Archive for May, 2018

An Anatomical Comparison Between the Extinct North American Cheetahs (Miracynonyx sp.) and the Late Pleistocene/Holocene Cougar (Puma concolor)

May 28, 2018

One of my readers recently asked whether the cougar (Puma concolor) might be the same species as the extinct North American cheetahs (Miracynonyx inexpectatus and M. trumani).  This is not as ridiculous a question as a layman might think because paleontologists often mistakenly identify multiple species from fossil remains that after re-evaluation are eventually determined to be from 1 species.  I love reading articles about vertebrate paleontology, but I usually skip over anatomical descriptions because they are pretty dry.  But to answer his question, I used google to search for a paper comparing the anatomical differences between Puma and Miracynonyx.  I did not find a journal article with a comprehensive anatomical comparison between the 2, but I did recall a paper I’d already read that discussed some of the differences.  I’ve linked the paper below in  my references.

Cougars and North American cheetahs had different-sized teeth.  Cougars have larger canines and lower molars than North American cheetahs, but they have smaller lower premolars (p4) and smaller upper pre-molars (P3).  They also have a “less reduced protocone on upper premolar P4.”  North American cheetahs had longer limbs than cougars as the below photos from the linked paper show.  So the answer is no.  Cougars were definitely not the same species as the North American cheetahs.

Fossil history of the panther (Puma concolor) and the cheetah-like cat (Miracinonyx inexpectatus) in Florida - Page 208

Comparison of limb bones between cougar and North American cheetah shows the latter had longer hind foot bones and were better runners.

Fossil history of the panther (Puma concolor) and the cheetah-like cat (Miracinonyx inexpectatus) in Florida - Page 210

North American cheetahs had longer front foot bones as well.

Cougars and North Americans cheetahs are closely related, however.  Genetic evidence suggests their shared lineage originated 6-8 million years ago, and a puma-like cat, probably Puma pardoides, crossed the Bering Land Bridge from Asia shortly after this.  In North America the puma-like ancestor diverged into 3 lines: cougars, North American cheetahs, and jaguarundis. The Puma genus diverged from Miracynonyx about 3.2 million years ago.

The fossil evidence shows M. inexpectatus  lived all across North America from the late Pliocene to the middle Pleistocene (~3 million years BP-~300,000 years BP).  In the Florida Museum of Natural History there are 47 records in state of M. inexpectatus at sites thought to date from the Pliocene to the mid-Pleistocene, but they are known from just 1 late Pleistocene site in Florida.  This site is named Lecanto 2A. The only other Late Pleistocene site with a possible M. inexpecatus  fossil (1 leg bone) is in Cavetown, Maryland.  These specimens can’t be radio-carbon dated.  The reason the specimen from Lecanto 2A is considered Late Pleistocene is its association with specimens of other species known from this age including dire wolf, Florida spectacled bear, rice rat, and cotton rat.  It’s possible there were relic populations of M. inexpectatus  still living during the Late Pleistocene, but it seems more likely it’s a case of older fossils getting mixed with younger fossils.

M. inexpectatus  expanded its range at a time coinciding with the expansion of grassland habitat.  Its long legs helped it run down prey.  M. trumani was even more adapted for living in open habitat.  This species appeared during the Late Pleistocene and was restricted to western North America as far as we know from the fossil record.  M. trumani is probably a descendent of M. inexpecatus which had intermediate characteristics between cougars and M. trumani. 

The paleobiology database indicates cougar fossils dating to the Early and Mid Pleistocene in California, Idaho, Washington, and Mexico have been reported.  Nevertheless, cougar fossils predating the Late Pleistocene are rare.  In the Florida Museum of Natural History there are 44 records of cougar from the Late Pleistocene but just 2 from the Mid Pleistocene and 2 from the Early Pleistocene.  The early Pleistocene specimens are referred to as Puma lacrustis, but I searched for this scientific name on google and found nothing, so I’m not sure what these specimens actually were.  Genetic evidence suggests cougars were well established in South America between 300,000 years BP-200,000 years BP, and this corresponds with the widespread fossil evidence of this species throughout North America during this time period.  I hypothesize cougars began to expand their range widely during an early Rancholabrean interglacial from a regional ancestral population undetected in the fossil record.  This time period would correspond to when forested conditions expanded.  Cougars are ambush predators that prefer forests and woodlands.

North American cheetahs are not as closely related to Old World cheetahs as previously thought.  Physical similarities between the 2 are just another example of convergent evolution.

References:

Barnett, Ross; et. al.

“Evolution of the Extinct Sabretooth and the American Cheetah-like Cat”

Current Biology 15 (5) August 2005

Culver, M.; W. Johnson, J. Pecon-Slattery, and S. O’Brien

“Genomic Ancestry of the American Puma (Puma concolor)

Journal of Heredity 91 (3) 2009

Morgan, Gary and Kevin Seymour

“Fossil History of the Panther (Puma concolor)  and the Cheetah-like Cat (Miracynonxy inexpectatus) in Florida”

Bulletin of the Florida Museum of Natural History 1997

http://ufdc.ufl.edu/UF00095787/00001/1j

 

 

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Florida Cracker Cattle (Bos taurus)

May 23, 2018

Even if there were no historical accounts, modern scientists could determine when European livestock were introduced to the Americas.  Scientists can take cores of sediment, radio-carbon date it, and measure the amount of sporomiella in each dated layer.  Sporomiella is a dung fungus spore found in the excrement of large mammals and is used as a proxy to estimate megafauna populations.  Scientists know when Pleistocene megafauna populations collapsed in some regions based on the amount of sporomiella in sediment, and they also can determine when European livestock were introduced using the same method.  Following the introduction of cows, horses, and pigs; the amount of sporormiella in the environment spiked to levels often equivalent to those of the pre-late Pleistocene extinctions.

Introduced livestock frequently outlasted the initial expeditions that brought them.  Early Spanish explorers of the 16th and 17th centuries perished with regularity in the harsh New World environments, so far from their accustomed European civilization, and some were massacred by Indians, but the cattle, pigs, and horses they brought with them ran wild.  The Europeans and their livestock carried contagious infections that decimated Indian populations with primitive immune systems as well, and feral livestock thrived in environments with low numbers of people.  The husbandry practices of early European settlers facilitated the increase of feral livestock populations.  Busy missionaries and homesteaders let their animals forage in the woods and fields, and the beasts often escaped and joined their free cousins.  Local environmental conditions shaped the evolution of feral livestock, weeding out those not adapted to living wild under each region’s unique conditions.  New breeds were born.

The Florida cracker cattle, also known as the piney woods cattle, rapidly evolved to thrive in the open pine savannahs of Florida and south Georgia.  They are related to the better known Texas longhorn cattle and also descend from cattle brought by the earliest of Spanish explorers.  They were already adapted to the warm climate of Spain, but in Florida the breed evolved tolerance for the humidity and local parasites. The tough cattle readily produced many calves on the low quality grasslands of the region, and their ferocity helped them fend off cougars, wolves, and bears.   Florida cracker cattle may be the “buffalo” that William Oglethorpe, the man who founded the state of Georgia, hunted during the early 18th century.  Colonial Europeans used the term “buffalo” interchangeably for both bison and feral cattle.  William Bartram saw great mixed herds of Florida cracker cattle, horses, and deer when he traveled through Florida in 1776.

Image result for Florida cracker cattle

Florida cracker cattle.  They are small–bulls weigh between 800 pounds to 1200 pounds.  Most are brown or partly brown and white but they come in a variety of coat colors.  The name cracker comes from the British settlers, known as crackers, because they cracked whips when they drove livestock on the road.

Florida cracker cattle were the best breed of cattle able to survive in the deep south until Brahman bulls from India were introduced during the 1930s.  Then, scientists invented antibiotics and medicines to treat parasites, and farmers were able to raise more productive breeds of cattle which they crossbred with the native cattle.  The Florida state legislature passed a law in 1949 outlawing free ranging cattle because farmers wanted to prevent the transmission of diseases from wild cattle to their preferred domestic breeds.  The Florida cracker cattle population plummeted.  Now, there is an effort to save the breed.  38 people still raise Florida cracker cattle, and herds are maintained at the Tallahassee Agricultural Complex, Withlacoochee State Park, Lake Kissimmee State Park, Payne’s Prairie National Wildlife Refuge, and Dudley Farm.  Customers who like free-roaming grass fed beef pay top dollar for meat butchered from the breed.

Manatee State Park and Bradenton, Florida

May 20, 2018

I visited southwestern Florida last week to see my Mom for Mother’s Day.  We spent some time at Manatee State Park as well, and I saw lots of wildlife on my trip through the state.  There are no manatees in Manatee State Park.  Manatee Lake is a manmade reservoir, created when the Manatee River was dammed.  Manatees live in the river but they can’t get past the dam.  Manatee State Park is about 500 acres and hosts a mostly scrub environment of saw palmettos, grape vines, stunted live oaks, and Florida sand pine.  Supposedly, fox squirrels occur in the park, but I just saw gray squirrels.

I saw interesting wildlife on my trip while driving from Augusta, Georgia to Bradenton, Florida; but unfortunately I couldn’t take photos while traveling 70 mph down the highway.  I was lucky enough to spot an extremely rare whooping crane standing by I-75 south of the Tampa exit.  There are only about 100 whooping cranes in Florida.  I expected to see sandhill cranes (which I also saw), but was shocked to see a whooping crane. I saw swallowtail kites 5 times but couldn’t take photos of the birds because they wouldn’t stop moving.  My sister lives on a golf course that recently was a cattle ranch, and the wildlife hasn’t left yet, despite the development.  I did get a decent photo of a bobcat, though it was walking fast.

The list of species I saw in Florida included whooping crane, sandhill crane, swallowtail kite, Mississippi kite, osprey, king rail (I think), cattle egret, great egret, green heron, great blue heron, Canadian goose, turkey, turkey vulture, black vulture, white ibis, mourning dove, mockingbird, rufous sided towhee, blue jay, laughing gull, brown pelican, cormorant, crow, red-winged blackbird, boat-tailed grackle, chimney swift, cardinal, black bellied whistling duck (I think), house sparrows, gray squirrels, and bobcat.  I saw road-killed opossum, armadillo, raccoon, and white tail deer.  I heard barred owl, chuck will’s widow, and tufted titmouse.  In south Georgia species I saw that I didn’t also see in Florida were loggerhead shrike, red-shouldered hawk, feral chicken, and starling.

I remember riding through central Florida in the late 1970s when citrus orchards could be found on both sides of the highway for long stretches.  I didn’t see a single orchard.  Instead, the orchards have been replaced by beautiful cattle ranches with pasture surrounding groves of live oaks.  Big flocks of cattle egrets follow the grazing cows.  It is excellent habitat for black bears and cougars.  Black bears do occur in central Florida, and cougars may eventually establish a permanent population there, but currently breeding females are mostly restricted west of Lake Okeechobee.

Click on the photos below to enlarge them.

Despite the sign, my daughter and I swam in Lake Manatee.  A couple of British tourists were astonished that we dared swim in the lake..  Actually, riding in a car is much more dangerous than swimming with alligators.

Lake Manatee supplies drinking water for 2 counties.

Stunted live oaks at Manatee State Park.  Gray squirrels foraged for acorns here but I didn’t see fox squirrels.

Saw palmetto dominates Manatee State Park.

Love bugs (Plecia nearctia) were mating and were everywhere.  Dead love bugs covered my front fender.

I saw this cormorant drying its wings from my sister’s back porch.  (At least I think it is a cormorant and not an anhinga.  It’s difficult to tell from the back.)

I took a blurry photo of a bobcat on the golf course behind my sister’s house.  It was walking fast and wouldn’t let me take a clearer photo.  It was headed toward an area inhabited by wild pigs.  We heard a squeal shortly after I took this photo.  Maybe the cat grabbed a piglet.

I think this is a black bellied whistling duck.  Initially, there were 3 of them on my sister’s roof.  The fulvous whistling duck also lives in Florida.  Both of these Central and South American species are expanding their range north.  All the houses in my sister’s neighborhood were built with these hurricane-proof roofs.

 

The Chesser Island Boardwalk in the Okefenokee National Wildlife Refuge

May 16, 2018

Miles of open pine savannahs formerly surrounded the Okefenokee Swamp, but that land has been almost entirely converted into enormous pine tree farms with much less floral and faunal diversity.  100 years ago, developers tried to ruin the swamp itself as well.  They felled cypress forests and attempted to drain the swamp with canals.  Thankfully, they were bankrupted because the swamp was too resilient and impossible to develop, so the government designated it a wildlife refuge.  There is a nice boardwalk at the end of Chesser Island Road that leads to an observation tower.  I walked to the tower last Saturday with my wife and daughter and took the following photos.

The entrance road leads through a slash pine savannah with an undergrowth of saw palmetto, ferns, and wiregrass.

2 big alligators were hanging around a lily-covered roadside ditch.

Ferns are abundant in fire-adapted landscapes, like the Okefenokee.  Ferns were the first plants to sprout following the K-T impact that wiped out the dinosaurs.

Fire creates the open landscape of the Okefenokee.  Without fire it would become a closed canopy cypress forest.

Barred owl.  They are common in the swamp.

The fire of 2013 killed lots of cypress trees.  Note the charred trunks.

The boardwalk is 3/4 of a mile.  I was able to easily push my wife’s wheel chair all the way to the observation tower.

I heard pig frogs and cricket frogs at this pond, and an eastern kingbird was hunting insects over the water.

Open Okefenokee marshes are called “prairies.”

Spanish moss.  Strange as it may seem, Spanish moss is related to pineapple.

Soft shelled turtle.

The list of animal species I saw on this excursion in less than 90 minutes included alligator, soft shelled turtle, rabbit, pileated woodpecker, barred owl, black vulture, red-winged blackbird, boat-tailed grackle, mourning dove, mockingbird, eastern kingbird, yellowthroat warbler, laughing gull, great egret, black swallowtail butterfly, and at least 4 species of dragonflies.  I heard chimney swifts, pig frogs, and cricket frogs, and raccoon scat littered the boardwalk.  I was surprised I saw just 1 wading bird.  On a previous trip to the Okefenokee I saw none.  I saw the laughing gulls near the county landfill just outside the refuge. I couldn’t determine if the rabbit was a cottontail or marsh rabbit.  It slipped into the palmetto before I could take a photo of it.

Recent Items about the Late Pleistocene in the News

May 10, 2018

3 stories relating to the late Pleistocene recently made the mainstream news.  The first story is about the upcoming resurrection of the woolly mammoth (Mammuthus primigenius).  George Church of Harvard University is using CRISPR technology to genetically engineer a woolly mammoth by editing Asian elephant (Elephas maximus) DNA.  (I explained CRISPR technology in a previous blog entry.  See: https://markgelbart.wordpress.com/2016/07/22/possible-resurrection-of-the-mammoth-as-early-as-2018/  ) Scientists at Church’s lab are going to edit in the phenotypical characteristics that make the woolly mammoth able to survive in cold wet climates with extremely short and long days.  These characteristics include a layer of fat, long oily hair, small ears, the ability to withstand cold temperatures, and adjustments to the circadian rhythms animals that live in the Arctic require.  They think they can produce a genetically engineered woolly mammoth by 2019.  Scientists hope to eventually engineer herds of woolly mammoths that can live in Siberia where their activities will convert the tundra landscape into a grassy steppe.  Ecologists believe a grassy steppe environment will better prevent permafrost from melting, thus mitigating anthropogenic global warming.  I’m all in favor of resurrecting herds of woolly mammoths, but I believe their goal of mitigating global warming is a pipe dream, and I doubt woolly mammoths could survive in the present day tundra.  I suspect woolly mammoths were confined to relic steppe habitat during interglacials.  Climate is a much greater influence on sub-Arctic habitat than the activities of megafauna.  Woolly mammoths could probably survive today on the grassy Tibetan steppes but not in the Siberian tundra.  The mammoth steppe of the late Pleistocene was more like the modern Tibetan highlands than the Siberian tundra.

The 2nd story reported the results of a statistical study that determined the average size of mammal species has declined over the past 130,000 years, and the authors of this study squarely blame man.  Humans have been overhunting large mammals that reproduce slowly to extinction, leaving smaller species that can better replenish their populations with faster breeding.  Rabbits breed faster than mammoths and elephants.  The average size of a North American mammal species during the late Pleistocene was 216 pounds compared with the average North American mammal species of today which weighs 16 pounds. This decline in body size is unprecedented over the past 65 million years and hasn’t occurred since the extinction of the dinosaurs.  The fossil record is pronounced…this statistical study just confirms the obvious.

Evidence humans may or may not have tracked a ground sloth in New Mexico is perhaps the most interesting story.  There are thousands of late Pleistocene-aged animal tracks in the White Sands National Monument.  During the Ice Age weather patterns were different due to altered climate cycles, and southwestern North America was much wetter than it is today.  The site of these tracks, presently a desert, was a lake shore then.  The animals walked on the edge of the lake in the mud and the tracks have been preserved for thousands of years.  Scientists found human tracks adjacent and actually within ground sloth tracks.  Ground sloths usually walked in a straight line, but these tracks appear to show the ground sloth zig-zag, as if it was avoiding a predator.  There are 2 sets of human tracks.  One human was directly following the ground sloth–his steps are inside the ground sloth steps; the other human was walking very gently beside the other person, as if on tiptoe.  The ground sloth circled around and appeared to rise up on its legs and bare its claws.  There are claw marks in the ground too.  Scientists suggest 1 human was distracting the ground sloth, while the other was sneaking up on it to deliver a fatal spear thrust or blow to the head with a club.  The end result is not recorded in the tracks.  Other scientists are skeptical of this interpretation.  Some think it unlikely humans would hunt the sloth in such an open landscape.  However, this site was not as open then as it is today, and humans could easily outpace a ground sloth.

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Human footprint inside sloth print.  The sloth print is 22 inches long.  The human footprint is 5 inches.  The sloth had a wider stride, so the human must have been hopping to get his foot inside the sloth’s print.

I wish there were more mainstream news stories about the late Pleistocene.  It’s much more interesting than waiting for Donald Trump to get impeached.

References:

Daley, J.

“Fossil Tracks May Record Ancient Human Hunting Sloth”

Smithsonian April 20, 2018

Smith, F.; et. al.

“Body Size Downgrading of Mammals over the Late Quaternary”

Science  April 2018

Fish Nest Associates

May 6, 2018

The bluehead chub (Nocomis leptocephalus) is a keystone species in piedmont and mountain rivers and streams of southeastern North America.  Dozens of species of shiners spawn and lay their eggs in bluehead chub nests.  Without the existence of bluehead chubs most of these species would probably become extinct.  Bluehead chubs and shiners are members of the minnow family, known scientifically as the Cyprinidae, and bluehead chubs are 1 of the largest minnow species, growing up to 8 inches long.  Bluehead chubs make large gravel nests and aggressively protect their young.  They bury their eggs with large pieces of gravel and in the process bury and protect the eggs of other minnow species.  A complex ecosystem inhabits bluehead chub nests. Many macroinvertebrates live in bluehead chub nests alongside the minnow eggs.  Snails, clams, and the larval stages of dragonflies, dobsonflies, caddisflies, and beetles use the bluehead chub nests for shelter.  Salamanders and darters prey on the invertebrates entering and exiting the nests.  Scientists believe shiners and bluehead chubs both benefit from the congregation of eggs and hatchling fish, referring to the relationship as mutualism.  The great abundance of eggs from several different species dilutes the losses to predators, and more young of each individual species survives.

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Bluehead chub range map.

Bluehead Chub

Bluehead chub.

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Rainbow shiner (Notropis chrosomus).  Some shiners can get quite colorful.

Many other species of fish associate in the same nests.  Rough shiners (Notropis baileyi), saffron shiners (N. rubicroceus), and greenhead shiners (N. chlorocephalus) spawn in creek chub nests.  Redfin shiners (Lythurus umbratalus) spawn in green sunfish (Lepomis cyonellus) nests.  All of these associations result in increased reproductive success for both species.  Some shiners will use central stoneroller nests, but prefer chub nests and will move their spawning activity to bluehead chub nests, if they become available.

The evolution of fish nest association must be very ancient.  It seems likely the host fish evolved first, and the species of fish using the host’s nest lost their ability to make their own nests when they came into contact with the larger  host species because the host could build bigger nests that offered more protection.  Host species are usually larger and better able to defend the nest than the smaller minnows, but they benefit too from the sudden population explosion of potential food for predators that might otherwise eat their hatchlings.

Reference:

Johnston, Carol

“Nest Associate in Fishes: Evolution of Mutualism”

Behavioral Ecology Sociobiology 35 1994

Swartwout, M.; F. Keating, and E. Frimpas

“A Survey of Macroinvertebrates Colonizing Bluehead Chub Nests in a Virginia Stream”

Journal of Freshwater Ecology 2016