sciences last year.

The authors of this study had difficulty even finding North American elk fossils that were thought to be older than 15,000 years.  They did find 5 but determined from tests of bone collagen that 3 had been misidentified and were either bison or horse.  The radiocarbon date on the 1 that was correctly identified as coming from a member of the deer family was 13,100 BP…within the proposed timespan.

Radio-carbon dating shows that elk have lived in northeast Asia for over 50,000 years.  (Radio-carbon dating can’t date fossils older than this.)  Scientists examined the DNA of almost 100 Pleistocene-aged and modern elk specimens from northeast Asia and North America.   They found that all living North American elk are descended from elk originating in east Asia.  North American elk apparently split from their Siberian ancestors about 15,000 years ago.

The environment of the Bering Landbridge experienced many changes over time.  It was underwater from 135,000 BP- 70,000 BP.  It rose above sea level between 70,000 BP-60,000 BP.  Between 60,000 BP-30,000 BP, sea levels fluctuated so that some times the region was inundated and at other times it re-emerged.  From 30,000 BP-11,000 BP  the landbridge re-emerged, but since the latter date, it has been submerged once again.  However, until about 16,000 BP the environment of the landbridge had little favorable elk habitat.  A relatively warmer and drier climate occurred here between 16,000 BP- 11,000 BP, and elk were able to inhabit the landbridge and colonize the rest of North America from this starting point.  Curiously, elk no longer live in Alaska because a cooler wetter climate pattern has caused their favored habitats to deteriorate here.

Archaeologists believe humans also crossed the Bering landbridge during the same time period as the elk migration, but archaeological evidence is scarce.  The presence of elk fossils in Alaska during this time period and the timing of this migration as a proxy for human migration supports their belief.  Because the climate was warmer and drier, these paleo-indians may not have been as culturally adapted to living in arctic conditions as the more recent native American inhabitants are here.

Elk in Tennessee.  This species may be a relatively recent member of North America’s fauna.  There is no unequivocal evidence of their presence on this continent until 15,200 BP.

Range map of elk.  Elk no longer occur in Alaska because habitat is not favorable there for their survival.  However, between ~16,000 BP- ~11,000 BP, climate there was relatively warmer than it is today, and elk were able to live in the region.  This is when scientists believe they crossed the Bering Landbridge and began colonizing North America. Humans without an arctic-adapted culture also crossed the Bering Landbridge during this time period.

I don’t dispute the data and conclusions of this fine study.  However, I’m not entirely convinced that elk did not occur in some regions of North America prior to 15,200 BP.  The unique environmental conditions on the Bering Landbridge between 16,000 BP-11,000 BP that allowed elk to migrate to North America probably occurred and re-occurred periodically throughout the Pleistocene.  It’s possible and even likely that elk would have crossed the landbridge during an earlier incarnation of this climate phase.  Scientists have been wrong before about the exact dating of animal migrations into North America.  Formerly, scientists assumed grizzly bears (Ursus arctos) did not colonize North America south of the Ice Sheets until about 13,000 BP when the glaciers receded.  But a few years ago, fossil evidence of a grizzly bear, dating to 21,000 BP, was found in Edmonton, Alberta.  All it would take to prove that elk lived in North America prior to 15,200 BP would be 1 specimen dating to a greater age than that.  I’m aware of 1 candidate.  There is an elk vertebrae in the Charleston Museum of Natural History that was recovered from sediments thought to be of early Pleistocene age.  It was found associated with Eremotherium, a species of ground sloth thought to have become extirpated from the region 30,000 years ago.  As far as I know, this specimen has never been radio-carbon dated.  I think it merits dating.  Would the date support the findings of the new study or would it suggest a more complicated history for Pleistocene elk in North America?

Daphne'sdorm

Photo of elk fossils found in South Carolina from the book Additions to the Pleistocene Mammal Faunas of South Carolina, North Carolina, and Georgia by Albert Sanders.  The vertebrae comes from sediments thought to pre-date 15,200 BP.

The DNA evidence from the study make it clear–all North American elk alive today descend from the elk migration across the Bering Landbridge that began about 15,000 years ago.  But this doesn’t rule out the possibility that a now extinct Pleistocene ecomorph of the elk occurred in North America prior to this date.  Both cougars and jaguars lived in North America during the Pleistocene.  DNA evidence proves the North American ecomorphs of these 2 big cats went extinct about 11,000 years ago.  (See: http://markgelbart.wordpress.com/2014/04/11/extinct-pleistocene-ecomorphs-of-the-cougar-puma-concolor-and-the-timber-wolf-canis-lupus/)  All modern individuals of these 2 species descend from populations that lived in eastern South America at the end of the Pleistocene.  It’s not unprecedented for populations of a species to become extirpated, then replaced by other populations of the same species.

Reference:

Meirav, Meiri; et. al.

“Faunal Record Identifies Bering Isthmus Conditions as Constraint to end-Pleistocene Migrations to the New World”

Proceedings of the Royal Society of Biological Sciences 281 (1776) December 2013

Dr. Arthur Gelbart R.I.P.

October 22, 2014

Circumstances force me to take an hiatus from the usual natural history topics of this blog.  Dr. Arthur Gelbart, my father, has passed away.

Arthur Gelbart was born in Buczacz, Poland on Febuary 7, 1930.  He was the son of a shoe store owner, Isadore Gelbart, and his wife Regina.  When the Nazis invaded Poland, the Gelbarts were forced to hide because the Germans were bent on eradicating all Jews.  Isadore paid an Ukranian farmer to hide his family in an hayloft for 2 years.  There, they suffered from frequent want of food and water.  Usually, they were forced to subsist on a daily piece of bread, and the water from boiled potatoes.  During summer their diet was supplemented with dandelion greens, cherries, and cucumbers.  The Gelbarts were liberated by the Russians, but  the Germans counterattacked, and the Gelbarts, along with other refugees, were trapped between the Russians and the Germans before they were able to make an harrowing escape.  My dad always loved to watch WWII movies after this experience because he enjoyed depictions of the allies killing Nazis.

My father and his mother emigrated to New York in 1947, but his parents divorced, and his father stayed behind in Germany with my dad’s brother.  My father missed 5 years of elementary school and English was his second language, yet he was one of the best students at Morris Brown High School in the Bronx, New York.  He earned a swimming scholarship to Rutgers but lost it when the coach caught him smoking cigarettes.  He then attended New York University and worked as a waiter and dance instructor in the Catskills during the summer.  He earned a Fulbright Scholarship that helped pay for him to go to medical school in Germany.  His first year of residence was in Cleveland, Ohio where he met my mother, Audrey Bailey.  They got married and left for Chicago, Illinois for his second year of residency.  I was born there in 1962.  My parents moved to Niles, Ohio shortly thereafter, and my father established a successful private practice in a small town in need of a doctor.  While living in Warren and Niles, my father witnessed the birth of 2 daughters, Susan and Elizabeth.

My father made housecalls for $5.  Today, few, if any doctors, bother making housecalls.  His services as a physician alleviated the suffering of many, and he helped save people’s lives, but in 1975 he was diagnosed with malignant melanoma and was given 6 months to live.  This prompted him to choose an easier career as a staff physician for the University of Georgia.  However, when it became evident  the deadly skin cancer was not going to be a death sentence, he got bored…about the only ailment he ever saw from the students attending UGA was VD. In 1977 he took a job teaching family practice at the Medical College of Georgia and also held the position of Medical Director of the Georgia War Veterans Nursing Home.  He held this position until he retired in 2000.

Daphne'sdorm 014

Dr. Arthur Gelbart and his granddaughter in 2005 when he was still his old cheerful self.

My father enjoyed his retirement.  He liked spending time with his grandchildren, Daphne and Justin.  He frequently went to The Family Y to run “fife miles” and take a sauna and a steam, and in the evenings he liked to watch the same movies and Seinfeld reruns over and over.  In 2008 his health began to slowly decline due to numerous problems.  He died on October 22, 2014. 

I will miss him.

Crocodylians Eat Fruit but may not Disperse the Seeds

October 17, 2014

Scientists know some species of mammals, birds, turtles, and lizards eat fruit and disperse the still viable seeds across the landscape in their scat.  Surprisingly, 13 of the 18 species of crocodylians in the world are known to actively seek and eat fruit also, yet until recently scientists didn’t know whether the seeds they defecated were still viable or not.  Adam Rosenblatt, formerly of Florida International but currently on the Yale faculty, led the first ever study of fruit seed viability in crocodylian crap.  He analyzed the contents of 54 American alligator stomachs from specimens living in the Everglades.  He found fruit seeds in 12 of them.  His alligators ate the fruit of red mangrove, coco plum, and pond apple, but the latter, a type of pawpaw, was by far the most common fruit found in alligator stomachs.  One specimen had 1286 pond apple seeds in its stomach.  Each pond apple has about 6 seeds, so that means this particular alligator ate at least 200 pond apples.

The scientists planted 20 pond apple seeds recovered from alligator stomachs, resulting in a 0% germination rate vs. a 75% germination rate for pond apple seeds that did not go through an alligator’s digestive system.    Alligators often scavenge well-rotted carcasses infected with toxic bacteria, but their strong digestive acids destroy the toxins.  Dr. Rosenblatt belives these strong digestive acids also destroy the viability of pond apple seeds.  Moreover, alligators have a slow metabolic rate, and the seeds can stay in an alligator’s digestive system for months.  Pond apples germinate rapidly and lose viability if not exposed to soil within a short period of time.  Dr. Rosenblatt doesn’t know if the same holds true for other species of fruit and other species of crocodylians, but it appears that American alligators do not help disperse pond apples.

gator fig. 2

Alligator actively seeking out kumquats.

Pond apple (Anona glabra).  Scientists planted pond apple seeds they recovered from alligator stomachs.  None of them germinated compared to the average 75% germination rate of non-digested pond apple seeds.

Pond apples have been introduced to Australia where they have become an invasive species.  Apparently, the native cassowary and feral pigs are facilitating the spread of this species on that continent.  Cassowaries and hogs have quicker digestive systems and weaker stomach acids than those of alligators, and pond apple seeds are capable of surviving the journey through the alimentary canals of these 2 species.  Pond apple seeds are frequently found sprouting in the fresh cassowary and hog dung.

Cassowary and young.  The seeds from pond apples eaten by cassowaries are viable, and this bird is helping spread this invasive species in Australia.

Reference

Rosenblatt, Adam; and Scotty Zara, Michael Heithore, and Frank Mazzetti

“Are Seeds Carried by Crocodylians Viable? A Test of Crocodilian Suochory Hypothesis”

Southeastern Naturalist 13 (3) 2014

Barbary Macaques (Macaca sylvanus) Could Recolonize Southern Europe

October 13, 2014

Periodically, I peruse the abstracts of Quaternary Science Review and look for potential blog topics.  Alas, no recent issues include papers covering the region of my focus–southeastern North America.  However, a recent special issue dedicated to the career of a retiring paleontologist, Alan Turner, was full of fascinating papers about vertebrate paleontology.  (Normally, QSR publishes just an occasional vertebrate paleontology paper.)  One in particular grabbed my attention because it was about an animal I didn’t realize was part of Pleistocene Europe’s fauna–the Barbary macaque.

Barbary macaques.  They are an adaptable animal living in groups of about 30.  They feed upon plant matter and insects–items found in abundance in most temperate habitats.

Barbary macaques originally evolved in Africa about 5 million years ago, and like hominids, they eventually colonized Eurasia.  All Asiatic macaque species are descended from the Barbary macaques that left Africa millions of years ago.  Barbary macaques lived as far north as the British Isles and Germany during especially warm interglacials but became extirpated in Europe during the severest phases of Ice Ages.  They shared the landscape with hippos, narrow-nosed rhinos, straight-tusked elephants, cave bears, leopards, and hyenas.  This cavalcade of animals disappeared from Europe between 34,000 BP-24,000 BP when the landscape was transformed from mostly forests and woodlands to grassy mammoth steppe.  Unlike in North America, there was no thermal enclave where animals could have retreated.  In North America the land mass of Florida, the south Atlantic coastal plain, and the Gulf Coast expanded due to the regression of the ocean, and this provided refuge during Ice Ages for organisms requiring warmer climates.  Genetic studies suggest Ice Age ecological conditions became so unfavorable for Barbary macaques that they became isolated into 2 refugial populations in North Africa.  Following the end of the Ice Age, these populations were able to recolonize lost ground thanks to the improving climate, and they re-united 5000 years ago.  But when the Romans conquered Carthage 2100 years ago, they destroyed extensive areas of North African forests.  This habitat change re-isolated the macaques into fragmented refugial populations again. Climatic and topographical  models suggest  southern Europe could provide habitat for populations of Barbary macaques today.  Human development is probably standing in the way of macaque recolonization of this region.

locator map of England

Map of Europe and North Africa.  Extant populations of Barbary macaques occur in Morocco, Algeria, and Gibraltar.  Climatic models suggest Barbary macaques could survive in southern Europe.  If the climate continues to get warmer, they could potentially recolonize Europe as far north as Germany, as they did during the last interglacial.

There is a population of Barbary macaques living on the island of Gibraltar today.  They are not a remnant population of Pleistocene European macaques.  Instead, sailors brought them here between 711 AD-1492 AD.

References:

Elton, Sarah; and Hannah O’Regan

“Macaques at the Margins: the Biogeography and Extinction of Macaca sylvanus in Europe”

Quaternary Science Review 96 (15) July 2014

Modolo, Lara; Walter Salzburger, and Robert Martin

“Phylogeography of Barbary macaques (Macaca sylvanus) and the Origin of the Gibraltar Colony”

PNAS 102 (22) 2004

Stream Capture Events and the Range of the Robust Redhorse Sucker Fish (Moxostoma robustum)

October 8, 2014

Edward Cope first described the robust redhorse sucker fish in 1870, but it was not rediscovered until 1980, and the newly discovered populations in the Savannah and Pee Dee Rivers were not correctly identified until 1991.  It’s a rare fish listed as endangered by the state of Georgia.  Populations of this species are known from the Savannah, Oconee, and Ocmulgee Rivers in Georgia, and the Pee Dee River in North and South Carolina.  Researchers are in the process of introducing the fish to the Santee River, South Carolina where it is thought to have become extirpated.  The robust redhorse sucker fish lives in rocky pools and the slow runs of small rivers.  It spawns in shallow water with gravel bottoms.  Such environments are now far less common than in days of old because sediment from cleared agricultural and suburban development covers the gravel bottoms, making them unsuitable for spawning sucker fish.  This species spawns in late spring and early summer.  It feeds on freshwater mussels and insects, and the most common species in its present day diet is the invasive Asian clam.  The fish crushes the shells with teeth located in its throat. It grows to over 2 feet long and up to 18 pounds, and it can live for up to 25 years.

Robust Redhorse drawn by Joe Tomelleri

Robust redhorse sucker fish drawn by J. Tomalleri.

There are at least 10 species of redhorse sucker fish in Georgia including the silver redhorse (Moxostoma anisurum), river redhorse (M. carratum), notched redhorse (M. collapsom), black redhorse (M. duquesne), golden redhorse (M. erithrurum), harelip redhorse (M. lacerum), greater jumprock (M. lachner), blactailed redhorse (M. poecilurum), and striped redhorse (M. rupicates).    There may be an additional 3 species not yet given scientific names.  Sucker fish are often labeled as trash fish, but some people know better.  Fish fries featuring sucker fish are held in various locales, and the people who eat them seem to enjoy the fish.  I’ve never had the opportunity to try sucker fish.

The study of redhorse sucker genetics referenced below determined the population of  M. robustum found in the Pee Dee River diverged from the Savannah River population 1.5 million years ago.  There is a considerable distance between these 2 river drainages.  This fact inspires the obvious question: How did this species come to occupy such disparate ranges?  There is a simple explanation.  River drainages are separated by high ridges of land.  Streams that flow into major rivers often erode backwards into the ridges and occasionally erode into the stream of another river system.  These backward flowing streams then capture the other stream, causing it to reverse and flow into the other river drainage.  This is how fish species spread into different river drainages.  The Savannah River drainage is too far away from the Pee Dee River to have ever shared a stream capture event.  However, the robust redhorse sucker fish formerly occurred in the river drainage between these 2 distant river systems.  The Santee River drainage served as a conduit between the 2.  Various stream capture events between the Savannah and Santee and between the Santee and Pee Dee facilitated the exchange of many species of fish.

South Carolina Lakes and Rivers Map

Map of South Carolina river systems.  A series of stream capture events in the Southern Appalachians likely led to the colonization of the robust redhorse sucker fish and many other species of fish into adjacent river systems.  Populations of this species have been found in the Savannah river system and the Pee Dee river system.  Note the considerable distance.  The intervening population has become extinct.

Effects of stream capture on species-richness of adjacent drainage basins based on dispersal, vicariance, and extinction

Figure showing how stream capture events can occur and result in the spread of a fish species into another river system.

Streams erode backwards more rapidly in overgrazed landscapes.  Pleistocene megafauna overgrazed many areas, thus increasing the frequency of stream capture events in the past.

References:

Darden, T.L.; and C.M. Tarpey

“Genetic Characteristics of the Savannah and Pee Dee River Populations of Robust Redhorse (Moxostoma robustum) with Conservation Implications”

Copeia 2014

Matthews, William

Patterns in Freshwater Fish Ecology

Springer 1998

 

The Evolution of Soccer to Rugby to Football

October 3, 2014

On this blog I infrequently voice my fantasy of traveling in a time tunnel to Georgia as it was 36,000 years ago.  Here, I establish a secure homestead and enjoy living off the land in a wilderness untouched by man.  I bring as many modern conveniences back in time with me as possible because I’m not a masochist who believes in unnecessary suffering.  In fact I’ve even proposed bringing a few voluptuous models with me  (it’s just a fantasy afterall). As long as I had a sturdy house, electrical power, plentiful food and alcohol, and a naked woman’s backside in my vicinity; there would not be much about this modern world that I would miss.  I could look out the window and see a saber-tooth or a bear and be entertained to my satisfaction, though I’d bring a library of books, music cds, and dvds with me.  About the only thing from this modern world I would miss that I couldn’t bring back with me would be college football–easily the most exciting spectator sport ever invented.

Modern American football evolved from an ancient sport that may have originated thousands of years ago.  I wouldn’t be surprised if stone-aged tribes kicked and batted the inflated bladder of a wild boar around.  It seems natural that some playful participant would have suggested a friendly test of each tribe’s strength.  Could his tribe push the object past the other tribe?  There is no evidence of this, probably because football-like games predate written history.  The Romans played a game called harpastum.  From the ancient descriptions harpastum seems very similar to rugby, and the Romans copied this game from one played by the Greeks.  Who did the Greeks learn the game from?

The first written record of the word, “football,” dates to 1180 in England.  The English royalty outlawed “football” and “handball” between 1314-1667.  These early ordinances already differentiated games that included rules favoring advancing the ball with the foot vs. those favoring carrying the ball.  Whole towns played against each other in these brutal contests and I doubt the laws were enforceable–officials couldn’t imprison the entire town. 

By the 19th century schoolboys often played soccer at recess.  According to legend, William Ellis, a student attending Rugby in 1823, had had enough of scoreless ties.  Before the bell rang ending recess, he picked up the ball and ran it into the goal.  This account is probably a myth, though the game as played in Rugby did change during this time period to one that allowed carrying the ball.  In reality rules varied depending on local preferences with some schools or regions favoring more handling of the ball, while others allowed less.  Handling the ball in soccer wasn’t completely outlawed until 1863.  Those favoring what’s known as rugby today didn’t codify their rules until 1871.

In the early 19th century America’s school kids played a game mostly resembling soccer, but the rules they used did allow some handling of the ball.  Players were allowed to bat the ball, and if they caught it, they were allowed a free kick on goal, not unlike modern Australian rules football.  Canadians introduced rugby to the United States in 1871, and it quickly became much more popular than soccer.  However, Americans thought scrums were a boring part of the game.  In rugby when a player is tackled, both teams have to fight for possession of the ball at the spot of the tackle.   The ball can stay hidden in the pile of men for a long time and the flow of the game is interrupted.  Walter Camp, a player/coach at Yale University, proposed changing the rule so that the team retained possession of the ball after the tackle.  Following this rule change, teams with the lead and the ball simply took a knee, necessitating another rule change also invented by Walter Camp.  Teams were given 3 downs to make 5 yards.  This rule lasted from 1880-1912 when it was changed to 4 downs to make 10 yards.  Canadian football still uses the 3 downs to make 5 yards innovation.  Walter Camp also invented the rule that the quarterback takes the snap from the center and hands off the ball to another player.  In the early days the center rolled the ball back with his heel.  But in 1891 the between-the-legs snap was invented.

scrum1 300x184 Talking Rugby: The problems with the scrum

Rugby scrum.  Americans thought scrums were a boring part of the game so they invented the new line of scrimmage instead: the downed player’s team retains possession. This rule change caused the 2 sports to diverge.

Artist’s depiction of an early American football game.  Before the legalization of the forward pass and other rule changes that opened up the game, these contests were far more dangerous than modern day football.

Early American football was an even more dangerous sport than it is today.  Before the forward pass was legalized, the best strategy was to carry the ball straight ahead using masses of blockers lined up in a v-formation or otherwise bunched together.  All of the blockers would converge on 1 point of the defensive line, so that 4 or 5 players were slamming into 1 defender.  Even outside runs were a little used strategy because the concept of hashmarks hadn’t been established yet, and if the ball carier was forced out of bounds, the center had to snap the ball from the sidelines, greatly constricting the offense.  Early football was a defensive game with teams often punting on first down.  Field goals had a greater point value than touchdowns.  The team with the better kicker usually won because the better punter set his team up for more field goals or dropkicks by changing field position.  Field goals were reduced from 4 points to 3 points in 1909, and touchdowns were increased to 6 points in 1912, finally making touchdowns more valuable.

The high numbers of deaths in the early years of football led to rule changes to open up the game.  In 1906 lineman were no longer allowed to lineup in bunched formations, and the forward pass was legalized, despite the opposition of Walter Camp who coached powerful teams, specializing in mass momentum plays.  Nevertheless, teams didn’t often use the pass because a) the quarterback had to be 5 yards behind the line of scrimmage before he threw a pass and he was not allowed to run with the ball, b) a team lost possession if the pass was incomplete, c) it was illegal to pass the ball over the goal line, and d) the ball was made for kicking not throwing.  In 1912 the rule was changed so that an incomplete pass did not result in a turnover.  Some teams began to pass the ball more often after this, but the passing game didn’t really get going until 1933 when the ball was changed to better suit throwing it rather than kicking it.  Other restrictive rules were eliminated in 1933 as well.  Hashmarks were also introduced in this year, encouraging teams to call outside runs more often.

Audible signals predate the huddle.  The huddle was invented by a team of deaf football players  in 1892 but was not widely used until 1921.  Before this, teams lined up rapidly and called the plays at the line of scrimmage–much like modern day no huddle offenses.  Here’s a link to the earliest footage of a college football game.  It’s the 1903 game between Yale and Princeton, filmed by Thomas Edison https://www.youtube.com/watch?v=uERnf4jHe7s.

In the early days football, like soccer, only allowed 3 substitutions and once a player left the game, he could not return.  Players had to play offense and defense, and helmets were optional until 1939.  From 1941-1952 college teams were allowed unlimited substitutions.  The rule changed back to one platoon until 1964 when unlimited substitutions were once again allowed.  The NFL legalized unlimited substitutions in 1950.  Modern day substitution allows for more specialization.   Modern players are bigger, stronger, and faster, but these old school players must have had the edge in stamina.

I like college football more than pro.  In the NFL it is theoretically possible that a team with a 7-9 record could make the playoffs and win the Super Bowl.  This diminishes the value of each game, making them less exciting.  In college football 1 or 2 losses can be fatal to a team’s national championship hopes.  But even if this happens, rivalry games are still important and stoke more interest than late season NFL games which often have uninteresting matchups such as a 2-11 team going up against an 8-5 team or worse yet a 3-10 vs a 4-9.

The Georgia Bulldogs are my favorite team.  Todd Gurley is my favorite active player.

gurley-soars-oklahoma-drill

Todd Gurley leaping for a touchdown.  Beating Georgia Tech never gets old.

Reference:

Revsine, Dave

The Opening Kickoff

Lyons Press 2014

Mastodons ate Wild Squash

September 28, 2014

The scent of burning leaves and baking squash always reminds me of autumn.  I love the pulpy rich flavor of an orange-fleshed winter squash, dripping with melted butter and brown sugar.  Mastodons enjoyed squash too but ate them without the additional condiments.  The species of wild squash eaten by mastodons had a bitter rind.  Mastodons avoided eating this part of the squash by stepping  on the rind to break open the squash.  The mastodon would then pick up the nutritious seeds and pulp with its trunk and place the edible matter in its mouth.  The mastodon would later defecate the still viable seeds and spread the spawn of squash all over the landscape.  We know this because mastodon coprolites containing squash seeds (but not rinds) were recovered from the Aucilla River located in northwestern Florida.  Scientists were unable to identify the exact species of squash the mastodons ate.  The morphology of the seeds differs from all known species and may perhaps be either an extinct species or an extinct variety of an extant species.  Wild squash no longer occurs in this region of Florida, however, there are 2 species that live in south Florida.

The Okeechobee gourd (Cucurbita okeechobensis) was formerly common in an environment known as pond apple forests that grew south of Lake Okeechobee.  Pond apples (Anona glabra) are a species of pawpaw–a fruit mastodons surely also consumed.  The conversion of pond apple forests to agriculture destroyed 95% of this habitat, and the Okeechobee gourd is now listed as an endangered species.  William Bartram found this species growing along the St. John’s River in 1774, but this population wasn’t rediscovered until 1993.  The presence of this disjunct population is evidence the Okeechobee gourd was formerly more widespread.  The extinction of the mastodons as a dispersal agent probably explains the limited distributions of the Okeechobee gourd and other species of wild squash.

File:Cucurbita okeechob okeechob.jpg

The Okeechobee  gourd (Cucurbita okeechobensis) .  This species once had a greater distribution.  Seeds of an unknown species similar to this have been found in mastodon coprolites.

The Okeechobee gourd has an interesting ecological niche.  It prefers growing by lakes and rivers with fluctuating water levels. High water levels kill competing plant species.  Then during droughts, water levels recede, leaving bare soil where the Okeechobee gourd can sprout before having to compete with other pioneer species.  They also thrive on alligator nests because the great reptiles clear their composting nests of competing plants.  The vines of the Okeechobee gourd grow on pond apple, willow, cypress, buttonbush, elderberry, and common reed.  Marsh rabbits gnaw through the squash rinds and help distribute the seeds, but they are an inferior dispersal agent compared to mastodons.

The other species of wild squash found in south Florida is not native but was brought from South America by Indians thousands of years ago. Native Americans began cultivating squash at least 8000 years ago, long before they cultivated corn and beans.  The word, squash, is derived from the Naragansett Indian word askutasquash, literally meaning green-thing-eaten-raw, though I’m sure they also cooked this vegetable.  The Naragansetts lived in what today is Rhode Island and Massachusetts.  The variety of C. moschata found growing wild in south Florida is known as the “Seminole pumpkin.”  The Seminoles are descendents of Creek refugees who fled to the Everglades to escape the U.S. Army.  The Creeks brought this variety with them.  The Seminoles set up their habitations on oak hammocks, the islands of hardwood trees found in the Everglades marshes.  They cultivated squash by girdling oak trees and planting the squash seeds at the base of the dead trees.  The leafless trees allowed for sunny gardens.  The squash vines grew up the dead tree trunks, and the Indians harvested the fruit by climbing into the tree tops.  Trees on the outskirts of the garden were left ungirdled, and these provided a windbreak.  The Seminoles also grew Okeechobee gourds.  Though inedible, dried Okeechobee gourds served as ceremonial rattles.

 

Seminole pumpkins (Cucurbita moschata).  This is the exact same species as the butternut squash commonly sold in grocery stores.

There are 27 species of squash in the Cucurbita genus.  Although many wild species sport the common name of gourd, they aren’t true gourds.  All squashes belong to the genus Cucurbita, while true gourds found in Africa belong the the Lagenaria genus.  Both genuses are in the same subfamily, so they are related.  The Cucurbita genus evolved from a common ancestor of Sechium edule–the chayote squash which is not a true squash but rather closely related to an ancestor of true squashes.

Many of the cultivated squash species commonly consumed by humans include many different varieties that differ surprisingly in appearance.  C. pepo includes zucchini, yellow crookneck squash, delicata squash, acorn squash, and field pumpkins. C. maxima includes giant pumpkins, Hubbard squash, Kabocha squash, and banana squash.  C. argyrosperma includes cushaw squash.  C. moschata includes butternut squash and Seminole pumpkins.  To add to the confusion, C. pepo can hybridize with C. moschata and C. argyrosperma; and C. maxima can hybridize with C. moschata.  The wild stinking gourd (C. foettidisima) can hybridize with all the edible species.  Four species of wild squash are perennials with strong roots, while the rest, including all the cultivated species, are annuals.

Daphne'sdorm 013

The top squash in this photo is a butternut squash I grew from a seed I obtained from one I bought in a grocery store. The bottom squash is a delicata squash I purchased at a farmer’s market.  I tried growing delicata squash from seeds but the squash bugs destroyed them.  Both are known as winter squash but they are actually 2 different species.  Butternut squash is (C. moschata), the same species as the Seminole pumpkin.  Delicata squash is the same species as summer squash–C. pepo, though it tastes quite different.  

Cucurbita pepo collage 1.png

Field pumpkins, yellow squash, zucchini, pattypan squash, and acorn squash are all the same species–Cucurbita pepo.

Giant pumpkins, Hubbard squash, buttercup squash, Kabocha squash, and banana squash are all the same species–Cucurbita maxima.  This specimen almost weighs a ton. 

 File:Cucurbita argyrosperma 2.jpg

Most canned pumpkin is actually made from cushaw squash–Cucurbita argyrosperma.

My favorite way to cook summer squash is to quarter them, put them in a baking pan well greased with olive oil, season with salt and pepper, and roast at 400 F for 30 minutes.  Then, I toss them with balsamic vinegar or lemon juice.  This brings out the flavor better than any other method.  I also like to slice them into rounds and sautee them in a pan at high heat till brown and season with salt, pepper, and chopped nuts.  Cooking winter squash is even more simple.  I just split them in half and bake in a pan of water at 350 F till tender and serve with plenty of butter and brown sugar.  Baked butternut squash pulp makes a far better pie than the watery “pumpkin pie” filling sold in cans.

I’ve had great success growing zucchini.  One year, I harvested over 100.  The next year, I decided not to add chemical fertilizer to the soil because I was being cheap.  I harvested 0.  I’ve had a harder time growing winter squash in my garden.  I did successfully grow cushaw squash once.  One summer, I harvested half a bushel of butternut squash that I didn’t even plant on purpose–they germinated from compost I added to my garden.

Reference:

http://www.fws.gov/verobeach/MSRPPDFs/Okeechobee.PDF

Megafauna Geophagy

September 24, 2014

Sometimes animals eat dirt.  The official scientific word for dirt-eating is geophagy.  Animals eat dirt for 2 reasons: to obtain minerals otherwise lacking in their diet and to prevent toxins from being absorbed into their bloodstream.  Over 200 species of animals including deer, bison, elephants, bats, primates, and birds are known to eat dirt.  Minerals aren’t evenly distributed in the soil, and plants are often deficient in certain nutrients because of  poor soil, as gardeners well know.  Animals living in these environments actively seek out soils rich in sodium, calcium, or iron.  These locations are known as mineral licks because ungulates literally “lick” the soil.

Elephants enter caves to access salt.  They grind the salt off the walls with their tusks.

Animals eat clay for a different reason.  The negatively charged clay particles bind with positively charged toxins ingested from plants high in alkaloids, preventing absorption into the blood stream.  In 1 experiment James Gilardi fed parrots quinidin, a toxin.  He made clay available to some of the parrots but not to others.  The parrots given the opportunity to eat clay had 60% less quinidine in their blood than the other parrots.  Pregnant fruit bats also eat considerable quantities of clay because they eat twice as much fruit as they normally do, and therefore ingest greater quantities of toxins.

Chimpanzee licking dirt off his (her?) fingers.  The dirt is eaten before or after the ape consumes plants containing anti-malarial compounds.  It counteracts the toxins.  This is amazing.  It’s like the chimp is creating its own pharmaceutical.

Macaws & other Parrots Eat Clay

Macaws at a clay lick.

The Diagnostics and Statistics Manual used by psychiatrists lists geophagy in humans as a mental disorder.  Psychiatrists are wrong.  Humans eat dirt for the same reasons animals do.  Eating dirt is common among women in Africa who suffer from diets low in calcium.  Eating clay reduces toxins hazardous to the fetus, and it may alleviate morning sickness.  The clay they use is often harvested from termite mounds.  The termites bring up clay from deep underground where it is free from harmful micro-organisms and parasites.  Kaopectate and Pepto-Bismol, 2 popular over the counter medications, formerly contained kaolin clay.   Kaolin clay has been replaced with synthetic ingredients that mimic the same properties.

Pepto-Bismol formerly included kaolin clay as an ingredient but it has been replaced with a synthetic substance.

Georgia is rich in clay soils, especially along the kaolin clay belt just south of the fall line.  During the Pleistocene there were probably many clay licks that attracted mastodons, ground sloths, bison, horses, tapirs, etc.  The Great Buffalo Lick in Oglethorpe County (See: http://markgelbart.wordpress.com/2011/05/21/my-expedition-to-kettle-creek-battlefield-the-little-kettle-creek-fossil-site-and-the-great-buffalo-lick/)  was the last known location in Georgia where megafauna herds were known to lick the soil.  The areas around the licks were quite altered.  The animals licked these spots into gullies, and the general vicinity was composed of bare soil and a few sun-loving trees.  White clay-colored fecal matter littered the general area.  These licks are just another lost natural community once common but no longer extant in the region.

Reference:

Starks, Phil; and Brittany Slabach

“Would you like some dirt with that?”

Scientific American 306 (6) 2012

 

Changes in Vegetation Patterns Following Megafauna Extinctions

September 19, 2014

C.N. Johnson of James Cook University in Australia shares my fascination with how extinct megafauna influenced past ecosystems.  Not long ago, he published a paper about my favorite discussion topic entitled “Ecological Consequences  of Late Quaternary Megafauna Extinctions.”  He believes the extinctions of so many large mammal species led to 3 major changes in the environment.

1. The replacement of open woodlands and diverse habitat mosaics created by megafauna foraging with uniform closed canopy forests and zonal vegetation.

2. An increase in flammable plant material and thus an increased frequency of fire intervals because the plant biomass was no longer being eaten.

3. The decline of co-evolved plants such as large-seeded fruits dependent upon distribution by dung transport, and plants that put much of their energy into growing defensive thorns to deter herbivory.

Dr. Johnson relates an interesting hypothesis as to how Pleistocene ecosystems responded to megafauna foraging.  The feeding and trampling behavior of mammoths, bison, horses, and ground sloths suppressed woody regeneration.  Scrubby thickets dominated by thorny plants grew in place of highly shaded forests.  And patches of natural pastures grazed into short grass lawns impeded the fires that could potentially burn thickets.  When the thorny vegetation grew thick enough, megaherbivores avoided these locations, allowing shade intolerant species such as herbs, oaks, and hazelnuts to sprout and grow.  The widely spaced oaks and other deciduous trees would eventually shade out the thorny thickets. The megafauna would return to suppress the regeneration of the woodland as the trees aged and died, and the cycle would begin anew.  I can guess who the players were in this scenario here in southeastern North America.  Thorny greenbrier and blackberry vines along with hawthorne grew in areas temporarily left ungrazed.  The thick growth discouraged most animals larger than a rabbit from penetrating this space.  Sun-loving oaks, hazelnuts, persimmon and plum popped up.  Perhaps not coincidentally, hazelnut has a lesser distribution in North America now than it did during the Pleistocene.  A hazelnut was extracted from a mastodon coprolite found in Florida.  Hazelnuts no longer occur in Florida’s wild.

Thorny scrub habitat in south Texas.  The sharp spines of the yucca  could theoretically deter a species of large mammal from chewing on the tree or trampling it.  When the tree grows larger and older, it will shade out the spiny plants that originally protected it.

American Hazelnut Tree

American hazelnut (Corylus americana).  This species was more widespread and common in the south during the Pleistocene because the megafauna suppressed tall forest regeneration.  Hazelnut trees prefer sunny conditions and can’t grow in shade.

Hazelnut_CorylusLarge.jpg

Photo of the actual hazelnut extracted from a Florida mastodon coprolite dated to ~14,000 calender years BP.  Hazelnut no longer occurs in Florida.

Some pollen studies in Europe dating to the last interglacial, when megafauna was abundant and climate similar to that of today prevailed, contradict the above hypothesis.  Shady closed canopy forests dominated much of northern Europe.  However, other pollen studies from evidence collected in river bottomlands do show evidence of higher populations  of diverse sun-loving plant species, and this evidence is associated with  the abundant remains of dung beetles. This suggests patchy environments influenced by megafauna activities did occur near rivers.  This makes sense: large herds of megafauna likely occurred where water was an easily accessible resource.  If we were to go back in time and search for megafauna in Georgia, our best bet would be to travel along river corridors.  Large mammals were probably scarce or even absent in locations far from water.  The ancient environment of the southeast likely consisted of a mosaic of small and large grasslands, open woodlands, closed canopy forests away from where megafauna congregated, and thorny thickets.

The pollen record of southeastern North America does consistently show a large increase in shade tolerant beech approximately correlated with the timing of megafauna extinction.  This suggests forests became more close canopied when large mammals became extinct.

One study discussed in Dr. Johnson’s paper proposed that the extinct Irish elk (Megaloceros giganteus), the largest deer known to science, converted Ireland’s scrub habitat into grassland.  Megaloceros recolonized Ireland ~16,000 years ago when glaciers retreated and the land became habitable.  Willow scrub dominated the landscape initially, but Megaloceros favored browsing on shrubs for the phosphorus content.  Juniper and crowberry replaced the willow, then Ireland became mostly grassland because Megaloceros suppressed the growth of shrubs.  After Megaloceros became extinct here, willow scrub again became the primary type of environment in Ireland.

Scale drawing comparing the extinct Irish elk with a man.  This animal may have transformed Ireland from willow scrub to grassland about 16,000 years ago.

Reference:

Johnson, C.N.

“Ecological Consequences  of Late Quaternary Megafauna Extinctions.” 

Proceedings of the Royal Society of Biological Sciences 2009


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