3 species of human ancestors may have mixed and mingled in one Siberian cave 45,000 years ago – altering our evolution

denisova cave
The Denisova cave in Russia’s Anui River Valley.

Denisova Cave, high in the mountains of Siberia, was a happening place for our ancestors 300,000 years ago. Anthropologists have known that for a while: Scientists have excavated bones and teeth there from our Neanderthal and Denisovan cousins – and one of their hybrid children – over the last two decades. They’ve also found stone tools and jewelry.

But according to a recent study in the journal Nature, modern humans appear to have joined the party, too.

An analysis of ancient DNA culled from sediment on the cave floor suggests that these Homo sapiens occupied the cave starting around 45,000 years ago. So they may have overlapped with Neanderthals and Denisovans.

“We now have the first direct evidence for the presence of ancient modern humans at the site,” Elena Zavala, an evolutionary anthropologist at the Max Planck Institute in Germany and a co-author of the study, told Insider.

Neanderthal Evolution
An exhibit shows the life of a Neanderthal family at the Neanderthal Museum in the town of Krapina, Croatia, February 25, 2010.

The findings offer further insight into how our human ancestors interacted and interbred – exchanging genes and tool-making technology that altered the course of our species’ evolution.

“I cannot think of another site where three human species lived through time,” Katerina Douka, an archaeologist who was not involved in the study, told Science.

Ancient DNA tells a 300,000-year story

Zavala’s team collected more than 700 soil samples between 300,000 and 20,000 years old from across the cave’s three chambers.

One-quarter of those samples contained hominin DNA from microscopic bits of human skin, hair, and poop that got mixed into the sediment. The researchers also found DNA from ancient dogs, bears, hyenas, and horses.

denisovan mtDNA lab work
A scientist analyzes ancient DNA in a laboratory at the Max Planck Institute for Evolutionary Anthropology.

From their extensive DNA analysis, they were able to piece together a timeline of the cave’s occupants. Starting about 250,000 years ago, during a period of global warming, Denisovans started using the cave. Then roughly 60,000 years later, as the climate shifted and temperatures started to drop, Neanderthals arrived on scene.

The two hominins shared the cave for another 60,000 years before traces of the Denisovans disappeared from the fossil record.

For 30,000 years, Neanderthals were the cave’s sole occupants. After that, the new study reveals, a second population of Denisovans emerged. That happened about 100,000 years ago, at the start of the last global ice age. DNA evidence suggests both these Denisovans and their Neanderthal cave-mates survived for up to 78,000 years more.

That’s an important part of the timeline, according to the study, because it suggests those two hominin groups were still thriving in Denisova Cave when the first Homo sapiens showed up 45,000 years ago.

denisova cave
Layers of sediment on the walls of the Denisova Cave.

The team found DNA from all three species in a layer of soil that’s between 45,000 and 22,000 years old – which suggests they all overlapped.

A meeting point for hominins

denisovan
A portrait of a young female Denisovan based on a skeletal profile reconstructed from ancient DNA.

The fact that three hominin species all chose the same cave got Zavala thinking: What made this spot so special?

“It’s interesting that Denisovans and Neanderthals kept returning to the cave because it is located at the edge of what is thought to be each of their geographical ranges,” she said. (Neanderthals were predominantly from Europe, and Denisovans from Asia.)

Most likely, according to Zavala, it sat along a migration route between Europe and Asia.

“This cave was repeatedly meeting point between these two regions,” she said.

But to verify this idea, anthropologists would need to find more sites along this potential migratory path.

denisova cave
A view from the Denisova Cave in Russia.

Zavala thinks excavators will continue to find more traces of hominin and animal occupants in Denisova Cave.

Previously, anthropologists had to rely on fossils to assess which ancient species were present in an area. But pulling DNA straight from the soil has increased the amount of evidence scientists have to work with, thereby making findings like Zavala’s possible.

“We are not limited by the rare discovery of skeletal materials,” she said.

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The dinosaurs may have already been going extinct before the cataclysmic space rock hit Earth, new findings suggest

dinosaur asteroid meteor
An artist’s depiction of the moment the Chicxulub asteroid struck present-day Mexico 66 million years ago.

It’s tempting to ponder what life on Earth might have looked like had a space rock not hit 66 million years ago. That impact in present-day Mexico doomed the dinosaurs and a majority of land and marine species. In its absence, would humans and other mammals have eventually duked it out with T. rex and triceratops?

The answer is probably not, according to a study published Tuesday.

That research found that six major groups of dinosaurs were slowly going extinct over the 10 million years prior to the crash. The impact’s consequences – mile-high tsunamis, raging fires, and a choking cloud of thick dust and sulfur that blotted out the sun – were merely a nail in the dinosaurs’ coffin.

“The meteorite is seen as a coup de grâce for dinosaurs, which finished them off,” Fabien Condamine, a research scientist at the University of Montpellier in France who co-authored the new study, told Insider.

Condamine and his collaborators suggest that a period of global cooling may have contributed to a decline in the overall number of dinosaur species, which then made it impossible for the animals to recover after the cataclysmic event.

“Many paleontologists think dinosaurs would have continued to live if the asteroid did not hit Earth. Our study brings new information for this question, and it seems that dinosaurs were not in good shape before the impact,” Condamine said.

Dinosaurs were already on their way out

T. rex
A full-grown Tyrannosaurus rex weighed between 6 and 9 tons and was up to 43 feet long.

The researchers behind the new study looked at 1,600 fossils from 247 dinosaur species that lived during the late Cretaceous period – from about 100 million to 66 million years ago. That group includes two-legged carnivores like the T. rex, triceratops, and duck-billed dinosaurs.

The team grouped them into six large families, then analyzed how the diversity of species in those families changed over time. The results show that across all six groups, the number of species started to gradually decline 76 million years ago, prior to the space-rock impact.

“We do not find that dinosaur diversity was high and diversifying toward the end of the Cretaceous, as previously thought,” Condamine said.

His isn’t the first group of scientists to suggest that dinosaurs actually went extinct gradually. A 2016 study found that as species of dinosaurs that had been around on Earth a while went extinct, no newer species replaced them. Although questions lingered as to whether that conclusion was simply the product of an incomplete fossil record, this new study shows that older species did indeed have higher extinction rates than younger ones.

An herbivore monopoly

Arctic dinosaur hadrosaur
A painting of Ugrunaaluk kuukpikensis, a species of duck-billed dinosaur that lived during the Cretaceous period.

In the late Cretaceous period, the planet began to cool: Starting 80 million years ago, global temperatures dropped by about 13 degrees Fahrenheit (7 degrees Celsius).

Given that dinosaurs relied on the temperature of their environment to regulate their body heat, Condamine said, that change in climate might have played a role in their extinction rates.

“Warm periods favored dinosaur diversification whereas cooler periods led to enhanced extinctions,” the study authors wrote.

Another possible explanation for the dinosaurs’ decline is a change in the number of herbivore species in the ecosystem. Hadrosaurs, or duck-billed herbivores, seem to have dominated between 76 million and 66 million years ago – out-competing their fellow leaf-eaters like triceratops and the clubbed-tailed, armored ankylosaurs. That contributed to the decline of those other herbivores.

“Removing herbivores can make the entire ecosystems more prone to extinction cascades,” Condamine said.

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‘Dragon Man,’ a mysterious new human species found in China, could be a closer relative of ours than Neanderthals

Homo longi dragon man
An artist’s concept of Homo longi, or “Dragon Man.”

About 146,000 years ago, a hunter died in the forests of what is now northern China. His skull remained almost perfectly preserved in sediment until bridge builders in Harbin found it in 1933.

At that time, Harbin was occupied by Japan, so a Chinese worker hid the skull in an abandoned well, where it remained for 85 years. The worker told his grandson about the hidden bone, now known as the Harbin cranium, and three years ago it finally made its way to anthropologists at the Hebei GEO University.

A trio of papers published Friday reveal that the skull belonged to a previously unknown species of human ancestor, called Homo longi.

“Because the Harbin fossil is so well preserved and informative, it is one of the most important finds so far for the last 500,000 years of human evolution,” Chris Stringer, an anthropologist at the Natural History Museum in London who co-authored the studies, told Insider.

Stringer’s team nicknamed this new hominin species “Dragon Man,” after the province where it was found: Heilongjiang, which translates to “dragon river.”

According to the new research, “Dragon Man” could be the closest known relative of modern humans – closer than Neanderthals, the group to which that title previously belonged.

‘Dragon Man’ might have interbred with ancient humans

Homo longi dragon man
Skulls of different human ancestors uncovered in China so far – the “Dragon Man” skull is on the far right.

According to the new studies, the Harbin cranium came from a 50-year-old male. The analysis also showed that Homo longi had a brain size comparable to that of modern humans, though parts of its skull resemble those of more ancient hominins.

As shown in the video below, Homo longi’s skull is massive and has a flatter shape, with square eye sockets, thick eyebrow ridges, and oversized teeth. These are characteristics more typical of Neanderthals, and they suggest that “Dragon Man” was relatively large. From the skull’s size, researchers think the species had adapted to survive in harsh environments.

“Like Homo sapiens, they hunted mammals and birds, and gathered fruits and vegetables, and perhaps even caught fish,” Xijun Ni, a paleoanthropologist at the Hebei GEO University who co-authored the studies, said in a release.

During the period 146,000 years ago, known as the Middle Pleistocene, various human ancestors crossed back and forth between Africa, Asia, and Europe. Modern humans were already living in western Asia, including the Arabian Peninsula, so in their eastern migration, they could have crossed paths with the “Dragon Man.”

“We don’t know if this population survived long enough to meet Homo sapiens, but they may well have done. If Neanderthals could interbreed with modern humans, then I’m sure that the Harbin group could too,” Stringer said.

Humanity’s closest relative?

Neanderthal
An employee of the Natural History Museum in London looks at model of a Neanderthal male in September 2014.

To determine whether Homo longi was more like Homo sapiens or Neanderthals, the researchers measured more than 600 parts of the Harbin skull, then compared the data to 95 other hominin skulls. A computer analysis revealed that “Dragon Man” was likely closer on the evolutionary tree to modern humans than to Neanderthals – meaning the species shared a more recent common ancestor with us.

“We found our long-lost sister lineage,” Ni said.

Stringer thinks that Homo longi – along with other hominin fossils previously found in China that had not been assigned a species – is part of a distinct population of human ancestors that thrived in East Asia during the Middle Pleistocene.

Homo longi dragon man
An illustration of Homo longi, or “Dragon Man,” a new human ancestor discovered in China.

However, Ian Tattersall, an anthropologist with the American Museum of Natural History who was not involved in the research, told Insider that he’s unsure Homo longi is really a sister lineage to modern humans. That’s because skulls from Homo sapiens have distinct foreheads, and the bones that make up the face are retracted from the forehead, Tattersall said. He thinks “Dragon Man” is missing that characteristic.

“I’d reserve judgement on the claim of a particularly close relationship with Homo sapiens,” he said.

Tattersall said he doesn’t have a problem with assigning the skull to a new species, though.

‘Dragon Man’ could be a Denisovan

denisovan
A portrait of a juvenile female Denisovan.

It’s possible, Stringer said, that Homo longi is actually a member of the Denisovan population – a human ancestor that lived in Asia from 500,000 to 30,000 years ago. If that were the case, he added, “then we know that they did interbreed with both Neanderthals and our species, and some of the Harbin group’s DNA could still be in some Homo sapiens populations today.”

Homo longi dragon man
An illustration of Homo longi, or “Dragon Man.”

To investigate that possibility, researchers could collect ancient DNA from the skull for further testing.

“But as the extraction process is somewhat destructive, it needs to be considered very carefully for this precious fossil,” Stringer said.

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A human ancestor previously unknown to science lived alongside ancient humans and Neanderthals – and they all interbred

Nesher Ramla Homo
The partial skull and jaw bone of a newly discovered human ancestor named Nesher Ramla homo.

  • Scientists uncovered a new species of human ancestor named the Nesher Ramla homo in a sinkhole.
  • This ancestor lived between 140,000 and 120,000 years ago in Israel and Arabia alongside humans.
  • New research suggests Nesher Ramla homo interbred with humans, as well as our Neanderthal cousins.
  • See more stories on Insider’s business page.

The eastern Mediterranean coast was a crowded place 120,000 years ago.

By that time, Homo sapiens – anatomically modern humans – had migrated out of Africa and settled in modern-day Israel and Arabia. Meanwhile, Neanderthals – our genetic cousins – had started to thrive in Eurasia.

Now, new research reveals that a third human ancestor was hunting and gathering in the same landscape. Two studies published Thursday in the journal Science describe a previously unknown hominin called the Nesher Ramla homo. The group not only shared tools and technology with their neighbors, they also interbred.

“They lived together and interacted with another,” Rachel Sarig, an anthropologist from Tel Aviv University and co-author of the new studies, told Insider.

Nesher Ramla Homo
A virtual reconstruction of the Nesher Ramla lower jaw bone.

Sarig and her colleagues uncovered a partial jaw bone, which they pieced together from 17 fragments like a puzzle, deep in a sinkhole at an Israeli site called Nesher Ramla – hence the ancestor’s name. There were also chunks of skull and a tooth belonging to the same individual.

Notably, the human ancestor had no chin – a feature distinct to Homo sapiens – and a flatter, squatter head. Those features suggest Nesher Ramla was a more ancient species than the region’s other occupants.

“It was some kind of pre-Neanderthal,” Sarig said.

The team had expected the bones to belong to a modern human.

“Homo sapiens were the dominant population in the Levant” between 100,000 and 200,000 years ago, Sarig said. “We were very surprised when we started looking at the fossils, and it was clear right away that Nesher Ramla was not the same.”

A sinkhole in the Judean Hills

Nesher Ramla Homo
The Nesher Ramla sinkhole in Israel, west of Jerusalem.

The discovery was a decade in the making. In 2011, workers were expanding a limestone quarry in the Judean Hills – between Israel’s Mediterranean coast and Jerusalem – when they found a huge sinkhole.

In sediment about 25 feet down, Sarig’s team uncovered animal teeth and bones, flint stone tools, and the Nesher Ramla bones. They suspect the sinkhole was an ancient watering hole, where animals came to drink and our human ancestors gathered to butcher game.

The researchers calculated that the animal teeth and flint were between 120,000 and 140,000 years old, suggesting Nesher Ramla homo lived then, too. But Hila May, a co-author of the new studies, told Insider that it’s possible this prehistoric human started occupying the area up to half a million years ago.

Nesher Ramla Homo
The patch of sediment inside the Nesher Ramla sinkhole where scientists excavated the fossils.

Typically, hominins that lived during the Middle Pleistocene era in Israel, as Nesher Ramla homo did, are classified as part of the species Homo heidelbergensis. These ancestors are characterized by their use of fire to make tools and cook. But the authors of the study chose not to put this new human in that species, since its anatomical features do not align closely.

Still, May said this ancestor had a very similar way of life to Neanderthals and Homo sapiens.

“They were hunter-gatherers living in small groups, hunting animals like rhinos, horses, and deer,” she said, adding that Nesher Ramla were “not very different in their abilities from other groups.”

Interbreeding among human ancestors

Neanderthal
An artist’s conception of a Neanderthal.

The new study suggests that once Neanderthals migrated to Europe about 100,000 years ago, the Nesher Ramla group played a key role in shaping what they looked like and how they lived.

The new discovery might also solve a genetic mystery. Previous research found that some Neanderthals from the Middle Pleistocene era have genes that come from Homo sapiens. But these modern humans didn’t arrive in Europe until about 45,000 years ago – long after the Neanderthals.

nesher ramla
A stone tool found in the Nesher Ramla sinkhole.

So if Nesher Ramla interbred with both Neanderthals and modern humans in the Levant before Neanderthals expanded west, that could explain the migration of the genes.

“We needed some explanation how Homo genes got to Europe before Homo got there,” May said.

And the three hominins did more than just interbreed – evidence from the sinkhole also suggests they shared tool-making technologies, using the same types of flint tools made in the same way.

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Fossils unearthed in China reveal a new species of giant prehistoric rhino – the largest land mammal to ever walk the Earth

giant prehistoric rhinoceros stands as tall as trees against a cloudy sky
An illustration of the Paraceratherium linxiaense giant rhinoceros in the Linxia Basin during the Oligocene.

A batch of newly discovered fossils come from prehistoric giant rhinos – the largest known land mammal in the history of the Earth.

Paleontologists discovered a complete skull from one rhino and three vertebrae from another, in the Linxia basin in the Gansu Province of northwestern China. The set of bones is 26.5 million years old.

Genetic analysis revealed that the fossils belonged to a species of giant rhino that scientists had never seen before. The team of researchers from China and the US dubbed the new animal “Paraceratherium linxiaense.”

“Usually fossils come in pieces, but this one is complete, with a very complete skull and a very complete jaw, which is rare,” Deng Tao, who led the team that discovered the fossils, told CNN. Deng is a professor at the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences.

Taller than a giraffe and roughly the size of six elephants, the rhino towered 23 feet above the ground, and its body was 26 feet long, Deng told CNN. It weighed roughly 24 tons. The skull was more than three feet long.

“It was very rare for a skull of that size to be preserved,” Deng said.

Deng and his colleagues shared their findings in a study published in the journal Communications Biology on Thursday.

A clue to the giant rhinos’ mysterious migrations

Scientists already knew about giant rhinos, or Paraceratherium, which have been found across Asia – mainly in Pakistan, Kazakhstan, Mongolia, and China.

But the new species, Paraceratherium linxiaense, shows that these prehistoric pachyderms made huge migrations across the continent.

In the early Oligocene era, 31 million years ago, giant rhinos moved out of the northern Tibetan plateau.

“Animal migration is linked to climate change. So 31 million years ago, when the Mongolian plateau dried up, they moved south,” Deng told CNN.

The new species, which is descended from those early migrants, indicates that giant rhinos made the trek back north during the late Oligocene. To get to Linxia, they would have had to cross the Tibetan plateau. According to Deng and his colleagues, this means the plateau must have been much lower than it is today.

“The weather got wet and they went back to the north,” Deng said. “Therefore, this discovery is of great significance to the study of the whole plateau-uplift process, climate, and environment.”

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How a 14-year-old picked up a piece of fossil almost 20 years ago and jumpstarted the beginning of dinosaur discovery in Australia

Dr. Scott Hocknull and Robyn Mackenzie pose with a 3D reconstruction and the humerus bone of "Cooper," a new species of dinosaur discovered in Queensland and recognized as the largest ever found in Australia.
Dr. Scott Hocknull and Robyn Mackenzie pose with a 3D reconstruction and the humerus bone of “Cooper,” a new species of dinosaur discovered in Queensland and recognized as the largest ever found in Australia.

  • One of the 15 largest dinosaurs in the world was discovered in Australia.
  • The discovery comes less than 20 years since the country first began finding dinosaur fossils.
  • Australia was believed to not have any before a 14-year-old found a piece in 2004.
  • Visit Insider’s homepage for more stories.

Less than 20 years before “the southern titan” became the largest dinosaur discovered in Australia, a 14-year-old boy picked up a piece of fossil that would begin the hunt for the extinct creatures on the continent.

Robyn Mackenzie, Director of the Eromanga Natural History Museum, which houses the dinosaur, told Insider the discoveries began after her son, Sandy, found an unusual rock on the family property in the outback of Queensland.

“And as it turned out, this was the very … beginning of the discoveries of dinosaurs in a really large part of outback Australia, where previously they’d never been discovered before and it wasn’t even a belief that they would have been preserved in that area because of weather,” Mackenzie said.

Not long after that discovery, a team dug up the skeleton of what would be the Australotitan cooperensis, or “southern titan,” in 2007. It would take another 14 years to officially identify and describe the dinosaur to find it was among the top 15 largest in the world.

Mackenzie told Insider her team is currently describing another dinosaur that could possibly be larger than the super titan.

Australia, unlike China or North America, wasn’t a great home for dinosaurs

Bri Bollmann, host of the NeoJurassic podcast, told Insider that during the dinosaur era a great deal of the landmass that is now Australia was underwater, making it difficult for dinosaurs to live and have their fossils preserved there.

“There wasn’t really a lot of available landmass for dinosaurs to be living on for much of their time on earth,” Bollmann said.

Australotitan_cooperensis
A rendering of the Australotitan cooperensis dinosaur discovered in Australia.

It’s not that dinosaurs didn’t live in Australia, but simply that much of the landmass was underwater and areas that would have been prime real estate for finding fossils have “been brutally eroded down to nothing,” Bollmann said.

“They’re definitely out there, but it’s certainly more of a challenge than say North America or China, for instance, where fossils are just shooting out of the ground left and right,” Bollmann said.

That reality made people very pessimistic at the idea of finding fossils on the continent. Mackenzie said she didn’t believe there were any until American paleontologist Paul Sereno visited Australia in search of fossils in 1998.

Sereno, a professor at the University of Chicago who has discovered several new dinosaur species in countries from Morocco to Argentina, left the continent empty-handed.

“[Sereno and his team] left with the belief that it was possible. There was enough geological evidence to sort of show fossilized evidence, not dinosaurs necessarily, but plants and other kinds of small things,” Mackenzie said.

Mackenzie never imagined that her family would be on this journey

Mackenzie and her family were sheep and cattle graziers. While her husband in particular was fascinated with dinosaurs, they never imagined ever doing any work in paleontology.

“Our family was around all this when [Sereno] came and so obviously got inspired by all that,” she said. “[We] still had no idea what it was going to look like since they didn’t find any dinosaur fossils at that point. We were feeling very confident. We knew it was very possible but we just really didn’t know too much about it.”

But after her son discovered the bone on their property a few years after Sereno left Australia, they realized there could be more and began learning about dinosaurs and digging. Finding one fossil led to finding many, until eventually Mackenzie and her team found the largest in the country.

“It’s such an unexpected thing and I guess not in my wildest dreams would I have ever thought previous to the day that that first piece of bone was found that I would be doing what I’m doing today,” she said. “It’s quite extraordinary when you think back on that fist-size piece of bone that our son found in 2004, which he easily could have just left on the ground and kept going. But he picked it up and that marked a change in the history of our paleontology, a change in the history of the path our family has taken.”

By understanding how and where they lived, we could understand more about how dinosaurs may have gone extinct

Bollmann said the Australian discoveries could give greater insight into how dinosaurs lived and allow us to understand how some of the largest creatures to graze the earth went extinct, which could be a lesson for humans.

He explained that the discovery of these large dinosaurs shows how they grew and developed to adapt to their environment, but ultimately it was that very large growth that helped bring about their extinction.

For humans, he said, we’re developing at such a fast pace, with so many different ecosystems we rely on for our survival that if any were to malfunction, we may also become too big for our own survival.

“What I think is interesting about these dinosaur discoveries and what we’re learning about in Cretaceous species and
Titanosaurus is again a reminder or perhaps a warning to people to realize that we are very much linked with the natural world and we think we’re above it and we think we can navigate these crises better than we actually can,” he said.

He said learning about how and what happened to the dinosaurs through these discoveries can help people learn “where we are in our relationship with the world today. I think that is the strongest value that we can have.”

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One of the biggest fossil finds in California history has revealed ancient elephants, camels, and bone-crushing dogs

Mastodon skull in ground photo by East Bay Municipal Utility District
A fossilized mastodon skull and tusk discovered in an area of California east of Oakland.

  • A ranger patrolling a watershed area east of Oakland, California discovered a trove of hundreds of fossils last summer from nearly a dozen ancient species. The site contains hundreds of petrified trees as well.
  • It’s one of the largest fossil finds in California history, and new fossils are still being unearthed there almost every day.
  • The discovery include fossils from prehistoric elephants with four tusks, mammoth-like mastodons, tortoises, and camels. The findings have so far all been between 5 and 10 million years old.
  • The trove’s precise location remains a secret to protect the fossils and prevent looting.
  • The photos below show some of the findings so far.
  • See more stories on Insider’s business page.
Ranger Greg Francek was patrolling land in northern California last summer when he spotted a weird looking rock. “I was curious and had a closer look,” Francek told Insider.

california fossils
Ranger Greg Francek discovered a petrified tree that’s million of years old in northern California.

 The rock wasn’t a rock at all, but a petrified tree that was millions of years old.

“One end of the tree was partially exposed, and — to my surprise — I could see the tree rings,” Francek said. 

The land Francek was patrolling is east of the San Francisco Bay — he has monitored watershed land for California’s East Bay Municipal Utility District (EBMUD) as a naturalist for more than a decade. Francek knew he’d come across something special, so he called paleontologist Russell Shapiro at California State University, Chico.

It wasn’t the first time Shapiro had been asked to look at potential fossils. “We get that call a lot,” he told Insider. But when Francek took Shapiro to see the ancient tree, they discovered a stunning trove of animal fossils.

california fossils
A photo of a mastodon tooth discovered in an area of California east of Oakland.

“The very first day, I could look on the ground and go, ‘Well, that’s an elephant. That’s a rhinoceros. That’s a tortoise. That’s a camel,'” Shapiro said. “We found all this just by tripping over it.”

Shapiro knew it was an unprecedented discovery: Francek, it turns out, had stumbled across one of the largest fossil finds ever found in California. 

“You kind of look around at the landscape and just think, ‘Oh, my god, there’s gonna be so much stuff here,'” Shapiro said.

EBMUD announced the finding earlier this month.

 

In the 10 months since that first discovery, the duo has helped to unearth several hundred fossil specimens from nearly a dozen species. All are between 5 and 10 million years old.

california fossils
Ancient wildlife that lived during the Miocene epoch, between 23 million and 5.3 million years ago.

Now, a team from EBMUD and CSU, Chico are steadily excavating the site. The fossils they’ve found offer a glimpse into an era of history known as the Miocene epoch, which occurred between 5 and 23.5 million years ago.

California looked quite different during the Miocene — there were no Sierra Nevada mountains, according to Shapiro, and dry grasslands were peppered with volcanoes. Still, the creatures that inhabited the land bore some resemblance to animals alive today. 

Francek has discovered fossils of animals like rhinos, tortoises, and tapirs, which still exist, as well as extinct species like mastodons – shaggy, woolly mammoth-like beasts with tusks.

california fossils
A tapir jawbone discovered in an area of northern California east of Oakland.

Shapiro recalled excavating a particular tapir jaw (pictured above) — he said he thinks tapirs are some of the cutest animals “because they look like a pig, but they have a nose like an elephant.” 

Francek said it’s tough to pick a favorite fossil from the site, especially because he continues to find more whenever he visits.

california fossils
A shell from an ancient tortoise, discovered in an area of California east of Oakland.

“The giant camels are so cool. I like horses. And I like to think about the tortoises walking around the landscape like little armored tanks,” he said.

“I guess the creature that has my imagination working overtime is the gomphothere,” Francek added, “a four-tusked ancestor to the modern elephant.”

california fossils
An artist’s illustration of gomphotheres, early elephants that lived in North America between 12 million and 1.6 million years ago.

Gomphotheres were widespread in North America during the Miocene. They had tusks protruding from above and below their mouths.

Francek has found fossils from numerous gomphotheres, including an enormous, complete lower jaw and tusks.

california fossils
Ranger Greg Francek uncovers a gomphothere fossil.

That jaw, he said, “required 124 hours of excavation with hammer and chisel, and a tractor to lift it out of the ground.”

Shapiro said the team has unearthed countless herbivores but very few predator fossils. Ten months into the excavation, he said, “we’re just starting to find evidence of carnivores.”

Epicyon_haydeni_skeleton_(white_background)
A skeleton of a bone-crushing dog, Epicyon haydeni, in the Los Angeles Natural History Museum.

In addition to fossils of weasel and fox relatives, they found evidence of bone-crushing dogs — prehistoric dog-like creatures that split off from the species that eventually became our pets.

These ancient dogs had strong jaws, Shapiro said: “They evolved the ability to chomp bone.”

He thinks these dogs were the dominant carnivores in the area millions of years ago, before they went extinct at the end of the Miocene. 

The hundreds of fossilized trees found at the site so far can help scientists understand what happened to California’s climate at the end of the Miocene.

Large_Blue_Oak california
A large Blue Oak in a pasture in Mariposa County, California.

During those years, the Earth was starting to get colder, paving way for the first global ice age 2.4 million years ago.

“We can really tell that the temperatures were starting to drop quickly,” Shapiro said. “Right before this period, you find more tropical plants in California and elsewhere. And then right around this time, you’re seeing the spread of oaks and other plants like redwood trees that really prefer a cooler climate.”

Shapiro and Francek think the trove has more to offer. Francek said he’s been back to the site almost every day since last summer looking for new finds.

california fossils
A scientist examines fossilized mastodon tusks found in California.

When he discovers something new, Francek takes photos, documents the location, contacts Shapiro, and starts trying to figure out what the critter might be. Recently, he uncovered a mastodon skull, complete with its tusks, fossilized in a rock.

“Every time he goes out, he finds something new, Shapiro said. “I’m getting used to him texting me photos almost every day.”

Once fully excavated, the fossils get taken to a lab in Chico. Shapiro said the team has finally secured a lab large enough to properly study all the findings. They’re working to count them and date the fossils more precisely.

california fossils
Two scientists chisel away at mastodon tusks discovered in an area of California east of Oakland.

“All of these bones come from pretty much one geologic layer,” Shapiro said.

That suggests the ancient creatures were fossilized around the same time. 

The trove’s precise location remains a secret, however, in order to keep the area safe from vandals and looters.

San_Francisco_Bay_Area_Water_Trail_Vision_Map
A rough outline of the East Bay Municipal Utility District’s area of coverage.

EBMUD maintains a 28,000-acre (44-square-mile) tract of watershed land in northern California that includes cities like Oakland, Richmond, and Hayward. Francek’s findings lies somewhere in this area.

Since excavations are ongoing, EBMUD does not allow the public to visit the site. Instead, it has set up an online tour of the findings for users to explore.

 

 

The secrecy is warranted: After Francek’s initial discovery, Shapiro recalled the ranger’s excitement at the prospect of showing him that first petrified tree. But when they arrived part of it was missing.

california fossils
A mastodon skull fossilized in ancient rock.

“It was like a punch to the gut to find that some of the petrified tree remains had been stolen and vandalized,” Francek said.

After that, the team quickly secured the remaining specimens and installed an around-the-clock patrol of the site.

“We intentionally waited nearly a year to announce the discovery so that we could establish solid security measures,” Francek added.

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T. rexes liked to walk as slowly as humans do – at a leisurely 3 miles per hour, a new study finds

t.rex
The skeleton of a T. rex named Trix at Naturalis Biodiversity Center in the Netherlands.

For all the awe Tyrannosaurus rex inspires, the “king of the dinosaurs” wasn’t very speedy.

Paleontologists already knew this predator was slow: It could only reach a maximum speed between 10 and 25 miles per hour. A 2017 study suggests that if a T. rex went any faster than 12 mph, the predator’s bones would have shattered – so it walked quickly to pursue its prey when needed.

But according to a study published Wednesday, T. rexes didn’t like walking fast if they could help it.

The researchers calculated that the dinosaur’s preferred walking speed was a 3-mph stroll.

That’s just under the average preferred walking speed for a human. So you could probably out-walk a T. rex, or at least keep up with one during its evening jaunt.

“Humans and T. rex would not, if the study is right, have had very different walking speeds,” John Hutchinson, an evolutionary biomechanics expert at the Royal Veterinary College in London who was not involved in the research, told Insider.

T. rexes preferred walking at the same speed that elephants do

myths about dinosaurs jeff goldblum jurassic world dinosaur trex
Jeff Goldblum in front of a model dinosaur to promote “Jurassic World: Fallen Kingdom” in London, England.

An animal’s preferred walking speed enables it to move about using the least amount of energy possible, according to Pasha van Bijlert, the new study’s co-author.

While it may seem like the slower you walk, the less energy you use, that’s not necessarily the case. The best way to achieve maximum energetic efficiency is by finding a locomotion sweet spot known as resonance.

Imagine you’re swinging on a swing, trying to get it moving by swaying your legs back and forth. If you sway too quickly or too slowly, nothing happens. But undulating at just the right rhythm gets your body parts to resonate, and swing most efficiently.

A similar resonance happens when you’re walking at your preferred speed and your body finds a natural step rhythm.

“Many animals have a roughly similar preferred walking speeds: ostriches, elephants, giraffes, horses, gnus, and gazelles are the animals we’ve found data for, and they’re all not that fast when they don’t have to be,” van Bijlert told Insider. These animals prefer to walk between 2.2 and 3.1 mph, just like T. rex – and just like us.

jurassic park t rex
A shot from the 1993 movie “Jurassic Park.”

That means the iconic scene from the 1993 film “Jurassic Park,” in which a T. rex chases a group of park visitors driving away, isn’t very accurate.

“I don’t think anybody believes a T. rex could outrun a Jeep, but it sure does make for a good movie,” van Bijlert said.

T. rex’s tail helped it walk efficiently

Researchers previously calculated T. rex’s walking speed by looking at fossilized footprints, then using the distance between those tracks to estimate the length of the dinosaur’s stride. Those earlier estimates suggested T. rex could walk as fast as 6.7 mph.

But instead of focusing on what T. rex’s legs were doing, van Bijlert’s group looked at the predator’s tail. A T. rex’s tail bobs up and down as it walks.

According to the study authors, every time T. rex’s tail sways up, ligaments inside the tail pull its legs backward, and store energy that then gets released when the tail swings back down. That energy propels the dinosaur forward.

The pace of that tail sway indicates T. rex’s natural step rhythm.

T.rex illustration
A depiction of a full-grown Tyrannosaurus rex.

To figure how fast a T. rex tail would move, van Bijlert’s team created a 3D-model of an adult T. rex skeleton named Trix from the Naturalis Biodiversity Center in the Netherlands. The team reconstructed where all of Trix’s muscles and ligaments would start and end between her tail and legs, and used that model to help calculate her preferred walking speed: 2.9 mph.

Hutchinson said there’s some uncertainty around that result, however, because van Bijlert’s group didn’t take into account whether Trix’s tail would also be swinging side-to-side, and whether the muscles driving that motion might impact her top walking speed.

The new study doesn’t offer further insights into T. rex’s maximum speed, he added.

“There’s a big difference between a casual stroll in no rush versus a sprint,” Hutchinson said.

It would take an adult T. rex more than 13 hours of walking to patrol its territory

T. Rex’s preferred walking speed could tell us how long it took for the dinosaur to forage or scout an area, according to van Bijlert.

A new study from paleontologists the University of California, Berkeley suggested a single adult T. rex lived in an area roughly 40 square miles in size. So if a T. Rex went on a stroll to survey every part of its territory, the endeavor could take more than 13 hours.

t rex
A model of an adult T. rex on display at the American Museum of Natural History in New York City.

T. rex was still a deadly predator, though, when moving at maximum speed.

A fully-grown T. rex was one of the largest carnivorous land animals that ever walked the Earth, standing about 12 to 13 feet tall at the hip and measuring up to 43 feet from tooth to tail. An adult T. rex could weigh between 5.5 and 9 tons – about the size of an adult African elephant.

T. rexes also had a keen sense of smell, acute vision, and excellent hearing, making it hard for prey to avoid detection. On top of that, their jaws had a bite force of 7,800 pounds, equivalent to the crushing weight of about three Mini Cooper cars. No other known animal could bite with such force.

“All evidence suggests it would have no issues capturing similar-sized prey,” Hutchinson said.

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A whopping 2.5 billion fully grown T. rexes walked the Earth in the course of the species’ existence, paleontologists found

Jurassic Park T Rex
A T. rex depicted in the 1993 film “Jurassic Park.”

An adult Tyrannosaurus rex required a lot of space – and the prey therein – to survive.

According to new calculations from paleontologists the University of California, Berkeley, each adult T. rex lived in an area roughly 40 square miles in size.

The study, published Thursday in the journal Science, uses that math to offer an estimate of the total number of these predators that walked the Earth during the Cretaceous Period, between 66 and 68 million years ago: an impressive 2.5 billion.

“The total number did catch me off guard,” Charles Marshall, a paleontologist at Berkeley who co-authored the study, told Insider.

Marshall’s analysis suggests that the entire island of Manhattan or city of San Francisco would be the territory of a single T. rex.

He said he’d been wondering for years how unusual it really is to find a T. rex fossil: “When I hold a fossil in my hand, I always said to myself, ‘I know this is freakishly rare.’ But just how rare is it – one in a million or one in a trillion?”

Comparing the T. rex to the Komodo dragon

The T. rex was one of the largest carnivorous land animals that ever walked the Earth. (That accolade currently goes to the polar bear.) An adult Tyrannosaurus rex could weigh at least 5 tons. It stood about 12 to 13 feet tall at the hip and was about 40 to 43 feet long.

The larger predators are, the fewer of them can live in the same area, since there just isn’t enough food to sustain their massive size. This is known as Durham’s Law. So if researchers know how many calories a meat-eater needs to survive, they can calculate the number of predators per square mile.

While there’s no living predator that resembles the T. rex in size, Marshall compared the dinosaur’s energy needs to those of a Komodo dragon, the largest lizard on Earth.

Komodo Dragon
A Komodo dragon in Indonesia’s Komodo National Park.

Using that benchmark, he calculated that there could have been roughly 3,800 T. rex in an area the size of California at any given time – or just two in an area the size of Washington, DC.

There were about 20,000 adult T. rexes living at one time

Marshall’s team also needed to calculate three other variables to determine the total number of rexes that ever walked the planet: the total land area of suitable T. rex habitat, the dino’s average life span as an adult, and how long these predators existed on Earth.

T.rex illustration
A full-grown Tyrannosaurus rex weighed about 6 to 9 tons, stood about 12 to 13 feet high at the hip, and measured about 40 to 43 feet long.

By reviewing the locations of every T. rex fossil ever found, the study authors determined that the predator lived in about 888,000 square miles of North America – and nowhere else on Earth. Although the animal might have been able to survive in the area that’s now Siberia, Marshall said, he’d be surprised if any rex fossils were ever found outside the one continent.

Using that assumption about the T. rex’s geographic range, Marshall calculated that there could have been about 20,000 adult T. rexes alive at any given time in the species’ existence.

Figuring out how long the T. rex species was around was a bit easier – the oldest rex fossil ever found suggests the dinosaur walked the Earth for the last 2.5 million years of the Cretaceous Period, starting 68 million years ago. Then it went extinct after the Chicxulub space rock struck.

Finally, Marshall’s team calculated how long one generation of adult rexes lasted by looking at the average time span between when rexes became fully grown – at around age 15 – and when they died in their early 30s.

woodward4HR
An artist’s depiction of a juvenile Tyrannosaurus rex.

That means that in the 2.5 million years these animals were on Earth, there were about 127,000 generations of them. Multiply that number by 20,000, and you wind up with 2.5 billion T. rexes.

However, Marshall pointed out that this number doesn’t include baby or juvenile T. rexes. Those were excluded from the calculations because research suggests juvenile rexes were smaller and faster than their adult counterparts, so hunted different prey.

T Rex in New York City
A Tyrannosaurus rex skeleton, named STAN, displayed by Christie’s Auction House in New York City, September 15, 2020.

Marshall’s team’s estimate suggests that the remains of just one in every 80 million adult T. rexes have been found. Currently, there are about 32 well-preserved, adult T. rex skeletons in public museums worldwide, Marshall said.

That means we’ve only dug up 0.00000125% of all the adult T. rexes that ever lived.

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