La Brea’s tar pits are full of mysteries. Here are three of the most confusing

Last year, we began inviting readers to send us their pressing questions in Los Angeles and California.

Every few weeks, we put the questions up for a vote, asking readers to decide which question they’d like to see answered in story form.

This question, posed by Ricky Fulton, was included in one of our recent reader surveys: What are La Brea Tar Pits? Is it a bubbling pile of tar with dinosaur bones sticking out?

You can vote in our next reader questions poll here. Find previous stories written as part of this project here.

There’s more than meets the eye – and the nose – at La Brea Tar Pits.

For those unaware, the La Brea Tar Pits is an internationally recognized Geological Heritage Site located in the middle of Los Angeles. The site is known for its many fossil quarries (called “pits”), where animals, plants and insects have become stuck and preserved in asphalt over the past 50,000 years.

For scientists, it is an invaluable and unique treasure trove of information that allows us to better understand what ancient life was like in today’s Los Angeles.

“The kind of science you can do at La Brea Tar Pits is something you can’t really do at any other paleontological site in the world, just because we have so many fossils and they’re so well preserved” , said Emily Lindsey, associate curator and director of the dig site.

In the fragrant mud – a curiosity for locals, tourists and school children on excursions – more than 3.5 million fossils have been discovered.

To answer Fulton’s question right off the bat, here’s one thing they didn’t find in the pits: dinosaurs.

That’s right – this is an Ice Age fossil site, and experts haven’t found any remnants of T. rextriceratops or other non-avian dinosaurs.

While La Brea’s Tar Pits lack dinosaur fossils, they abound with fossils of legendary Ice Age animals. The two most common large mammals? Dire wolfs (shout out to all “Game of Thrones” fans) and saber-toothed cats.

Despite scientists’ groundbreaking discoveries, mysteries continue to swirl in the seeping pits.

Sometimes, says Lindsey, the things that scientists don’t find in the tar pits fascinate as much as the bones and other objects they discover.

Lindsey described the puzzles posed by the tar pits that remain to be solved.

Here are three of the most enticing:

Why are the remains of some native species – like cougars – largely absent from tar pits?

Something odd: Scientists have found relatively few mountain lion remains in the tar pits.

P-22’s Hollywood Celebrity Status Plus, it might seem odd to worry about the lack of cougar fossils when tar pits have revealed the remains of extinct mammoths, giant wolves, and giant ground sloths.

Still, it’s odd that cougars – which existed in the Los Angeles area during the Ice Age – make up such a small percentage of scientists’ discoveries in the tar pits. The Tar Pits have remains of at least seven different cougars, while its saber-toothed cats number 2,500 to 3,000.

And it’s not just cougars that are missing from the tar pits.

“We have very few mountain lions, very few deer…and only one raccoon,” she said. Aside from coyotes, scientists have found “very few of these [large mammal] ‘ice age survivors’, which is an interesting thing.

Why might cougars be absent from tar pits?

The answer could help scientists paint a more detailed picture of life in prehistoric Los Angeles.

Lindsey and her colleagues have some ideas. Among other potential explanations, it’s possible that – true to their name – cougars always preferred to be in the highlands, and not in the flatter areas of present-day Los Angeles near the tar pits.

Or maybe cougars were afraid to hunt in the same areas as sabertooth cats. “A puma looks like a domestic cat next to a saber-toothed cat – [it’s possible] they wanted to stay away and not be around all that big scary stuff.

Where is the proof of human life?

Mountain lions, raccoons and deer aren’t the only mammals missing from the tar pits. There is also a distinct lack of human remains.

“The humans were there, but why do we find no evidence of it in the pits of La Brea Tar? asked Lindsey. “We have a human skeleton, then we have artifacts that are probably all from the Holocene (our current geological time), but we have no evidence of humans overlapping or interacting with megafauna” via hunting.

That’s puzzling, because “many — maybe even most — scientists believe the primary cause of megafauna extinctions was human activity,” Lindsey says.

Similar to mountain lions, Lindsey notes that the absence of ancient humans could indicate their reluctance to hunt saber-toothed cats and other dangerous animals nearby.

“Maybe it’s because the culture that was here was adapted to the coast and didn’t have to brave, say, a pack of wolves to go and hunt a horse or a camel,” she said. declared. “They might stay close to the shore and collect seashells.”

Why did large mammals start to disappear – and what does this tell us about our future?

Once upon a time there were giant mammals that roamed large tracts of land.

“There were giant wombats in Australia, there were giant lemurs in Madagascar, there were sloths and giant armadillos in South America,” Lindsey said.

So, asks Lindsey, why don’t we have saber-toothed cats, mammoths and giant ground sloths roaming around Wilshire Boulevard today?

A radical change has occurred. “At the end of the ice age, something happened, and it wiped out the top of the body size distribution everywhere but Africa,” she said. “This is the biggest extinction since the extinction of the dinosaurs 66 million years ago.”

Even more frightening, the loss of the giant mammals is being recognized as “the first impetus for the biodiversity crisis we find ourselves in today”, she said.

Why did this extinction event happen? “Most scientists believe that humans must have played a fairly large role in this extinction. But the other thing that was happening was we were coming out of the Ice Age – the last major episode of global warming,” she said.

“Understanding the type of interaction between climate change and human activities, how it affects ecosystems, and how these two processes can intersect to cause extinctions is extremely important.”

The La Brea Tar Pits are positioned to help solve the mystery of the precise death of giant mammals, due to the size and scope of its findings, which can be radiocarbon dated and associated with known changes occurring are produced simultaneously with humans and the climate. .

On the other side of the coin, 90% of the species found in tar pits have not disappeared. “We have tons of rabbits, rodents, lizards, insects and songbirds on our record that still live in the LA area today,” Lindsey said via email.

“We are a survival and resilience record,” she said, which raises some questions. “What made the cougars successful? What made the coyotes successful? What made the oak trees successful?

As the climate crisis worsens today, the answers to these mysteries could pave the way for the future.

“The next decades to centuries are going to be marked by some really extreme global changes,” Lindsey said. “How can we use this information to help life succeed?”

This existential question should give you something to ponder the next time you pass the iconic (and heartbreaking) mammoth statues of the Tar Pits on Wilshire Boulevard.

This story was written directly in response to a reader’s question about the La Brea Tar Pits. Have a question about living in Los Angeles or California? Ask us!