Archive for the ‘Pleistocene Mammals’ Category

Snowy Winters and Dry Summers Prevailed in Southwestern North America during the Late Pleistocene

January 26, 2023

Ice Age climates spawned dramatically altered weather patterns compared to those of the present day. The result of those different weather patterns is evident in how changed Southwestern North America has become since then. During Ice Ages Southwestern North America was a land of vast lakes, abundant springs, and widespread wetlands. There even was a lake in Death Valley, California where it almost never rains today. There were especially large lakes in Utah, Nevada, and central Oregon–areas that today are quite arid. Scientists debate the source of the greater precipitation that occurred then. Some think the source was summer rains coming from fronts originating in the tropics, while most believe the polar jet stream carried moisture from the North Pacific that fell as heavy snows during winter. A new study of carbon and oxygen isotope ratios in tooth enamel from Pleistocene mammals supports the latter scenario.

Scientists analyzed 39 teeth from mammoth, bison, horse, and camel excavated from the Tule Spring Fossil Bed National Monument in Nevada. They can determine how precipitation was delivered based on the ratios of carbon and oxygen isotopes in the teeth because the animals ate the plants that absorbed the water, and the animals directly drank it. Most of the precipitation in the region came from heavy snows, and the lakes refilled every spring and early summer from snow melt. They believe summers were relatively dry, and lakes began to evaporate until seasonal snowfall. Mammoths, bison, and horses ate a lot of the fresh grass that grew tall on water from snowmelt. Horses may have eaten more grass here during Ice Ages than they do today. But camels browsed on saltbush (Atriplex sp.). The presence of this species indicates dry summers and arid localities within the lush landscape. Scientists think glaciers to the north of the region split the polar jet stream, and the lower stream carried moisture from the North Pacific, causing winter precipitation. Lake levels were highest during the Last Glacial Maximum following Heinrich Events that occurred when ice dams melted, and massive pulses of freshwater studded with ice bergs flooded into the oceans. Moisture in earth’s atmosphere increased following Heinrich events.

Map of Southwestern North America during the Late Pleistocene. Meltwater from much snowier winters caused the formation of giant lakes in the region then. From the below reference by Munroe and Laabs.
Beth Zaiken’s depiction of wildlife in Nevada during the last Ice Age. Vegetation was much lusher than it is today due to higher annual precipitation.

When glaciers retreated at the end of the Ice Age, the polar jet stream recombined and began to flow to the north. Winter snowfall was greatly reduced, and the lakes gradually evaporated. The Great Salt Lake of Utah is a remnant of a much larger freshwater lake that existed during Ice Ages.

The abundant wetlands and lakes of the region hosted many species of birds that today breed in the Arctic during summer. These species could not live in the Arctic during the Ice Ages because their present-day ranges were under miles of glacial ice. Their breeding ranges shifted to the Southwest. See also:

References:

Kohn, M. et. al.

“Seasonality of Precipitation in the Southwestern U.S. during the Late Pleistocene Inferred from Stable Isotopes in Herbivore Tooth Enamel”

Quaternary Science Review 290 November 2022

Munroe, J.; and B. Laabs

“Temporal Correspondence Between Pluvial Lake High Stands in Southwestern U.S. and Heinrich Event 1”

Journal of Quaternary Science 28 (11) 2013

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The Early-Mid Pleistocene European Jaguar (Panthera gombaszoegensis) was not Actually a Jaguar

January 19, 2023

During 1938 M. Kretzoi, a paleontologist, studied some unidentified lower fossil teeth and concluded they belonged to an extinct species of jaguar that roamed Europe during the early to mid-Pleistocene. He gave the species the scientific name Panthera gombaszoegensis. Paleontologists long thought this species was ancestral to the American jaguar (P. onca) and some thought it was the same species. A mostly complete skull was finally found in a Belgian sinkhole (the La Belle-Roche fossil site) during 1980, but paleontologists didn’t really study it until recently. They compared this fossil skull with those from extant species of cats in the Panthera genus including lion, leopard, tiger, jaguar, and snow leopard. They concluded P. gombaszoegensis was not a jaguar after all, though the lower teeth were similar. Instead, this species was most closely related to the tiger (P. tigris) and based on the characteristics of the skull they believe it was a sister species to the tiger, having diverged directly from the same common ancestor. This makes sense geographically because its range was much closer to the tiger than the jaguar. P. gombaszoegensis lived from 2 million years BP to 350,000 years BP, and it is thought to have been a generalist predator, taking whatever prey species they could bring down. Lions and leopards expanded their ranges into Europe from Africa about 350,000 years ago and likely ecologically replaced P. gombaszoegensis.

Map showing range of modern tigers, modern jaguars, and the extinct Panthera gombaszoegensis. An anatomical comparison concludes European jaguars were more closely related to modern tigers than jaguars. This makes more sense geographically. The lower image is a map showing fossil localities where this species has been found in Belgium. Image from the below reference.

Skull of Panthera gombaszoegensis. A comparison of this skull with extant species of cats in the Panthera genus suggest it is a sister species of modern tigers, not jaguars. Image also from the below reference.

Paleontologists think the Panthera genus originated in central Asia about 6 million years ago during the late Miocene. The direct ancestor of the jaguar is unknown. The oldest jaguar fossil known was found in a cave in West Virginia and dates to 850,000 years ago. It descended from a species that crossed the Bering land bridge sometime during the early Pleistocene.

Reference:

Chator, N.; M, Michaud, and V. Fischer

“Not a Jaguar After All: Phylogenetic Affinities and Morphology of the Pleistocene Felid Panthera gombaszoegensis

Papers in Paleontology 2022

link https://www.researchgate.net/publication/363739515_Not_a_jaguar_after_all_Phylogenetic_affinities_and_morphology_of_the_Pleistocene_felid_Panthera_gombaszoegensis

Pleistocene Howls

January 5, 2023

Hyoid bones are rarely found in most fossil sites. Canid hyoid bones are a collection of 9 small bones held together with ligaments. The hyoid bone supports the pharynx, larynx, and tongue. During the process of decomposition after an animal dies, the larger bones are more likely to be preserved, but the small bones such as the ones that make up the hyoid get separated and oftentimes crushed. They then dissolve or are broken into unrecognizable fragments. However, the La Brea tar pits are an exceptional fossil site with excellent preservation, and many complete hyoid bones have been found there. Scientists recently studied the canid hyoid bones found there and compared them to the hyoid bones found in extant species of coyotes and wolves.

Diagram of a dire wolf hyoid bone from the below reference.
Illustration by Mauricio Anton. During the Pleistocene big cats mostly hunted in forested areas while dire wolves mostly hunted in open areas.

Dire wolves had larger hyoid bones than modern species of wolves including gray and red wolves and coyotes. They howled with a lower frequency and deeper pitch than any species of extant American wolf. Scientists couldn’t find any difference between the hyoid bones of coyotes and red wolves. Pleistocene coyotes were larger than modern coyotes and so were their hyoid bones. They howled with a lower frequency and deeper pitch than modern coyotes. If we could hear a dire wolf howl, we would definitely notice a much deeper howl than normally heard today by people lucky enough to live where wolves and coyotes’ howl.

Reference:

Flores, D., E. Eldridge, E. Eliminowski, E. Dickinson, A. Hartstone-Rose

“The Howl of Rancho La Brea: Comparative anatomy of Modern and Fossil Canid Hyoid Bones”

Journal of Morphology April 2020

https://www.researchgate.net/publication/340726915_The_howl_of_Rancho_La_Brea_Comparative_anatomy_of_modern_and_fossil_canid_hyoid_bones

All Modern Wolves (Canis lupus) Descend from a Population that Originated in Beringia

December 29, 2022

All wolves in the northern hemisphere descend from a population originating in Beringia, according to a recent study of wolf DNA. Beringia is the geographic region including western Alaska, eastern Siberia, and formerly the Bering land bridge when it was above sea level during Ice Ages. Scientists examined the DNA from 90 “modern” wolf specimens (those dating to less than 500 years old and 40 “ancient” wolf specimens (those dating to more than 500 years old). They concluded the population of wolves living in Beringia 50,000 years ago eventually expanded across Eurasia and North America and displaced the populations of wolves that were already living there. Ice sheets blocked expansion into North America until about 15,000 years ago. There is not enough data to know for sure how similar Beringian wolves were to North America wolves living below the Ice Sheet before the expansion.

Graph showing expansion of the Beringian wolf population across the Northern Hemisphere during the Late Pleistocene. From the below referenced paper.

Late Pleistocene wolves were larger and had teeth, skulls, and jaws that were more robust than modern gray wolves, though they were not as robust as those of the extinct dire wolves (C. dirus) formerly found throughout most of North America. Dire wolves were not at all closely related to gray wolves and were separated by at least 1 million years of evolutionary divergence. Late Pleistocene wolves were well adapted to scavenging and/or hunting mammoths, horses, and bison. The population of wolves from Beringia may have specialized in hunting caribou and perhaps followed caribou herds over long distances. Maybe this explains how they became so widespread. The other wolves, so well adapted to hunting megafauna, didn’t survive megafauna extinctions, but Beringian wolves following caribou herds did.

The results of this recent study contradict an older study that concluded modern gray wolves didn’t descend from the more robust Beringian wolves. The authors of the newer paper explain their study had a greater sample size and looked at more of the wolf DNA than the older study did. It certainly eliminates the mystery of where modern Alaskan wolves originated. They’ve had a continuous presence in the region for a very long time.

Reference:

Loog, Lisa, et. al.

“Ancient DNA Suggests Modern Wolves Track their Origin to a Late Pleistocene Expansion from Beringia”

Molecular Ecology Jan 2020

https://onlinelibrary.wiley.com/doi/full/10.1111/mec.15329

Mammoth Populations Decreased While Horse Populations Increased in Europe during the Late Pleistocene

December 22, 2022

Anatomically modern humans hunted mammoths in Europe over 34,000 years ago. There is plenty of archaeological evidence for this, but the evidence gets scarcer after this date. A recent study places the blame for this decline in mammoth populations on humans. Scientists analyzed the chemical isotope ratios in the bones of mammoths, horse, red deer, caribou, and wolf from a time period dating between 34,000 years BP-23,000 years BP. They determined the environment favorable to mammoths remained intact during the time period, yet mammoth populations declined significantly. Climatic changes were minimal. Therefore, the only explanation for this decline in mammoth populations was overhunting by humans. People likely decimated populations by focusing on the juvenile individuals. This might also explain the scarcity of the scimitar-toothed cat in the fossil record after this date in Europe. The scimitar-toothed cat specialized in hunting juvenile mammoths, and their decline coincided with the decline of their prey.

A scientific study determined mammoth populations in Western Europe declined beginning about 34,000 years ago. Scientists believe overhunting by humans “decimated mammoth populations.” Horse populations increased during this time period because more food became available for them when there were fewer mammoths. The environment remained stable during this time period.

This study found a great overlap in the diets of mammoths and horses. More food was available for horses following the decline of mammoth populations, and horse populations increased during this time period. Eventually though, humans overhunted horses too. The bones used from this study were from Germany and France, and it was an extensive study with a large sample size. It shows how humans impacted landscapes even before we were common.

Reference:

Drucker, D.; et. al.

“Tracking Possible Decline of Woolly Mammoth during the Gravettian in Dordogne (France) and the Ach Valley (Germany) Using Multi-Isotope Tracking (13 C, 14 C, 15 N, 34 S, 18 O)”

Quaternary International Mar 2016

Missing Pieces of the Ecosystem

October 6, 2022

The extinctions of Pleistocene megafauna had a profound impact on ecosystems. Large herds of megafauna with the exception of bison were no longer foraging, trampling, and defecating on the landscape in North America. Plant communities were altered, and many predators and scavengers disappeared when all that meat was no longer available. A new study of fossil bones from sites located in the Edward’s Plateau, Texas examined some of the changes in the surviving fauna following the extinction of late Pleistocene megafauna. The authors of this study looked at bone chemistry to determine diet of species before and after extinctions, and they also estimated average size based on fossil remains (in some cases just the teeth). (I should note studies based on stable isotope analysis should be viewed with caution. See: https://markgelbart.wordpress.com/2016/06/24/trust-the-coprolites-not-the-stable-isotope-analysis/ )

Edward’s Plateau, Texas. Study area of the below reference.

The Edward’s Plateau is located in the middle of the North American continent and hosted species from the West, East, and those that had a continental distribution. During the Pleistocene there were grazers, browsers, and mixed feeders. Grazers included mammoths, bison, and horses. Browsers included mastodon, deer, pronghorn, tapir, llama, rabbits, and hare (jackrabbit). Gompotheres, camels, and peccaries were mixed feeders. The authors of this study could not obtain data from ground sloths, glyptodonts, and helmeted musk-ox to determine what they ate. Scientists found saber-toothed cats (Smilodon fatalis) and scimitar-toothed cats (Homotherium latidens) both had a specialized diet of juvenile grazers that were still nursing. These predators fed mostly upon young mammoths and bison that were still dependent upon their mother’s milk. Elephants lactate for up to 3 years after giving birth. Still nursing mammoths faced danger when they wandered away from the safety of the herd. Giant lions (Panthera atrox) and dire wolves (Canis dirus) had more generalist diets, eating grazers and mixed feeders. Black bears mostly ate plants. The lone specimen of giant short-faced bear (Arctodus simus) in this study had a diet similar to the striped skunk. Strange as it might seem, this giant bear was eating insects, mice, and fruit. Jaguars replaced other large Pleistocene predators as the main predator of juvenile bison and horses, following the extinctions of proboscideans, saber-tooths, giant lions, and dire wolves, but only for a short period of time. Horses are absent in the fossil record during the early Holocene, but this study and others suggest they lingered for a while after other Pleistocene megafauna went extinct. Eventually, jaguars become absent in the fossil record of this region, though historical accounts indicated they occurred as far east as Louisiana into historical times. They probably occurred in low numbers in this region. Cougars, formerly absent in the fossil record from this region, became more common.

In the Edwards Plateau, Texas jaguars temporarily replaced saber-toothed cats as a predator of juvenile bison and horses during the early Holocene about 10,000 years ago. Jaguars eventually became rare in this region too. Chart from the below referenced paper.

After the extinction of Pleistocene megafauna surviving herbivores responded differently. Deer and hare became larger, while cottontail rabbits and bison grew smaller. Hares and rabbits shifted to a diet of plants preferred by grazers.

Reference:

Smith, F., E. Elliot Smith, A. Villegenor

“Late Pleistocene Megafauna Extinction Leads to Missing Pieces of Ecological Space in North American Mammal Community”

PNAS 119 (39) September 2022

Goodbye Right Molar #2, Hello Legal Pot Dispensaries in Georgia

September 22, 2022

The dentist and the dental hygienist were shocked my right molar didn’t hurt when I went for my first teeth cleaning in 10 years. It used to hurt. In 1998 my old dentist filled a large cavity and told me he didn’t think the filling would last 6 months, and I would eventually require a root canal. I’d heard nothing but bad things about root canals, and I began flossing regularly. The tooth endured with no change for 20 years, though it occasionally ached. One evening, I was watching The Walking Dead television show, while snacking on corn chips. I started digging what I mistakenly thought were chewed up corn chips stuck in my right molar, and I pulled out most of that dental work. My right molar never hurt again. By odd coincidence, I later learned my old dentist died suddenly in his office that same week. My new dentist took one look at this molar and said extraction was the only option–not even root canal could save it. I scheduled an appointment to have it removed, but 10 days before this date, it became loose and fell out when I flossed. If I didn’t already have an appointment, I’d leave that spot alone, but the dentist will still want to remove the roots to prevent infection. This procedure shouldn’t be a big deal. He’ll numb the area and use forceps to wiggle the roots free.

I want to keep the rest of my teeth and that means regular visits to the dentist. Like a kid, I need an incentive. Kids get candy for being good, so I’m going to give myself adult candy and visit a local cbd smoke shop every time I have a dental appointment. Stores that sell cannabis products are now offering Delta-8 cbd. Illegal marijuana is Delta-9, but chemists use isomerization to change Delta-9 to Delta-8. Delta-8 has the exact same chemical composition as Delta-9, but it has a different structure, so technically it is legal. I wasn’t impressed the first time I tried Delta-8–the high was mild and short-lived. However, smoke shops and convenience stores that sell Delta-8 are not regulated at all, and I believe some of the Delta-8 products they sell have considerable amounts of residual Delta-9. Last time I tried it, I could not tell the difference. The FDA warns there have been hundreds of people who have gone to emergency rooms across the country after consuming Delta-8, but this is out of tens of millions of users. Those people were probably not used to getting high or simply suffered unwarranted paranoia–a side effect of marijuana consumption. I don’t think state authorities are eager to crack down on cbd shops. I think they don’t want people from Georgia traveling to other states to purchase recreational pot because it means lost tax revenue. So pot is basically legal here now.

Honest, I wasn’t high when this thought occurred to me. What if the human race became extinct, and the only evidence left of our existence was my broken tooth pictured above? How would alien paleontologists exploring our planet imagine what we looked like based on 1 broken tooth? The only evidence of the existence of an extinct ape known as Gigantopithecus blacki is about 60 teeth–no other skeletal remains have been found. This species is thought to have lived from 2 million years BP-300,000 years BP. They lived in jungle environments with acid soils where fossil preservation is rare. Their teeth were found in caves with the remains of stegodon, rhino, tapir, goat, deer, ancestral tiger, hyena, dhole, and bear. Scientists believe they ate forest plants, especially fruit. 15 of the 62 teeth found so far have tooth decay. This species could have used a dentist. Scientists think its closest living relative was the orangutan, but it is believed to have been much larger. In my opinion artists’ depictions are quite fanciful, based on wild guessing.

Paleontologists imagine Gigantopithicus looked like this. The only fossil evidence of this species is some 60 odd teeth. I think this reconstruction is a stretch.

Pleistocene Paw, Hoof, and Footprints in New Mexico (redux)

August 17, 2022

I already wrote an article with this title 2 years ago, but a minor disaster last week inspired me to rewrite it. In the original article I wrote the fossilized human footprints found at White Sands National Park were at least 11,000 years old. A new study published last year determined the footprints were between 23,000 years-21,000 years old. I tried to edit in a note to the old article explaining the results of the new study, and some kind of glitch erased the last 2 paragraphs and the image I used for the original article. I could look for the old handwritten first draft in a stack of old notebooks I keep in a dusty, old, cardboard box, then retype it, but I decided to start all over and rewrite it completely.

During the late Pleistocene climate patterns were much different in the American Southwest than they are today. The region enjoyed higher rainfall and a cooler more temperate climate, resulting in abundant lakes. Lake Otero, now a completely dry lakebed, was filled with water then and surrounded with lush prairie and scattered trees. A drier climate phase struck, and the lake began to recede, leaving a muddy shoreline where many species of mammals left trackways, including humans, mammoths, camels, bison, Harlan’s ground sloths, saber-toothed cats, giant lions, and dire wolves. Some of the human trackways crisscross those of a ground sloth, and it appears as if the sloth paused and stood, so the animal could better detect the human scent. 61 fossilized human footprints have been found here, and they are mostly of teenagers and children. Apparently, the teenagers were going back and forth, as if they were carrying objects. Children appear to be playing. Scientists hypothesize the adults were fishing and/or collecting edible aquatic plants, and the teens were carrying the items to a camp (not yet found by archaeologists). One teenager was babysitting a toddler and carrying it around.

Human trackways at White Sands National Park in New Mexico. Some scientists estimate these footprints are about 21,000 years old. Human trackways are interspersed with the prints of Pleistocene megafauna.
Artist’s rendition of White Sands National Park 21,000 years ago. Image is a courtesy of the National Park Service.

Of course, fossilized footprints can’t be radiocarbon dated, so how did scientists date the trackways? They radiocarbon dated the ditch grass (Ruppia cirrhosa) seeds found in sediment above and below where the trackways are located. They determined the trackways are between 23,000 years BP-21,000 years BP. This evidence contradicts mainstream archaeologists who believe humans didn’t arrive in North America until about 14,000 years ago.

Diagram showing how the conclusions by the above discussed study could be wrong. Gary Haynes believes wind erosion redeposited older sediment over younger sediment or simply displaced younger sediment so 21,000-year-old ditch grass seeds were on the surface when men and megafauna walked in the area 13,000 years ago. Image from the below reference (Haynes 2022).

Gary Haynes, a renowned archaeologist, casts doubt on the purported age of the trackways. In an article he published in the journal PaleoAmerica, he points out 3 factors that could cause the scientists to reach misleading conclusions about the age of the trackways. The presence of hardwater in an environment causes radiocarbon dates to be older than they actually are. The scientists who dated the trackways were aware of this but think this isn’t a problem because local water is currently not hard. However, Haynes points out they didn’t analyze modern ditch grass to see if it absorbs a greater concentration of hard water than is found in the environment. Another factor that could cause misleading dates is redeposition of sandy sediment by wind. One study of a stratigraphic column in the area nearby found roughly half of the dates were out of order with older sediment on top of younger sediment and alternating with it. Haynes thinks the stratigraphic column in the region where the trackways are found date to between 15,000 years BP-11,000 years BP, dates consistent with when the Clovis culture was known to occur in North America. Finally, he thinks the trackways were made 13,000 years ago, but the exposed sediment where the humans and animals walked happened to be older due to wind redeposition. In other words wind blew the younger sediment away, and people and animals were walking on old sediment.

M. Bennett is the lead author of the study determining the trackways were 21,000 years old. His response to Haynes’s alternative explanation was short and rather obtuse. He believes it was unlikely redeposition of windblown sand occurred, but he offers no explanation why. He also stated the trackways couldn’t be of Holocene age because the human trackways were interspersed with Pleistocene megafauna trackways, and Pleistocene megafauna were extinct by the Holocene (beginning about 11,000 years ago). However, Haynes merely quoted another study that mentioned the trackways being of Holocene age was just 1 of 3 possibilities. Bennett didn’t even address Haynes’s belief that the trackways date to 13,000 years BP when Pleistocene megafauna still roamed the region.

References:

Bennett, M. , et. al.

“Evidence of Humans in North America during the Last Glacial Maximum”

Science 373 6562 2021

Haynes, G.

“Evidence for Humans at White Sands National Park during the Last Glacial Maximum could be for Clovis People ~13,000 years ago”

PaloeAmerica March 2022

Aborigines may have Occurred in South America and Southwestern North America Before the Last Glacial Maximum

August 10, 2022

There is tantalizing genetic and archaeological evidence suggesting small ephemeral populations of people related to Australian aborigines occupied parts of South America and southwestern North America thousands of years before Amerindians colonized the continents. The archaeological evidence predates or at some sites is simultaneous with the Last Glacial Maximum, the climate phase when the most recent Ice Age glaciers reached their greatest extent about 21,000 years ago. Mainstream archaeologists long believed the first humans arrived in the Americas about 14,000 years ago, but there are just too many compelling archaeological sites, especially in South America and southwestern North America, that contradict this view. The radio-carbon dates can’t be wrong on all of them. Examples of archaeological sites predating or simultaneous with the Last Glacial Maximum include Monte Verde, Chile (33,000 years BP), Toca de Tara Peia, Brazil (20,000 years BP), Arroyo del Vizcaina, Uruguay (30,000 years BP), fossil footprints in Argentina (30,000 years BP), Chiquihuite Cave, Mexico (26,000 years-19,000 years BP), Conxcatlan Cave, Mexico (30,000 years BP) and fossil footprints in New Mexico (21,000 years BP). Now, a recent study of a site in New Mexico determined humans butchered a mammoth and calf here 37,000 years ago.

The recently studied site located in New Mexico is known as the Harley Mammoth Locality named after the hiker who found it. Scientists examined the mammoth bones using CAT scans and determined the mammoths were butchered by humans. The skulls were broken to extract the calorie-rich brains. Ribs were removed from vertebrae–a logical step when breaking down a large mammal. Calorie-rich marrow was extracted from the bones as well. 6 chert flakes, debitage from toolmaking, were found in situ. And it appears as if some of the bones were used for fuel to cook fish over open campfires. Fish scales were found, though the site is 70 yards from the nearest source of water. There is no sign of carnivore scavenging, but the scientists did find termite and cicada burrows in the bones. Insects likely burrowed into the bones after they were slowly buried when rain over time washed sediment downslope over the bones. Later, wind eroded some of this sediment away, allowing Hartley to find some of this material.

Stones modified by tool-making found at the Hartley Mammoth Site dated to an incredible 37,000 years BP. Image from the below reference.
Mammoth bones with evidence of human butchering. From the Hartley Mammoth Site located in New Mexico. Image also from the below reference.

3 Indian tribes found in the Amazon Basin, including the Surui, Karitiana, and Xavanti, have a genetic marker suggesting some of their ancestry is related to the ancestors of Australian aborigines. This genetic marker is known as the Y population and is found in no other known populations of Indian tribes. The oldest known human skeleton in the Americas, the Anzick child from South Dakota, dates to about 12,900 years ago and does not have this genetic marker. This genetic evidence suggests 2 different populations colonized the Americas. Aborigines colonized Australia about 40,000 years ago, and it seems likely they were capable of long-distance sea travel then–a knowledge that was lost over time. Small groups of them may have discovered South America at about the same time their relatives found Australia. Maybe, they were so traumatized by harrowing sea journeys, they decided to stick to land, and over a generation they forgot how to travel by sea. I hypothesize populations of aborigines in America remained low over millennia and likely were always on the verge of extinction in the harsh environments of the Late Pleistocene. The later invasion of more technologically advanced Indians probably displaced the aborigines across most of their range with the exception of the Amazon Basin where they interbred. Perhaps, Indians were more dependent upon aborigine knowledge in the more challenging environment of the Amazon jungle.

3 tribes in the Amazon basin have a genetic signature shared with Australian aborigines. No other Indian tribes in the Americas have this signature. These tribes may be relics from a more widespread population that was displaced by Indians during the Late Pleistocene. Linguistic evidence also suggests the former existence of aborigines alongside Amerindians.

Apparently, aborigines didn’t have as negative an impact on megafauna populations as the Indians. They were fewer in number and never specialized in hunting megafauna, though they did occasionally kill large animals. They probably preferred exploiting small game and fish because it was less risky. Small aborigine tribes couldn’t risk casualties when hunting larger more dangerous animals.

Reference:

Rowe, T. et. al.

“Human Occupation of the North American Colorado Plateau ~37,000 years ago”

Frontiers of Ecology and Evolution July 2022

https://www.frontiersin.org/articles/10.3389/fevo.2022.903795/full#S12

The Yturria Ranch in Southeast Texas

July 6, 2022

Some of the best places to see wild megafauna are areas managed by humans. The Yturria Ranch, located in southeast Texas, is a good example of a wildlife haven enhanced by people. During 1849 Francisco Yturria inherited his wife’s land grant and became the owner of 312 square miles. He made a smart decision shortly after the Mexican War and sided with local white people (the winning side) in their dispute with Hispanic partisans who wanted to take land back for Mexicans. This cemented his claim on the land. Today, Richard Butler, a 5th generation descendent of Yturria, owns the ranch, though it has been whittled down to 22 square miles. Still, it is so big it has its own railroad stop. It has always been a working cattle ranch, but now much of the ranch’s revenue comes from offering hunters the chance to shoot exotic big game. The land here has been improved by wildlife managers to help support native species and the introduced populations of African and Indian antelopes that make the ranch an impressive refuge for megafauna.

Tractors are used to disc the land, a process that disturbs the soil and increases the variety of plant species able to thrive, thus providing a wide range of food for animals. Wells and manmade water tanks attract thirsty wildlife. And ranch managers are working to restore native Tamaulipas thorn scrub, a type of environment with dry soils high in calcium. Mesquite, plateau live oak, cenizo, acacia, Texas ebony, Texas persimmon, yucca, and a variety of unusual forbs and grasses grow on Tamaulipas thorn scrub land. Other environments found on the ranch include coastal savannah, live oak forests, mesquite groves, pastures, and wetlands.

The ranch is rich in native and nonnative megafauna populations. In addition to white tail deer and collared peccary, hunters seek out African waterbuck, oryx, and lechwe or Indian blackbuck and nilgai antelope. Feral hogs must also be abundant, though not advertised (hunters can kill them just about anywhere). Zebras roam the ranch too. Predators living on the ranch include coyote, cougar, bobcat, and ocelot. Ranch managers participate in ocelot conservation. This species is uncommon on this side of the Rio Grande. The ranch hosts more species of megafauna today than have been found here since the late Pleistocene, at least 12,000 years ago. The ranch supports healthy populations of turkey and quail. Caracaras, roadrunners, and species of birds that prefer scarce human populations nest on the ranch.

The Yturria Ranch is a vast wilderness.
Herd of endangered oryx antelope on the Yturria Ranch.
Blackbuck antelope, native to India, abound on the Yturria Ranch.

It costs $1500 a night to stay on the ranch, and there is a 2-day minimum. Hunters with the urge to kill exotic animals are probably the most frequent guests, but one doesn’t have to be a hunter to stay here. Guided fishing trips and bird tours led by professional ornithologists are offered. I’d be happy just to take a walk and photograph any wildlife I encountered. I briefly fantasized about living in the area. The ranch spans parts of 2 counties, but from a satellite view it looks like there is just 1 suburban residential development in the area, and shopping centers are scarce. However, San Antonio looks to be about an hour away, and Padre Island beach is about 30 minutes away. New Orleans is a day’s drive. Climate is subtropical and grapefruit are grown nearby. I wonder if beef prices are cheaper here because it is close to the source. I think this region is a pretty nice choice for retirees.