Archive for the ‘Uncategorized’ Category

The Ancient Rivalry Between Cats and Dogs

January 18, 2018

The PBS documentary series, Nature, recently featured a 2 part episode about cats.  During the first episode the narrator claimed cats caused the extinction of at least 40 species of dogs after the felines colonized North America.  I knew there had to be a journal article behind this claim, so I googled “cats caused extinction of 40 dog species.”  I found the paper (referenced below) and also discovered 90% of media outlets misreported the conclusions of the study.  Cats did contribute to the extinction of many dog species, but competition with other dog species and the extinct carnivores known as Barbourofelidae were also responsible for the extinctions.

Dogs originally evolved in North America, while cats originated in Asia.  About 40 million years ago a land bridge began to periodically emerge across the Bering Strait, allowing cats and dogs to colonize each other’s continent of origin.  When cats first colonized North America there were 3 subfamilies of dogs–the Hesperocyoninae, the Borophaginae (or bone-eating dogs), and the Caninae.  The Hesperocyoninae and the Borophaginae are extinct.  All living species of dogs, jackals, wolves, and foxes belong to the Caninae subfamily.

The scientists who authored the below referenced paper collected data about climate change, and the fossil occurrences of predators including Felidae (cats), Amphicyonidae (the extinct bear-dogs), Barbourofelidae, Nimravidae (false saber-tooths), and the Ursidae (true bears).  They used statistics to determine whether climate change or competition with other carnivores caused the extinction of some species of dogs.  They concluded the extinction of 1 subfamily of dogs, the Hesperocyoninae, was caused by competition with another subfamily of dogs, the Borophaginae.  Cooler climate may have contributed to the extinction of some Borophaginae species 15 million years ago.  Finally, competition with Barbourofelidae, cats, and the surviving subfamily of dogs (the caninae) drove the remaining species of Borophaginae into extinction.

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The Barbourofelidae are an extinct group of carnivores distantly related to cats but different enough to be classified as a separate family.

The species of dogs that did become extinct were often cat-like in build and probably occupied ecological niches preferred by cats.  So cats were just better than these cat-like canids at surviving in these niches.  But the Caninae were also better adapted to survive in the constantly evolving environment.  The cat and dog species that emerged from this age-old competition have achieved a kind of stalemate.  Representatives of both naturally occur on every continent but Antarctica and Australia.  (Dingos were brought to Australia by man.)  1 species of each–Canis familiaris and Felis catus —live in our homes and compete for our affections today.

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References:

Silvestri, D.; A. Antonelli, N. Salamin, and T. Quentas

“The Role of Clade Competition in the Diversification of North American Canids”

PNAS 112 (28) 2015

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R.D. Lawrence–Wildlife Writer

November 8, 2017

I enjoy deciphering articles published in scientific journals and translating them into language a layman can understand.  I learned how to do this because of my long fascination with Pleistocene ecology.  Information about Pleistocene ecology almost entirely comes from scientific journal articles, and I found the language in these publications can be unnecessarily complex and oftentimes the writing is just bad.  I had to learn how to interpret them.  Some scientists are good writers, but others are not.  R.D. Lawrence (1921-2003) was a writer who felt the same way I do about language in scientific journals.  At 1 point in his life he was studying to be a biologist.  He wrote a thesis about stickleback fish, and his professor told him it was good, but he wanted him to rewrite it in the language used by scientific journals instead of the easy to understand language Mr. Lawrence had used.  He rejected this “babblespeak” and dropped out of school.  He later wrote 36 books about Canadian wildlife and won 7 awards.

The late R.D. Lawrence relaxing at home with his pet raccoon.

R.D. Lawrence was born in Spain to a Spanish mother and an English journalist who worked for Reuters.  At the age of 14 he was separated from his family during the Spanish Civil War, and he joined the side fighting against the fascists.  (Ironically, his brother joined the fascists.)  Though just a teenager, he led 1 military attack in the sewers against the fascists.  Eventually, he escaped to southeastern France and was later reunited with his family in England.  He fought for Great Britain during World War II.  He was at Dunkirk, rode a tank in North Africa, and was severely wounded during the D-Day invasion.  His injuries ended his military career.  He moved to Canada and worked as a journalist, while studying nature in his spare time.  He gathered enough material so that he was able to start getting his books about Canadian wildlife published.  Recently, I’ve read 3 of his books.

Mr. Lawrence and his wife bought some land in the wilderness of Ontario during 1962.  Here, they built a cabin where they spent weekends.  (He still worked as a journalist during the week.)  He bought the land before most of Ontario was logged over and converted into suburbs, so much of the wildlife was naïve and not particularly afraid of people.  He wrote about his experiences at this cabin in his book, The Place in the Forest.  The semi-tame animals frequenting his cabin yard included red squirrels, fox squirrels, flying squirrels, white-footed mice, snowshoe hares, and birds.  Bird seed and table scraps encouraged the creatures of the forest to hang around the cabin, and if the door was left open, they would enter the cabin and help themselves.  Mr. Lawrence and his wife adopted 2 orphaned raccoon kits and after they were grown and freed, they often returned and joined the feast.  Mr. Lawrence also wrote about some of the less tame inhabitants in the local wilderness–beavers, deer, wolves, black bears, and birds of prey.  He didn’t let worms and insects go unnoticed either.  My favorite chapter relates his encounter with a bald-faced hornet’s nest when he was climbing a tree to photograph a hawk’s nest on another nearby tree.

Mr. Lawrence’s wife died of a brain aneurism at a quite young age, prompting him to move to British Columbia where he decided to buy a boat and travel up the Pacific coast from Vancouver to southern Alaska by himself.  He wrote about this experience in his book, Voyage of the Stella.  When he fished for salmon to eat, he often caught weird species of fish–wolf fish, Pacific lancet fish, barrel eyes, and dogfish. He fed these to the killer whales that occasionally swam near his boat, and he even dove in the water with them while wearing his scuba gear.  The killer whales never bothered him, but he once had to fend off a blue shark.  On his journey he also encountered pods of Dall’s porpoises and a pair of whale sharks.  He refueled his boat at the Indian villages that dotted the coast.  Most of the Indians were friendly, but 1 drunk tried to hit him over the head with a ketchup bottle while he was trying to eat supper at a restaurant. The brave war veteran floored the Indian with an open palm blow to the forehead.

Mr. Lawrence demonstrated even more courage in his next book, The Ghost Walker.  He spent 8 months in a wilderness cabin located in a remote area of British Columbia that was 60 miles from the nearest town, and the only feasible connection to civilization was an hazardous canoe ride down a river.  He used this makeshift cabin as an home base for tracking a large male cougar.  He gained the cougar’s trust, and the big cat let the man follow him around.  Mr. Lawrence experienced several dangerous situations, aside from trusting the cougar not to turn around and eat him.  During a blizzard, Mr. Lawrence sought shelter in a creekside cave but found himself staring eye-to-eye with an hibernating grizzly bear.  Mr. Lawrence popped out of the cave like a “champagne cork” and fled, dropping his backpack which the angry bear tore to shreds. On another occasion he slipped down an icy slope, hit a tree, and sustained a concussion.  He administered his own first aid.  He often tracked the cougar after sunset, walking in the dark woods by himself for hours.  He was 1 brave soul.

I have 1 criticism of Mr. Lawrence.  He imagined he had established ESP connections with a cougar and a killer whale.  There is no rational scientific basis for his belief.  I’m sure it was his imagination, not an ESP connection.  He was just lucky the animals he “communed” with didn’t decide to attack and eat him.

 

No Need for Males

September 23, 2017

I probably read the novels At the Earth’s Core and Pellucidar about 20 times when I was between the ages of 10 and 15.  They were written by Edgar Rice Burroughs, creator of Tarzan, who also wrote a crossover novel entitled Tarzan at the Earth’s Core. The world Burroughs created fascinated me.  An old scientist, accompanied by a classic American hero, builds a drilling machine that takes them to the center of the earth where they find a land of dinosaurs, pre-historic mammals, friendly natives, and barbaric ape-like cavemen known as the Sagoths.  The novels are full of chivalrous nonsense.  After the hero, David Innes, saves a beautiful native woman from being ravaged by a Sagoth he makes a faux pas–according to the custom among the natives of this world, a saved woman was to be embraced and kissed and made a mate or freed.  Innes didn’t know he was supposed to place his hand over her head to symbolize her freedom, otherwise she was considered his slave.  It takes him a while to realize his mistake and right his wrong.  Later, he has to save her again from a race of intelligent dinosaurs that rule this world.  This race of all female dinosaurs, known as the Mahars, raise humans like livestock.  Whenever they want something to eat, they hypnotize, then eat their human chattel.

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Illustration of human being hypnotized by intelligent parthenogenetic dinosaur in Edgar Rice Burroughs’ At the Earth’s Core.  In this fantasy novel the intelligent all female dinosaurs enslaved and fed upon humans until they were routed by the hero from the earth’s surface.

In Burroughs’s novel the Mahars used science and technology to eliminate the need for males, but in the real world evolution has eliminated males in 80 species of reptiles, amphibians, and fish.  Organisms that produce viable eggs without mating are known as parthenogenetic.  Species that are all female have a couple of advantages over species that need to mate.  They can reproduce when their population is low, and energy is not wasted on individuals that produce no eggs.  Most species are not parthenogenetic because in most cases the disadvantages outweigh the advantages.  Parthenogenetic species can suffer low genetic variability leading to an increase in harmful mutations.

The New Mexican whiptail lizard (Cnemidophorus neomexicanus) is an example of an all female parthenogenetic species.  The New Mexican whiptail lizard is an hybridized cross between the little striped whiptail lizard (C. ornatus) and the western whiptail lizard (C. tigris).  The New Mexican whiptail lizard produces viable eggs that all hatch to become female clones.  New lineages are created and genetic variability is established every time a western whiptail mates with a little striped whiptail.  New Mexican whiptails engage in lesbian sex.  This, of course, doesn’t fertilize the eggs, but lesbian whiptails do produce more viable eggs, probably because the sex stimulates hormone production.

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New Mexican whiptail lizards are all female clones.

Some species of vertebrates are facultive parthenogenetic species.  They normally mate with individuals of the opposite sex, but when populations are low can produce viable eggs without mating.  Komodo dragons, boa constrictors, and some species of sharks are able to switch from sexual breeding to asexual reproduction.  The offspring can then mate normally when they come into contact with males.  Other species are considered accidental parthenogenetic species.  They produce viable eggs without mating on very rare occasions.  Parthenogenetic cases have been reported for chickens, turkeys, and pigeons.

Many species of plants and invertebrates are parthenogenetic.  Unlike vertebrate parthenogenetic species which produce all females, invertebrates and plants can produce offspring that are all female, all male, or female and male.

 

Meat Eater

June 28, 2017

Steven Rinella hosts the television series Meat Eater, an hunting show airing on the Outdoor Channel every Monday at 8:00 pm.  He hunts for the right reason.  Many hunters kill animals so they can hang a trophy on the wall.  Others (more than any pro-hunting organization would ever admit) simply like to kill animals for the hell of it.  On an episode of one of Anthony Bourdain’s television series the host went hunting with a bunch of duck hunters who didn’t like the taste of duck.  Mr. Bourdain, an accomplished chef, changed their minds when he showed them how to correctly cook the birds.  But still, I don’t get it.  Why did all those men go duck hunting, if they didn’t like to eat duck?  Mr. Rinella is not like that at all.  Most Meat Eater episodes show him cooking and eating whatever animal he killed for that week’s show.

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Steve Rinella, host of the tv series Meat Eater.

Mr. Rinella first published an interesting and well written book about 10 years ago entitled The Scavenger’s Guide to Haute Cuisine.  The book is about his year long quest to produce a 45 course 3 day feast of recipes from a century old cookbook authored by the famous French chef Auguste Escoffier.  Many of the recipes used animals once popular but not commonly consumed today.  He caught stingray off the Atlantic Coast, trapped house sparrows and pigeons in the inner city, hunted wild pig in California, and helped an eel fisherman gather eels from his weir in Delaware.  He discovered he no longer enjoyed gigging for bullfrogs in Michigan.  Although this was an activity he enjoyed as a child, he admitted it grossed him out as an adult.  The frogs he killed for the feast would be his last because he decided to retire from frog-gigging.  Of course, he hunted bear, elk, mountain goat, and pronghorn out west–the main guest stars of his current television series.

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Mr. Rinella’s book is interesting and well-written.

My favorite chapter in the book was about his trip to coastal Alaska when he had the opportunity to fish for halibut.  I know I will never have a chance to visit this region and see all that wilderness and rich marine life.  By reading about his experience, I at least enjoyed some vicarious satisfaction.

Ironically, Mr. Rinella’s girlfriend at the time was a Jewish vegetarian.  He successfully converted her into a fish and shellfish eater but his feast of headcheese, pigeon cooked in pronghorn bladder, crayfish mousse, and 11 other old-fashioned dishes made her sick.  Most of the dishes he served at his Thanksgiving weekend feast of 45 courses were hits but there were misses as well.  I suppose his guests were friends close enough to give him their honest opinions.

I own a copy of Escoffier’s cookbook, but I rarely use it.  The book has over a thousand recipes, mostly consisting of various fancy ways to decorate a plate.  I am more of a blue plate special kind of cook and eater–hamburger steak and gravy, mashed potatoes, chili con carne, smothered pork chops, chicken and sausage jambalaya, stuffed cabbage, Greek salad, pumpkin pie, blueberry cobbler, etc.  Good food makes presentation irrelevant.  Escoffier doesn’t inspire me, but I’m glad it inspired Mr. Rinella to take on this project and write a book about it.  I concede Escoffier’s book is a decent primer on cooking technique.  It has helped Mr. Rinella become a really good cook.  Just look at all these delicious recipes posted on his website.

http://www.themeateater.com/section/recipe/

Mr. Rinella shares my disdain for the euphemism of the word, harvest, as a substitute for kill.  It always irks me when hunters say they are harvesting an animal.  Harvesting means a person is picking an apple or an ear of corn.  If an animal isn’t killed instantly, I’m sure the bullet or arrow piercing its nerves and flesh hurts a lot.  Hunting is killing, not harvesting.  Hunters who use the word, harvest, are dishonestly sanitizing what they do.  I’ve taken some flack for my opinion about this, but at least 1 person agrees with me.

 

Pygmy Sperm Whales of the Pliocene

May 14, 2017

The transition between the Pliocene and the Pleistocene about 2 million years ago was  marked by a major marine extinction event.  By contrast there was far less faunal turnover on land.  Many species of whales that no longer exist swam in Pliocene oceans.  Paleontologists recently analyzed fossil whale ear bones excavated from sites in Florida and North Carolina and determined at least 2 morphotypes of pygmy sperm whales occurred in the Atlantic Ocean during the Pliocene.  These specimens may represent different species or size variations within a single species.  Scientists can’t make a certain determination based on just the ear bones.  Extant bottle-nosed dolphins ( Tursiops truncatus ) occur as 2 different morphotypes in the Atlantic Ocean. Deep sea dolphins are larger and more powerful than near coastal dolphins, and dolphins living in estuaries and tidal rivers don’t even interbreed with dolphins living off the coast.  Yet, these 3 separate populations are considered the same species.  The extinct species of pygmy sperm whales may have also occupied different habitats.

The pygmy sperm whale fossils came from phosphate mines in Florida and spoil piles originating from Lee Creek Mine in North Carolina.  The Florida site is thought to yield fossils that are 5-4.7 million years old, and fossils from Lee Creek Mine are estimated to be between 4.8-3.1 million years old.  Ear bones of the larger morphotype were found at both sites, but the smaller morphotype was found exclusively in Florida.

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Pygmy sperm whales are barely bigger than bottle-nosed dolphins.

Dwarf Sperm Whale Ear

Dwarf sperm whale ear bone.  The dwarf sperm whale is not the same species as the pygmy sperm whale.

The extant pygmy sperm whale ( Kogia breviceps ) grows to 11 feet long and feeds upon squid, octopus, and shrimp.  They release a kind of ink from their intestines when they are attacked by large sharks or killer whales.  I think this defense strategy is unknown among any other species of mammal.  Pygmy sperm whales are related to dwarf sperm whales ( K. sima ), and the more famous hero of the novel, Moby Dick ( Physeter macrocephalus ).  Like their larger cousin, pygmy sperm whales locate their prey using echolocation.

The sperm whale family had more relatives during the Pliocene, but those extinct species are so little known and so little evidence of them remains that we will probably never know what made each unique.

Reference:

Velez-Jaurbey, Jorge; A Ward, and C. Pimento

“Pygmy Sperm Whale (Odostecenti, Kogiidae) from the Pliocene of Florida and North Carolina”

Journal of Vertebrate Paleontology 2016

 

Panthera atrox: the 1007 Pound Giant Lion

January 31, 2017

An extinct species of lion ( Panthera atrox ), similar but larger than the extant African lion ( P. leo ), occupied open habitat in North America from California to South Carolina and Florida for over 300,000 years.  The American lion evolved from the also extinct Eurasian cave lion ( P. spelea ) when the ice sheet that covered Canada isolated the 2 populations from each other. The 2 species never re-connected during interglacials because extensive spruce forests, an unfavorable habitat for lions, grew between them.  Fossil evidence of large carnivores is relatively uncommon because their populations are smaller than those of their prey. But there are 2 fossil sites that preserved a considerable number of carnivores due to unusual circumstances, and scientists were able to collect enough lion specimens from them to study and compare the anatomy of the species as a whole.  The 2 sites are Natural Trap Cave in Wyoming and the Rancho La Brea Tar Pits in California. Scientists estimated average body size and the results were astounding.

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Hercules is the world’s largest cat. It is a 922 pound lion x tiger hybrid that lives at the Myrtle Beach Safari Preserve in South Carolina.  It is smaller than the estimated size of the largest known fossil specimen of North American lion, an extinct species that formerly lived coast to coast.

The largest male Panthera atrox specimen came from an animal that was estimated to weigh 1007 pounds, though the average male weighed 544 pounds.  The largest female American lion was estimated to weight 577 pounds, while the average was 390 pounds.  By contrast the average extant African male lion weighs 392 pounds.  This means the average female American lion was about the size of the average male African lion.  The large difference in size between the sexes, known as sexual dimorphism, suggests American lions lived in social prides like their African cousins.  An 1000 thousand pound lion would be too large and slow to hunt successfully enough to sustain its bulk, but instead relied on the smaller more agile females to secure all the bison, horses, and camels he required.  A large pride could probably even take down a full grown mammoth.

The large size of the males helped them fend off other male lions that wished to usurp their mating rights and kill their offspring.  The enormous powerful males could also aid in protecting the pride’s kills from competing carnivores such as bears, saber-tooth cats, and dire wolves.  American lions had longer legs and bigger braincases than African lions, so they were faster runners and smarter as well.  P. atrox really was a king of the beasts.

Reference:

Wheeler, H.T; and G.T. Jefferson

Panthera atrox: Body Proportions, Size, Sexual Dimorphism, and Behavior of the Cursorial Lion of the North American Plains.”

In Papers on Geology, Vertebrate Paleontology, and Biostratigraphy in Honor of Michael O. Woodburne edited by L.B. Albright III

Museum of Northern Arizona Bulletin 65

6 Scariest Species to have Ever Lived in Georgia

October 30, 2016

6. The Hell Pigs

Vicious entelodonts lived on earth from the late Eocene to the mid Miocene (for over 20 million years).  They were 4 feet tall and reached weights of 930 pounds.

Entelodonts are known as hell pigs because their fossil remains represent a once terrifying animal that resembled a giant pig.  They occurred across most of the Northern Hemisphere, and there were many species over time.  Entelodonts existed between 37.2 million years BP-16.3 million years BP.  Although they resembled pigs, anatomical evidence suggests they were more closely related to the common ancestor of hippos and whales.  Enteledonts were 4 feet tall and weighed up to 930 pounds.  They were fast runners, and paleontologists believe they rammed into their prey, knocking their victims down and biting them until their bones were broken, probably similar to the way hippos kill humans in Africa today.  Fossil evidence of enteledonts has been found in Twiggs and Houston Counties in Georgia.  The tooth found in Houston County compares favorably with Archaeotherium, a once widespread species of enteledont.

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Entelodont tooth found in Bonaire, Georgia.  I am not the author who took a photo of this tooth. This photo was made by Thomas Thurman and it’s from his http://www.georgiasfossils.com website.

4. (tie) The Giant Short-faced Bear (Arctodus simus) and the Saber-toothed Cat (Smilodon fatalis)

I can’t decide which 1 of these was more frightening.  Giant short-faced bears were on average as large as Kodiak bears–the largest subspecies of brown bear ( Ursus arctos ).  However, they probably made a lot of noise and could be easily detected and avoided.  Saber-tooths were ambush predators and could sneak up on prey in the dark or in thickly vegetated habitat.  Arctodus was much larger, weighing about 1000 pounds compared to ~350 pounds for Smilodon.  But the latter was very powerful and sported fangs.  Fossil evidence of this big cat has been found in all of the states bordering Georgia.  Fossil evidence of Arctodus has turned up in an Alabama county adjacent to Georgia as well as several sites in Florida.  Both undoubtedly once ranged into Georgia.

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Giant short-faced bear and saber-toothed catThe illustration of this saber-tooth is inaccurate.  Smilodon had a bob-tail and their forelimbs were much more powerfully built than depicted here.

3. Appalachiosaurus

 

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Appalachiosaurus terrorized upstate Georgia during the late Cretaceous.

Appalachiosaurus was a species of tyrannosaur that lived on the eastern side of the Western Interior Seaway during the late Cretaceous (~80 million years BP-65 million years BP).  They were the top land predator, probably hunting hadrosaurs or anything else they could catch.  Fossil evidence of this species has been excavated from Hannahatchee Creek near Columbus, Georgia.  The type specimen, a nearly complete skeleton, was found in Alabama.

2. Deinosuchus rugosus

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Evidence suggests Deinosuchus rugosus ate tyrannosaurs.

This extinct crocodylian, a relative of alligator ancestors, grew to an estimated 36 feet long and weighed up to 17,000 pounds.  They were large and powerful enough to seize and drag a tyrannosaur into the water, and there is some fossil evidence they preyed upon them.  They likely ate dinosaurs as a significant part of their diet.  Fossil evidence of this species has also been found in Hannahatchee Creek as well as the Chattahoochee River in Georgia.

1. Man (Homo sapiens)

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Homo sapiens is clearly the scariest species to have ever walked on earth.  Here is a photo of an atomic bomb mushroom cloud.  Humans can wipe out entire cities with nuclear weapons.

Human beings construct weapons of mass destruction capable of turning livable habitat into uninhabitable wasteland.  I can’t think of anything scarier than that.

Stuff I Find While Looking up Other Stuff

October 14, 2016

Many of my blog topics originate from information I gathered while researching other blog topics.  My most recent essay is a good example of this process.  I recently reread Rise and Fall of the Third Reich by William Shirer, and this author mentioned another book that interested me.  The Wall  about the Jewish uprising in Warsaw during 1943 is a collection of journal excerpts edited by John Hersey.  I looked for this book on amazon.com and discovered another book by the same author, but this 1 was about bluefish.  I ordered that book too, and it inspired me to write my recent essay about bluefish.  While researching for more information about bluefish, I recalled John Lawson’s brief description of this species in his book– A New Voyage to Carolina. I have this book on my bookshelf, but it was quicker to look for this passage online.  When looking for this passage, I discovered a paper that analyzed the content of Lawson’s book.  I’ve always been fascinated with A New Voyage to Carolina  because it is the very first natural history book ever written in North America.  So I read this paper and learned the “grampus” described by Lawson is an alternative archaic name for Risso’s dolphin.  I became curious about this little known species and decided to write a blog entry about it.  This species is poorly studied and I couldn’t find much about it.  However, I did come across a study that determined Heinrich events caused annual mass whale strandings, and this led to my previous essay, an entry that is far more interesting than any I could have written using the meager scientific literature focused on Risso’s dolphin. The internet is a nearly infinite encyclopedia, and it’s easy to get distracted, but I think these distractions lead to my most interesting blog entries.

Risso’s Dolphin

Illustration of Risso’s dolphin.  Note the scars from its battles with squid–its favorite food.

Risso’s dolphin ( Grampus griseus ) diverged from an ancestor that also gave rise to false killer whales ( Pseudorca crassidens ) about 6 million years ago.  Risso’s dolphins usually live well offshore in pods of 10-50 individuals, and their diet almost exclusively consists of squid.  Adults have many scars, resulting from battles with the tentacular cephalopods, whose suckers tear away flesh.  According to Wikipedia, Risso’s dolphins hybridize with bottlenosed dolphins ( Tursiops truncatus ) in captivity.  This seems odd because they are not that closely related. Risso’s dolphin is little studied, and as I mentioned above, I couldn’t find enough about them to write a more compelling essay, but at least they led me to the paper that inspired Monday’s blog entry.

Reference:

Hair, R.

“John Lawson’s Observations on the Animals of Carolina”

The North Carolina Historical Review 2011

After the Apocalypse: My House at 20, 100, and 10,000 Year Intervals

September 23, 2016

Alan Weisman’s book, The World Without Us, in part inspired my blog.  In his book he imagines a world where humans suddenly become extinct, and he speculates about the resulting ecological changes and how anthropogenic structures would decay.  I am particularly interested in landscapes devoid of human influence.  I chose to devote my blog to the paleoecology of southeastern North America as it was before people lived here, rather than after people become extinct.  But for this blog entry, I am going to speculate about what changes would occur to my lot and my immediate neighborhood, if a plague suddenly wiped out 100% of worldwide humanity.

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Without anyone around to maintain it, my house would become covered in grape vines, Virginia creeper, and pine straw in 3 years.  After 100 years the only thing left standing would be the chimney.  Sand, held down by pioneer plants, would cover the road completely.

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During the growing season, I have to  constantly cut back the Virginia creeper that otherwise would completely cover my house.

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My peach trees would probably die in less than 20 years, but my blueberry bushes, persimmon and mulberry trees, and chives would likely still be alive after 20 years.

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My patch of sunchokes would last decades…until trees shaded them too much.

My House 20 Years After the Extinction of Homo sapiens

I rake the pine straw off my roof twice a year and cut back Virginia creeper and grape vines twice a month during the growing season.  Without me all 3 completely covered my house in 3 years.  This hastened wood rot.  A sagging area of my roof caved in and several generations of squirrels have lived in the attic.  The house is still standing, though the roof leaks in numerous places and the inside smells like mildew.  An oak tree in the front yard is now quite large and some of its branches cover my daughter’s Toyota Corolla.  The tires on both Toyotas are flat, and the metal bodies are rusting.  A hailstorm cracked windows, and some are shattered.  Mosquitoes breed in puddles on the floorboard of 1 of them.

The peach trees in my scrub-covered backyard have died, but the mulberry, a native tree, is thriving and forms a closed canopy on the side of the yard with a black cherry and oak.  Both native fruit trees provide plenty of summer food for songbirds.  Much of the backyard is near impassable thicket and home to a happy family of rabbits.  The lot across the street from mine is also a thicket of pine and oak saplings and persimmon, most of it covered in vines.  Before people became extinct, a street sweeper kept sand from covering the road in front of my house.  But now most of the road is covered in sand, leaves, pine straw, and other organic debris; and pioneering grasses and flowers are taking root in many places.  The road is the only passable track in the vicinity and serves as an animal trail.  Scat of all kinds is visible.

Human hunters and automobiles caused a 30% annual mortality rate in the deer population.  But after humans became extinct the deer population skyrocketed, and it is still high 20 years later.  Herds of 200 occasionally form, and they browse down much  of the vegetation but here in the south with a long growing season, they never starve.  Instead, predator populations increased and partially keep the deer population in check.  Both coyotes and bobcats take a toll, especially on spring fawns.  Wild hogs have expanded out of nearby Phinizy Swamp and are regular travelers along the road.  They eat pine sapling roots and acorns but don’t seem to be having a big impact on the dense young forests popping up everywhere.  Rabbits like the yards that have become covered in scrub habitat.  Feral cats hunt them.  They are still abundant but suffer shorter lifespans without people feeding them.  Packs of feral dogs are uncommon because coyotes outcompete them.  Cougars and bears are increasing elsewhere but have not yet colonized the vicinity.

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Without humans cats would be just as abundant as they are now, but they would have shorter lifespans.

My Lot 100 Years After the Extinction of Homo sapiens

The chimney is the only structure still standing from my old house.  Most of the houses on this street look like collapsed ruins.  Some power line poles have rotted and tipped over, and during several ice storms trees smashed through power lines.  About half the poles still stand but the wire is all on the ground covered in dense vegetation.  The ground around my former home is littered with bricks, most covered with dirt, grass, leaves, and pine straw.  A sapling is growing through a crack in the cement slab that my house formerly rested upon.  The rusty washing machine and dryer are covered in brambles.  There is a squirrel’s nest on top of the refrigerator.  A rotting pine log and all sorts of organic crud camouflage what used to be a queen-sized bed. The fabric rotted away, but the springs and metal parts can still be seen. An oak is growing through 1 of the rusted hulks that used to be a car.  My backyard is a thick forest.  However, the lot across the street is more of an open woodland.  Perhaps a fire burned through that side of the road.  The road is not recognizable–scrub vegetation broke through cracks in the pavement which is now only visible in a few eroded places.  However, an animal trail still winds around in the general direction of where the road used to be.

Deer and wild hog are still abundant and are preyed upon by coyotes and bobcats here, but a cougar includes my lot as part of his territory.  Bears occasionally pass through too, looking for turkey eggs, for there is a big flock roosting in the vast local woods.

My Lot 10,000 Years After the Extinction of Homo sapiens

There is no trace of my house, at least on the surface.  Bricks, metal, and plastic are buried under several feet of sediment.  The surrounding landscape is an open woodland consisting of loblolly pine and sand laurel oak–the species that have long co-dominated this belt of fall line sand hills.  The trunks on many of the oaks are 6 feet thick, but the poor soil keeps them from growing very tall.  Fire and megafauna foraging maintain a grassy understory between the widely spaced trees.  The climate is beginning to gradually sink into an Ice Age, but the change is imperceptible to the great herds of horses, long-horned cattle, bison, wild boar, and deer that live in the vicinity.  Jaguars long ago joined the cougars and wolves in hunting the hooved animals.  The wolves descend from coyote x dog hybrids.  They evolved to a larger size that helps them bring down larger prey.  Bears are abundant, but feral cats, along with other small predators such as raccoon, fox, and opossum are less common than they were in anthropogenic environments because the larger predators keep their populations in check.  It’s almost like the Pleistocene again.

 

Possible New Megafauna Kill Site Found in Mexico

September 18, 2016

Whenever news organization report new paleontological discoveries, I can always count on the journalist to sensationalize the find, and they often make assumptions that are factually incorrect.  Here is an example.  A mostly complete Columbian mammoth (Mammuthus colombi) was unearthed in Tultepec, Mexico in December 2015 when workers digging a trench for a new sewer line found the bones 6 feet below the surface of the ground.  Luis Cordoba Barradas, a Mexican archaeologist, took over the excavation.

Image result for tultepec mexico map

Location of Tultepec, Mexico where the remains of 1 mammoth were found 6 feet underground.  It may have been butchered by humans.

Mexican archaeologist Luis Cordoba works on parts of a skeleton of a mammoth discovered in December 2015 in Tultepec, Mexico 

Mammoth skull with intact tusks in the process of being excavated in Tultepec.

Over a dozen news services reported the discovery, but important information is missing from all the reports.  This particular mammoth lived some time between 14,000 BP-12,000 BP and was 20-25 years old at the time of its death.  According to all the reports, the position of the bones suggests possible human butchery.  But this is a sensationalist overreach because many of these reports left out the alternative explanation–the position of the bones could be attributed to human butchers OR natural predators scattering the bones.  None of the new reports go into the details of why this might be considered a human-killed specimen.  Were stone tools found associated with the bones?  Are butcher marks on the bones?  Did they find animal gnaw marks?

A detailed description of the specimen hasn’t been published in the scientific literature yet, as far as I know.  The area was a lake during the late Pleistocene, and the mammoth may have been stuck in the mud when it was killed.  I would be interested in the stratigraphic context, but I’ll probably have to wait until the important details are published in a journal.  (I did send the archaeologist an email, asking him for more details.  I’ll post his response, if he sends me one.)

The news reports reveal the confusion of the original reporter.  More than 1 report mentions that this specimen was a subspecies of mammoth.  Obviously, many of the articles were simply copied verbatim from information reported in someone’s original report. (In other words…plagiarized)  I think this journalist was under the mistaken impression that the Columbian mammoth was a subspecies of the woolly mammoth (Mammuthus primigenius).  This is incorrect.  The Columbian mammoth was a distinct species, though recent genetic evidence, along with old anatomical studies, show the 2 species interbred where their ranges overlapped.  (See: https://markgelbart.wordpress.com/2016/02/18/the-southern-and-northern-range-limits-of-the-columbian-mammoth-mammuthus-colombi/ )

Hopefully, a scientific journal will publish a paper about this species because the news reports are just so inadequate.