Posts Tagged ‘Canis dirus’

The Enigmatic Small Wolf Species of the Early-Mid Pleistocene of North America

August 6, 2017

There were at least 5 species of wolf-sized canids living in North America from about ~1.8 million years BP-~300,000 years BP.  Edward’s wolf (Canis edwardii) was a medium-sized canid, averaging about 75 pounds, that apparently occurred from coast to coast.  It’s the same species formerly known as Canis priscolatrans, and it was an evolutionary dead end–its extinction occurred about 300,000 years ago.  Armbruster’s wolf (Canis armbrusteri) co-occurred with Edward’s wolf but was a larger species, weighing on average 125 pounds.  Armbruster’s wolf is thought to be the evolutionary ancestor of the famous dire wolf (Canis dirus) which became extinct about 11,000 years ago.  Troxell’s dog (Protocyon texanus) was related to African hunting dogs.  Fossil evidence of this species has been found in Texas, the Yukon, and Alaska; and it probably had a wider range than the fossil record indicates.  Perhaps it lived in low numbers in geographic regions where processes of preservation were rare. The timber wolf (Canis lupus) was apparently confined to Alaska and Eurasia during the mid-Pleistocene and didn’t colonize North America until the late Pleistocene.  Finally, a mystery species nearly identical to the present day coyote (Canis latrans) left fossil evidence at sites in Nebraska, Colorado, California, Arkansas, Pennsylvania, Maryland, and West Virginia.  Some of the fossils at these sites are estimated to be 1 million years old.  Paleontologists identified these specimens as Canis latrans, though they cautiously also referred to them as coyote-like.  However, a recent study of wolf, coyote, and dog genetics determined the coyote is a recently evolved species no older than 50,000 years when it first diverged from timber wolves.  This result suggests the mid-Pleistocene species identified as Canis latrans may be an extinct mystery species.

In addition to the fossil record scientists can use a molecular clock to determine when 2 or more species diverged from a common ancestor.  A species has a fixed mutation rate, and scientists add up generations of mutational changes to determine the time of divergence from its closest related species.  (This is a vastly oversimplified explanation but will suffice for the purpose of this blog article.)  There are problems with using molecular clocks.  Different species have different rates of mutation, and the mutation rate can change over time.  Scientists try to calibrate the molecular clock with the fossil record by using various statistical methods.  An early study of wolf and coyote genetics determined the 2 species diverged about 1 million years ago, and this result is consistent with the fossil record, but the results of the newer study mentioned above totally contradict the fossil evidence.  There are 2 explanations for this discrepancy.  a) The new study is wrong.  Maybe the scientists used too many assumptions and dodgy statistics and just came up with the wrong number.  or b) The new study is right, and the mid-Pleistocene species identified as Canis latrans was an evolutionary dead end that went extinct.  The similarity between this mystery species and Canis latrans is just a remarkable example of convergent evolution. c) The new study is right and is not inconsistent with the fossil record.  Perhaps the common ancestor of the coyote and timber wolf was coyote-like.  Ice Age glaciers caused the divergence.  Populations north of the Cordilleran ice sheet evolved into timber wolves but populations south of it remained coyote-like.

Below are images of mid-Pleistocene  skull and jaw specimens identified as Canis latrans along with the skull and jaw of a present day coyote.  I can’t tell the difference, so I favor explanation a.  Even in a case of convergent evolution, there would have to be some notable anatomical differences between 2 different species.

Image result for irvingtonian Canis latrans skull

Genetic evidence from 1 study suggests coyotes diverged from gray wolves about 50,000 years ago.  However, this skull, assigned to Canis latrans (coyote) from Maryland dates to >300,000 years ago.  Is the genetic evidence incorrect or was there a species then so similar to modern coyotes it deceived paleontologists? Image from the below referenced paper by Tedford et. al.

Image result for Canis latrans skull

Present day skulls of Canis latrans.

Some zoologists think coyotes and dogs should now be classified as subspecies of timber wolf based on the data from the newer genetics study.  I don’t agree.  The behavioral characteristics of wolves, dogs, and coyotes are too dissimilar; and they don’t normally interbreed in natural conditions.  Humans can easily eradicate wolves from a region, but they can not eliminate coyotes because the latter are so much better adapted for living close to people.  Wolves and coyotes can survive in the wilderness, but they make terrible pets.  Most dogs make excellent companions for people but can’t survive in the wild.  In my opinion wolves, coyotes, and dogs are closely related but definitely different species.

References:

Tedford, Richard; X. Wang, and B. Taylor

“Phylogenetic Systematics of the North American Fossil Caninae”

Bulletin of the American Museum of Natural History  2009

Von Holdt, Bridgett; et. al.

“Whole Genome Sequence Analysis Shows that Two Endemic Species of North American Wolf are Admixtures of Coyote and Gray Wolf”

Science Advances (27) July 2016

Wilson, Paul; et. al.

“DNA Profile of Eastern Canadian Wolf and Red Wolf Provide Evidence for a Common Evolutionary History Independent of the Gray Wolf”

Canadian Journal of Zoology 2000

 

 

 

Advertisements

Pleistocene Fossil Canid Ratios Recorded in the University of Florida Database

January 11, 2012

The abundance of Pleistocene fossil sites in Florida has allowed the university in Gainesville to become a center of information for other scientists.  Scientists excavating new fossil sites use existing fossils at the University of Florida Museum of Natural History to help identify the new specimens they pull from the earth.  It’s not always easy to differentiate closely related species–the subject of this blog entry, the canids, are notoriously difficult to distinguish.  Vertebrate zoologists and paleontologists measure and describe every part of every bone and tooth when examining new specimens.  They publish this information in scientific journals and accumulate knowledge of the size limits and shape variations of a particular species’ anatomy.  If a newly discovered fossil tooth for example doesn’t fit any known pattern of shape or size, than scientists suspect they may have discovered a new species.  The more data scientists have, the better able they are to identify new species and spot evolutionary trends over time within a species.

Fossil collecting is popular in Florida, thanks to all the sinkhole lakes and caves with basal chemistry in the soil that preserves bones.  Amateur fossil collectors have many more fossils in their collections than the University of Florida’s Natural History Museum..  Many are for sale as well.  It would be a great benefit to science, if collectors made arrangements to donate their collections to the museum upon their deaths.  Many valuable specimens have been lost when their owners die and family members, not interested in the subject, lose track of where they put the old bones.

My little study is limited to canid fossils listed on the University of Florida database and leaves out the great many more in the hands of amateur fossil collectors.  I also limited this survey to the Rancholabrean Land Mammal Age (300,000 BP-11,000 BP), leaving out Armbruster’s wolf which dominated the middle Pleistocene before being replaced by dire wolves.  Nevertheless, I think there’s enough information to suggest relative canid species abundance during the late Pleistocene.  Keep in mind, I was counting on a computer screen while scrolling down, so my numbers may be off slightly.

Listed on the Florida Museum of Natural History’s database, I counted 64 dire wolf (Canis dirus) specimens, 34 coyote (Canis latrans) specimens, 1 red wolf (Canis niger) specimen, 9 domestic dog (Canis familiaris) specimens, 0 dhole (Cuon alpinus) specimens, and 55 gray fox (Urocyon cineorgenteus) specimens.

The fossil record strongly suggests that from 300,000 BP to about 11,000 BP dire wolves were by far the most common large canid being about twice as abundant as coyotes.  Red wolves were rare but present.  Gray foxes were just as common during the Pleistocene as they are today.  These neat little foxes have the ability to climb trees, a skill that saves them from their larger relatives.  There is no evidence of dholes but as I wrote in a previous blog entry http://markgelbart.wordpress.com/2011/06/01/did-the-dhole-cuon-alpinus-range-into-southeastern-north-america-during-the-pleistocene/ , I suspect they may have periodically colonized parts of the southeast but in numbers too low to leave fossil evidence.

Dire wolves were the dominant large canid in the southeast (and all across North America south of the Ice Sheets) during the late Pleistocene.

Coyotes probably occupied a niche similar to African jackals.

Gray foxes thrived in areas where they had access to trees and could escape larger predators.

The presence of domesticated dogs in the Pleistocene fossil record puzzled and surprised me.  I almost didn’t even do a database search for Canis familiaris and only did so as an afterthought.  Most anthropologists don’t think humans domesticated dogs until after the Pleistocene about 10,000 years ago, but the fossil evidence contradicts this.  In fact scientists recently discovered the skull of a domesticated dog in a Siberian cave that dates to 33,000 BP.  They determined  this particular domesticated dog was not the ancestor of the lineage that led to today’s dogs but instead its descendents died out.  It’s probable that there were many early lineages of domesticated dogs that ceased to exist for various reasons.  Perhaps that group of people died out or stopped keeping dogs.  The popular idea that people domesticated dogs by kidnapping and raising wolf pups is a misconception.  Scientists think it’s the other way around–dogs adopted us.  Dogs are descended from the wolves which had the least flight response.  Wolves that hung closely around human campsites for access to leftovers gave birth to pups with floppy ears, multi-colored coats, and other dog traits that differentiate them from other wolves.  The gene for tameness shares a pathway with the gene for these physical characteristics.  So it’s likely that dogs adopted people in many different geographic locations wherever wolves (Canis lupus) began occupying areas adjacent to human campsites.  Obviously, dogs either followed or were brought to Florida by the Paleo-Indians.

The authors of a chapter in the book The First Floridians and the Last Mastodons suggest that all the coyote fossils found in Florida are actually domesticated dog fossils, but they only knew of a handful of coyote fossils.  Apparently, they didn’t know 34 specimens had been found.  I doubt scientists made that many misidentifications.

Dire wolves succeeded in becoming one of the dominant predators in the environments of southeastern North America where they found a wealth of prey roaming the open woodlands and savannahs.  Everything from bison and horses to deer and rabbits sustained them, and a mammoth or mastodon that died of natural causes provided a feast.  Coyotes successfully co-existed with dire wolves by scavenging large predator kills and by hunting rodents.  Red wolves must have been restricted to islands and perhaps deeply wooded swamps where they could survive on deer and small game.  Their niche must have been areas with lower densities of prey as opposed to grasslands that hosted large herds of ungulates.  Following the extinction of the megafauna and dire wolves, forests replaced grasslands and red wolves increased in number and drove coyotes completely out of the south.  But after European settlers wiped out the red wolves, coyotes returned.

References:

Ovodov, Nikolai, et. al.

“A 33,000 Year Old Incipient Dog from the Altai Mountains of Siberia: Evidence of the Earliest Domestication Disrupted by the Last Glacial Maximum”

Plos One 6 (7) 2011

http://www.flmnh.ufl.edu/databases/vp/intro.htm

The Dunwoody Nature Center

I attended my nephew’s bar mitzvah in Dunwoody, Georgia last weekend.  Dunwoody consists of dozens of subdivisions and plenty of shopping centers and absolutely no rural farmland.  I didn’t hold out much hope for a nice nature walk here–the traffic is terrible.  But at least the developers left a lot of trees standing.  I decided to walk from my sister’s house to a little park known as the Dunwoody Nature Center and I discovered a surprising gem.

This white oak was about 4 feet in diameter.  White oak is a common tree in Dunwoody.

From the composition of the trees left standing most of Dunwoody must have once hosted a pretty nice dry upland forest.  Too bad developers converted it into a crowded suburb.  Today, white oaks, black oaks, southern red oaks, shortleaf pines, and loblolly pines are the dominant trees.  The Dunwoody Nature Center slopes sharply down toward Wildcat Creek, the name of which is a relic to its former status as a wilderness.  The woods here are dominated by beech, white oak, sweetgum, river birch, and loblolly pine.  I was stunned to see a woodlot of mostly beech trees in central Georgia.

A mature beech tree growing on the edge of a rocky creek.  It’s surrounded by many immature beech saplings.

Fossil pollen studies show beech was a common tree in the south during the end of the Ice Age when the Laurentide glacier began melting and releasing more moisture in the atmosphere creating a climate that was still cool but more rainy than it was during the height of the Ice Age.  The presence of abundant beech in the fossil record is indirect evidence of massive flocks of passenger pigeons.  Passenger pigeons fed on acorns–in some places completely eliminating the oak seed crop…and the beech’s competition.  Although beech trees produce an edible nut, they can also spread from roots and could survive their seed being consumed by passenger pigeon flocks.  Since the passenger pigeon’s demise, oak forests have been replacing beech forests in many areas.  So I was delighted to see this remnant beech forest in central Georgia.

Wildcat Creek flows through a granite outcropping.  Here is a miniature waterfall.

Two little league baseball fields take up about half the space of the park.  The park is heavily used by dog and toddler walkers.  It’s popularity shows that the planning commission in charge of developing Dunwoody should have arranged for the purchase of more land for more parks.

Irrational Anti-Wolf Hysteria in the Rocky Mountains

July 21, 2011

Photo of Yellowstone gray wolves from google images.  Note the color variations within the same pack.

The timber wolf (Canis lupus) is a beautiful animal well adapted to hunting big game.  It’s an ancient species having first evolved in Eurasia about 1 million years ago.  They crossed the Bering Landbridge and became widespread in western North America at least 300,000 years ago.  Based on the number and distribution of fossil specimens, dire wolves (Canis dirus) outnumbered timber wolves during most of the Pleistocene in the southern regions and lowlands, and apparently, timber wolves never penetrated the southeast, perhaps because red wolves (Canis rufus) were already present and occupying a niche not directly in competition with dire wolves.

The extermination of wolves from Yellowstone National Park and many sparsely populated regions of the west was an ecological disaster.  Elk and deer overpopulated the range, forcing National Park officials into the awkward position of having to shoot elk inside National Parks.  Canadian wolf populations rebounded, and they began recolonizing Montana and Idaho naturally in the early 1990’s.  Scientists reintroduced wolves back into Yellowstone National Park in 1995, improving the quality of the ecosystem.  Wolves now number between 1300-1600 in the northern Rocky Mountains.  Idaho held a spring hunting season on wolves in 2010 that led to the deaths of 188, not counting the puppies that starved to death following the deaths of their parents. 

The furious anger of irrational wolf haters pressured the Idaho Fish and Game Department into planning annual hunting seasons on wolves that will begin this upcoming fall, unless a lawsuit stops it.  The Idaho Fish and Game Department itself showed a bias in favor of killing wolves with the leading questions they asked on a pre-hunt survey such as “”Should wolves be managed to protect public safety?” instead of questions I would ask such as “Should wolves be slaughtered so their puppies will starve?”

The hatred of wolves is not based on reality or facts and seems most vocal among hunters who believe humans are the only animals on earth with the God-given right to kill other animals.  Although the Idaho Fish and Game Department only wants a sustainable “harvest” of wolves, many militant anti-wolf fanatics insist that wolves should be completely exterminated.  According to them, wolves “destroy all wildlife” and are causing big game populations to collapse.  It doesn’t occur to them that wolves are wildlife.  Hunter “harvest” statistics don’t support their erroneous beliefs.  I researched this and discovered how wrong they are.

Hunter “Harvest” Record from Wyoming Fish and Game Department for Selected Years

…………………………………..Elk …………………………..Deer

1994…………………………….24,534…………………………………….44,488

1996……………………………..20,612…………………………………….NA

2001…………………………….22,772…………………………………….47,943

2009……………………………22,971……………………………………..53,267

Note the elk “harvest” has remained steady in Wyoming, despite the reintroduction of wolves.  Deer “harvests” show a noticeable rise.  People spent an estimated $35 million in Wyoming just to see wolves, so their reintroduction has been beneficial economically as well as ecologically.

Hunter “harvest” table from Montana Fish, Wildlife, and Parks from selected years

……………………………………….Elk………………………..Deer

2001……………………………….20,578………………….111,783

2004……………………………….23,313…………………..119,266

2005………………………………26,201…………………….115,238

2010……………………………….24,744……………………94,730

Again, elk populations show no signs of collapsing.  Deer show a slight decline in the most recent year but this may be due to a severe winter.

According to the Idaho Fish and Game Department, in 2010 the elk population there was above management goals in 10 districts, within management goals in 13, and below management goals in 6.  Since wolves recolonized the state, the elk population has declined from 125,000 to 100,000, but “deterioration of habitat” is considered a greater factor than wolves, especially in districts where wolves are getting blamed.  There has been no economic loss due to a decline in big game tags issued.

Clearly, there is no collapse in big game populations in areas wolves have recolonized.  In any case I’ve asked some of these wolf haters how wolves could be increasing in numbers, if the population of their prey was supposedly collapsing.  A dearth of game would cause wolves to starve and decrease in numbers.  I’ve yet to see an answer to this logical point  that makes any sense.  One man insisted that after wolves exterminate elk they’d gobble up everything else including people–an ecological impossibility.

Many ranchers hate wolves as well.  However, losses of livestock to wolves is minimal.  In 2007 in Idaho ranchers lost 53 cattle, 170 sheep, and 8 dogs to wolves.  This out of a population of 2.2 million cows, 235,000 sheep, and probably hundreds of thousands of dogs.  For cattle this can be calculated to a loss of something like .000002%.  Infinitesimal.

Wolf haters also have an irrational fear that wolves will attack people.  The chances of this happening are remote–in North America there have been about 25 reported attacks of wolves on humans in recorded history.  In Europe and Asia documented wolf attacks on people number in the thousands.  In the Old World only the nobility were allowed to hunt and wolves didn’t learn to fear peasants; but in America where more people have guns in an egalitarian society, intelligent wolves did learn to avoid people.  Contrast these 25 reported wolf attacks in all of American history with 34 people killed by domesticated dogs (Canis familiaris) in the U.S. in one year, and the estimated 4.7 million dog attacks annually.  Yet, no rational person is calling for the extermination of domesticated dogs.

I’m not opposed to hunting for food. In my irregular series on this blog about my imaginary life living in Georgia 36,000 years BP, I hunt deer, elk, peccary, and bison for most of my meat (see the March archives for my most recent post on this).  But I’m disgusted with the attitude of many hunters today, and this certainly includes wolf haters who are all hunters unable to stand seeing other animals kill their game.  Direct TV offers 2 hunting channels.  More often than not on the hunting shows I’ve watched, hunters giggle like demented sadists after they’ve killed an animal.  When it comes to politics, the overwhelming majority of hunters are twisted fascists.

July 26, 2011 anti-wolf rally Federal judge Donald Molloy could once again halt a much needed wolf control hunt. - Sportsmen Needed To Protest Latest Wolf Hearing In Montana!

The controversial judge ruled against wolf haters in 1 case.  Freedom of speech does not include terroristic threats.  Whoever fashioned this sign should be arrested. (Note: the link to this photograph originally featured a picture of anti-wolf nuts hoisting a sign threatening Judge Molloy who ruled that wolves should remain protected.  Instead the photo on the embedded link was replaced with this asshole carting 4 dead wolves.) 

The above sign illustrates the intolerant hostility wolf haters have for people who oppose their point of view.  This sign is all one needs to know about these people.  They’re not nice guys.

Incidentally, one of these wolf haters who runs a ridiculous anti-wolf propaganda site known as save the elk.com was arrested recently for…felony poaching of an elk.  How ironic.

Another irrational fear wolf haters share is their belief that the federal government is going to take their guns away from them.  The way they carry on, one would think they were afraid the federal government was going to take their penises away.

References:

Idaho Fish and Game News 22 (2) August  2010

Montana Fish, Wildlife, and Parks Hunters “Harvest” Tables

Wyoming Fish and Game Department Hunters “Harvest” Tables