Why mammoths died, new research


This video is called Mammoths of The Ice Age: Discovery Documentary 2015.

From ScienceDaily:

Male mammoths more often fell into ‘natural traps’ and died, DNA evidence suggests

November 2, 2017

Researchers who have sexed 98 woolly mammoth specimens collected from various parts of Siberia have discovered that the fossilized remains more often came from males of the species than females. They speculate that this skewed sex ratio — seven out of every ten specimens examined belonged to males — exists in the fossil record because inexperienced male mammoths more often travelled alone and got themselves killed by falling into natural traps that made their preservation more likely. The findings are reported in Current Biology on November 2.

“Most bones, tusks, and teeth from mammoths and other Ice Age animals haven’t survived,” said Love Dalen of the Swedish Museum of Natural History. “It is highly likely that the remains that are found in Siberia these days have been preserved because they have been buried, and thus protected from weathering. The new findings imply that male mammoths more often died in a way that meant their remains were buried, perhaps by falling through lake ice in winter or getting stuck in bogs.”

“We were very surprised because there was no reason to expect a sex bias in the fossil record,” added Patrícia Pecnerova, the study’s first author, also at the Swedish Museum of Natural History. “Since the ratio of females to males was likely balanced at birth, we had to consider explanations that involved better preservation of male remains.”

The researchers made the discovery in the midst of a larger, long-term effort to examine the genomes of woolly mammoth populations. For some of the analyses, they needed to know the sex of individuals. They initially set out to determine the sex of a small number of mammoths. “It became apparent that we were finding an excess of male samples, which we found very interesting,” Dalen said.

They decided to sex more samples and to examine the sex ratio of individuals collected from the Siberian mainland and from Wrangel Island, off the coast. Overall, they found, males consistently outnumbered females among their samples.

The researchers say the findings suggest that woolly mammoths lived similarly to modern elephants, with herds of females and young elephants led by an experienced adult female. In contrast, they suspect that male mammoths, like elephants, more often lived in bachelor groups or alone and engaged in more risk-taking behavior.

“Without the benefit of living in a herd led by an experienced female, male mammoths may have had a higher risk of dying in natural traps such as bogs, crevices, and lakes,” Dalen said.

The findings highlight the utility of fossil remains for making inferences about the socioecology and behavior of extinct animals, the researchers say. At the same time, they are a reminder to researchers that fossil assemblages don’t necessarily represent a random sample of a population.

The researchers say they’ll continue to study woolly mammoth genomes and those of several other extinct Ice Age mammals. They’re curious to see whether they observe the same skewed sex ratio in other species.

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Saber-toothed cats’ illnesses, new research


This video from the USA is about the La Brea Tar Pits and Natural History Museum and a saber-toothed cat.

From Science News in the USA:

Surgeon aims to diagnose deformities of extinct saber-toothed cats

By Lesley Evans Ogden

9:00am, October 13, 2017

Robert Klapper has examined scores of damaged and diseased human knees, hips and shoulders. But a visit to the La Brea Tar Pits and Museum introduced the orthopedic surgeon to the suffering of an extinct cat — and a scientific mystery. In 2000, Klapper took a break from his patients at Cedars-Sinai Medical Center in Los Angeles to visit the nearby tar pits, where myriad mammals and other animals (SN: 5/17/14, p. 18) have been getting stuck for the last 40,000 years. (Yes, modern birds and insects still wander in).

After examining a museum display of broad-snouted dire wolf (Canis dirus) skulls, Klapper made a beeline for the security guard and asked to see a curator. He badgered then collections manager Chris Shaw with questions about why the skulls looked so perfect — no signs of cancers, fractures or arthritis.

“Instead of throwing me out,” Klapper says, Shaw took Klapper into the bowels of the museum and pulled out a drawer of bones from saber-toothed cats (Smilodon fatalis), one of the abundant prehistoric animals preserved in the pits about 14,000 years ago. Klapper noticed a pelvis with a surface that reminded him of a medieval mace: One hip socket was spiky with sharp edges, a telltale sign of arthritis. At the healthy hip socket, the bone was billiard ball smooth.

That kind of bone damage did not happen overnight. The arthritic animal had been disabled for years, Klapper estimated, perhaps even from birth. The surgeon asked a favor: “I’d love to get a CT scan.” Signing out the ancient cat’s pelvis, he says, was a thrill.

Paleontologists have long debated whether saber-toothed cats were solitary or social hunters. If this lame cat had been unable to hunt for years, which is what its traumatized hip bone indicated to Klapper, it could have survived only with help from other cats.

Klapper scanned that fossilized cat pelvis but left the images untouched for years, occupied with his hospital job and hosting ESPN Radio’s Weekend Warrior, a health and sports program. Now, collaborating with Emily Lindsey, a paleoecologist at La Brea, Klapper plans to use more sophisticated radiology techniques to diagnose the deformity and possibly deduce clues about the cat’s lifestyle.

It’s still early days for the revitalized project, Lindsey cautions, but “I’m really excited about it.” The museum houses some 2,000 fossils of saber-toothed cats, several of which the two plan to scan in the months ahead.

Saber-toothed kittens and other kittens


This video from Los Angeles in California in the USA says about itself:

Saber-toothed cat struts down Wilshire Blvd in L.A. and comes home to the Tar Pits!

On Sept. 5 2012, our Saber-toothed cat took a stroll down to Wilshire Blvd. to announce that Ice Age Encounters will be at the La Brea Tar Pits every Wednesday and Saturday! Our favorite Smilodon even got the CoolHaus ice cream truck to stop by with some delicious Ice Age-themed treats. Ice Age Encounters transports you to the Los Angeles of the Late Pleistocene. While on this journey, you’ll meet the extinct creatures that lived in pre-historic L.A., and witness the natural processes that preserved their remains for thousands of years. You’ll even survive a close encounter with a Saber-Toothed Cat — and meet the scientists who study its fossils at the Page Museum!

By Alan Gilman in the USA:

Saber-toothed kittens may have been born with thicker bones than other contemporary cats

The pattern of bone development for saber-toothed cats mirrors that of contemporary cats

September 28, 2017

Saber-toothed kittens may have been born with thicker bones compared to other contemporary cats, but they have a similar pattern of bone development, according to a study published September 27, 2017 in the open-access journal PLOS ONE by Katherine Long from California State Polytechnic University, USA and colleagues.

Saber-toothed cats (Smilodon fatalis) from the Pleistocene (37,000 to 9,000 years ago) have been previously recognized as having more robust skeletons compared to other wild cats. However, how and when saber-toothed cats developed these strong bones is a mystery.

To better understand the growth of Smilodon bones in comparison to a similar species, Long and colleagues measured and analyzed hundreds of bones at various stages of development from both Smilodon and the contemporary tiger-sized cat Panthera atrox in the La Brea Tar Pits museum.

The researchers found that while Smilodon bones were more robust than the Panthera bones, they did not increase in robustness with age as expected, but were born with more robust bones to begin with. They found that the growth of Smilodon bones followed a similar pattern to other primitive cat species, where the bones actually grow longer and more slender than they grow thick. This finding suggests that the growth and development of feline species is more tightly constrained than previously thought, even with species with very different bone structures.

“Saber-tooth cats had extraordinarily strong front limbs for tackling and subduing prey before they slashed their throats or bellies with their saber-like canine teeth,” says co-author Don Prothero. “Using the extraordinary collection of limb bones of saber-tooth kittens at La Brea tar pits, we found that their limbs don’t become more robust as they grew up, but instead retain the stereotypical growth pattern where the limbs grow longer more quickly than they grow thick. To compensate, saber-tooth kittens were born with unusually robust limbs and retained that pattern as they grew.”

New giant sloth species discovery in Mexico


This video says about itself:

Fossil of New Giant Sloth Species Found in Underwater Cave | National Geographic

31 August 2017

In an underwater cave in the Yucatán in Mexico lie the well-preserved remains of an ancient giant sloth.

The new species is from the late Pleistocene. Its scientific name is Xibalbaonyx oviceps. Its scientific description is here.

Woolly rhinos, why extinct?


This 2013 video is called The End of the Woolly Rhino – Ice Age Giants – Episode 3 Preview – BBC.

From ScienceDaily:

Woolly rhino neck ribs provide clues about their decline and eventual extinction

Fossils point to rare condition in the extinct species, possibly caused by inbreeding and harsh conditions during pregnancy. Monitoring vertebrae in modern rhinos could indicate the level of extinction risk

August 29, 2017

Summary: A study reports on the incidence of abnormal cervical (neck) vertebrae in woolly rhinos, which strongly suggests a vulnerable condition in the species. Given the considerable birth defects that are associated with this condition, the researchers argue it is very possible that developmental abnormalities contributed towards the eventual extinction of these late Pleistocene rhinos.

Researchers from the Naturalis Biodiversity Center in Leiden examined woolly rhino and modern rhino neck vertebrae from several European and American museum collections and noticed that the remains of woolly rhinos from the North Sea often possess a ‘cervical’ (neck) rib — in contrast to modern rhinos.

The study, published in the open access journal PeerJ today, reports on the incidence of abnormal cervical vertebrae in woolly rhinos, which strongly suggests a vulnerable condition in the species. Given the considerable birth defects that are associated with this condition, the researchers argue it is very possible that developmental abnormalities contributed towards the eventual extinction of these late Pleistocene rhinos.

In modern animals, the presence of a ‘cervical rib’ (a rib attached to a cervical vertebra) is an unusual event, and is cause for further investigation. Though the rib itself is relatively harmless, this condition is often associated with inbreeding and adverse environmental conditions during pregnancy.

Frietson Galis, one of the authors of the peer-reviewed study, found a remarkably high percentage of these neck ribs in the woolly mammoth, published in a previous study.

“This aroused our curiosity to also check the woolly rhino, a species that, like the woolly mammoth lived during the late Pleistocene and similarly died out,” said Alexandra van der Geer, one of the authors of the study. “The woolly rhino bones were all dredged from the North Sea and river deltas in the Netherlands. We knew these were just about the last rhinos living there, so we suspected something could be wrong here as well. Our work now shows that there was indeed a problem in the woolly rhino population.”

The absence of cervical ribs in the modern sample is by no means evidence that rhino populations today are healthy. Museum collections are based on rhino specimens that were collected at least five decades ago. Rhinoceros numbers are dwindling extremely fast, especially the last two decades, resulting in near extinction for some species and the total extinction of the western black rhinoceros.

“Our study suggests that monitoring the health of the vertebrae in rhinos has the potential to timely detect developmental errors that indicate the level of extinction risk,” said Frietson Galis.

What Stone Age humans ate


This video says about itself:

26 June 2014

According to the oldest fossil evidence of human feces ever discovered, the extinct species known as Neanderthals probably ate vegetables. Researchers from the University of La Laguna on the Canary Islands in Spain, working along with the Massachusetts Institute of Technology, analyzed fossil samples that include 50 thousand year-old feces from a Neanderthal campfire site close to Alicante, on the coast of the Mediterranean Sea.

Data from the study shows that the Neanderthal diet was mostly meat, but the fossil evidence indicates also the presence of plants in their excrement.

Ainara Sistiaga, a PhD student at the University of La Laguna is quoted as saying: “If you find it in the faeces, you are sure that it was ingested. This molecular fossil is perfect to try to know the proportion of both food sources in a Neanderthal meal.”

Neanderthals are modern humans’ closest extinct relative living between 250 thousand to 40 thousand years ago, and some experts believe that Neanderthals interbred with Homo sapiens before they became extinct.

Experts say that the prehistoric human diet probably varied quite a bit by region and availability, so it is plausible that some populations of Neanderthals ate plants and vegetables.

From the Senckenberg Research Institute and Natural History Museum in Germany:

On the early human’s menu: Mammoth and plenty of raw vegetables

Early modern humans consumed more plants than Neanderthals but ate very little fish

August 4, 2017

Senckenberg scientists have studied the diet of anatomically modern humans. With their recent study, published in the journal Scientific Reports, they were able to refute the theory that the diet of early representatives of Homo sapiens was more flexible than that of Neanderthals. Just like the Neanderthals, our ancestors had mainly mammoth and plants on their plates — the researchers were unable to document fish as part of their diet. Therefore, the international team assumes that the displacement of the Neanderthals was the result of direct competition.

The first representatives of Homo sapiens colonized Europe around 43,000 years ago, replacing the Neanderthals there approximately 3,000 years later. “Many studies examine the question of what led to this displacement — one hypothesis postulates that the diet of the anatomically modern humans was more diverse and flexible and often included fish,” explains Prof. Dr. Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) at the University of Tübingen.

Together with his colleague, Dr. Dorothée Drucker, the biogeologist from Tübingen now set out to get to the bottom of this hypothesis. In conjunction with an international team, he studied the dietary habits of early modern man on the basis of the oldest know fossils from the Buran Kaya caves on the Crimean Peninsula in the Ukraine. “In the course of this study, we examined the finds of early humans in the context of the local fauna,” explains Drucker, and she continues, “Until now, all analyses of the diet of early modern humans were based on isolated discoveries; therefore, they are very difficult to interpret.”

In order to reconstruct our ancestor’s menu — despite the lack of a fossil dietary record — the team around the scientists from Tübingen measured the percentage of stable carbon and nitrogen isotopes in the bones of the early humans and the locally present potential prey animals such as saiga, horses, and deer. In addition, they also analyzed the nitrogen-15 content of individual amino acids, making it possible to not only determine the origin, but also the proportion of the nitrogen. “Our results reveal a very high proportion of the nitrogen isotope 15N in early modern humans,” adds Bocherens, and he continues, “However, contrary to our previous assumptions, these do not originate from the consumption of fish products, but primarily from mammoths.”

And yet another result came as a surprise for the scientists: The proportion of plants in the diet of the anatomically modern humans was significantly higher than in comparable Neanderthal finds — mammoths, on the other hand, appear to have been one of the primary sources of meat in both species.

“According to our results, Neanderthals and the early modern humans were in direct competition in regard to their diet, as well — and it appears that the Neanderthals drew the short straw in this contest,” adds Drucker in conclusion.

This video says about itself:

1 December 2009

Natural History Museum scientists, working as part of the Gibraltar Caves Project, excavated and studied remains of shellfish and other marine animals such as dolphins from two caves in Gibraltar where Neanderthals once lived and have discovered that Neanderthal diets were more like those of early modern humans than previously thought.

Little boy discovers extinct elephant fossil


This video from the USA says about itself:

9-Year-Old Boy Literally Stumbled On A 1.2 Million-Year-Old Stegomastodon Skull

19 July 2017

A 9-year-old boy who was out hiking with his family last November accidentally discovered a rare prehistoric stegomastodon skull in New Mexico’s Las Cruces desert.

From National Geographic in the USA:

Boy Found Million-Year-Old Fossil by Tripping Over It

While walking through the desert near Las Cruces, New Mexico, a now 10-year-old boy stumbled over one of the state’s rarest finds.

Boy Trips While Hiking, Discovers Million-Year-Old Fossil

By Sarah Gibbens

PUBLISHED July 19, 2017

“There are more fossils than I’ll ever be able to count in New Mexico,” said Spencer Lucas, curator of paleontology at the New Mexico Museum of Natural History and Science.

Lucas was commenting on the recent excavation of a fossil found near the Las Cruces, New Mexico, desert last November.

While exploring the region’s Organ Mountains with his parents and two brothers, then 9-year-old Jude Sparks tripped over something protruding from the earth.

In an interview with El Paso ABC affiliate KVIA, Sparks told reporters he immediately revealed the find to his brother, Hunter.

“Hunter said it was just a big fat rotten cow. I didn’t know what it was. I just knew it wasn’t usual.”

The find was in fact not a big fat rotten cow but a stegomastodon, an ancient, primitive mammal that lived an estimated 1.2 million years ago. (Stegomastodons were early tuskers from the animal family Gomphotheres, a distant cousin of ancient mammoths and modern day elephants.)

Later that night, Jude’s parents reached out to New Mexico State University Professor Peter Houde, who they discovered from a previous interview he gave on similar subjects. Houde and the Sparks family returned to the discovery site, finding an entire skull.

After securing funding, finding volunteers, and coordinating when the dig would take place, the university team and the Sparks family returned to the site to excavate the remains. A week after careful excavation, the fragile pieces, which Houde described as “egg-shell thin” to National Geographic.

Houde hopes the fossil will eventually be available for exhibit.

The Fossil State

This isn’t the first time a stegomastodon has been found in New Mexico. In 2014, a bachelor party stumbled across a nearly intact fossil that was collected by the New Mexico Natural History Museum.

Coming across a stegomastodon fossil is considered a rare find. Lucas explained that fossils like those belonging to mammoths are relatively abundant in western portions of North America but for reasons not quite known, stegomastodons are less frequently found. According to Lucas, only a couple hundred have been found in the world.

One theory for why stegomastodons went extinct correlates to the arrival of mammoths.

Lucas’s theory is that the ancient animals couldn’t compete with mammoths. Both animals grazed on their surroundings, and could have competed for resources.

Houde theorized that climate change could have caused the animal’s demise.

“They existed during a time when it was wetter and cooler,” said Houde. “Las Cruces is now a desert.”

Researchers don’t know how many fossils lie buried in the desert, but if they’re to be found anywhere in America, the southwest is a likely location. The region’s naturally dry, rocky terrain create conditions needed to preserve bones for millions of years.

In interviews with local news, the Sparks family speculated that the recent rains in the area before the discovery might have helped to expose the fossil. Lucas agreed that this was well within the realm of possibility. He says that as rain erodes more sediment, discoveries are always possible.

“Erosion is a paleontologist’s best friend.”