How Can These Flies Live in Oily Black Tar Pits? | Deep Look

In the sticky oil seeps known as the La Brea Tar Pits, the tiny petroleum fly and their larvae thrive in the natural asphalt that oozes up to the surface. The larvae hunt among the fossilized bones of dire wolves, mammoths and saber-toothed cats.

DEEP LOOK is an ultra-HD (4K) short video series created by KQED in San Francisco and presented by PBS Digital Studios. See the unseen at the very edge of our visible world. Explore big scientific mysteries by going incredibly small.

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But among these fossils, the tiny petroleum fly and their larvae not only survive but thrive in the natural asphalt that still oozes to the surface today.

While scientists aren’t entirely sure how, adult petroleum flies can walk and mate on the tar pits without getting their feet stuck. But if any other part of their body touches the asphalt, they’re doomed.

Their larvae, on the other hand, truly love this environment. They can fully submerge in the dark, viscous asphalt and feast on small insects that get trapped in it. As they eat, petroleum fly larvae end up ingesting a lot of asphalt, which you can see through their guts. Humans, however, could get cancer if we ingested that much asphalt.

The larvae need the asphalt to survive. While other insects rely on a waxy layer to protect them from the elements, the petroleum fly larvae’s exterior is so thin that it would dry out without the asphalt.
Living among the fossils, the petroleum fly, with unique adaptations and resilience, continues to be a mystery to scientists.

--- Are scientists still excavating the La Brea Tar Pits?

Yes. Scientists are working on two active excavation sites where they are still finding fossils of different plants and animals that have lived in the LA Basin between 50,000 years ago and today.

--- Are there dinosaurs in the La Brea Tar Pits?

A common misconception about the La Brea Tar pits is that they contain dinosaur bones. Dinosaurs went extinct about 65 million years before the tar pits began to form. The tar pits are an ice age fossil site that formed between 50,000 and 40,000 years ago.

--- Have they ever found human remains in the La Brea Tar Pits?

Yes. The partial skeleton of a human woman was discovered in 1914.

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#petroleumfly #oilfly #TarPits

[NewMessage]

Look.. finding an affordable place in LA means making a few concessions, y'know?

[yumibro]

I grew up going to the La Brea tar pits. Went to the museum, saw the fossils, did the little demonstration where you try to lift a weight out of various tar containers with a handle. I was always told nothing could survive in it. Now, like 15 years later, you're telling me there are bugs that have WHOLE LIFECYCLES in the pits?? Science is amazing. Life really does find a way.

[jimmytaco]

So basically if the tar is almost a road then the maggots are really just eating roadkill like normal ones

[scottb]

This has to be one of my favorite episodes. The stunning visual contrast between the translucent larvae and the jet black asphalt combined with the peculiar biology is just awesome. Hats off to the film crew here, and to whoever decided to dedicate an episode to these incredible creatures.

[nondisclosureable]

This answers the question I've had since childhood about why we get fossil bones from the pits instead of anaerobic mummies.

[alden]

It's kind of easy to see how such adaptations could arise. Any time an animal dies in the pit, maggots would inevitably consume the carcass. The carcass would sink, and most of the millions of maggots would die under the tar. Eventually, a few would manage to survive, and whatever mutated genes made that possible would be passed on. It's a strong selective pressure to survive certain conditions, and with the sheer number of "chances" each brood has to gamble on having even one surviving to escape a sinking carcass, odds are in favor of a new trait arsing in the population.

[Langolyer]

"They can even be eaten by its own larvae"
Sounds like a recurring trope.

[mypal]

That fly can get out of a sticky situation.

[ameliawright]

I've always found the Petroleum Fly fascinating- so glad to see a video on this weirdo.

[GandalfTheTsaagan]

I love life's ability to rurn anything into an ecosystem

[MommaOhana]

This just proves for every pot there is a lid somewhere. Who would’ve thought something, anything, could live inside the pits?!

[DreamDaddie]

Woo! Something to watch before work. Thank you, Deep Look!

[mrfish.-]

When I first saw these guys, I just assumed they somehow fed on the ancient bones in the tar! Another amazing vid as always DeepLook team!

[a.m.v.]

I’m 64 and I’ve been to LA many times, last year I finally stopped at this place and I loved it. Fascinating place.

[liveinamber]

Fascinating! Never would I have though there would be an animal specifically adapted to life in asphalt pits! What a delight to learn about such a well designed creature!

[jimb.]

*"This maggot is it's baby!"*

*ME:*

[jacksim]

absolutely perfect alien worm design right here on earth

[alden]

4:11 Aw, I think I'll name them Al And Peg...

[alexforce]

Insect in a tar pit: " - Well, just great, this day can't get any worse" ( Wild fly larvae appears behind them)
insect: "- Why Im hearing boss music?"

[RumBrave]

So this is why there are always so many flies at the tar pits! Next time, I'll have to look for the larvae gliding across the top. Amazing how easily they get around and talk about a specialized organism!
Visiting the tar pits is always super interesting. The main pits are fenced off for obvious reasons but you can find small trickles of tar that seep up from the ground around the area and play with it if you're so inclined. The museum itself has an interactive exhibit where you can feel how much force it takes to pull out of the tar and how exhausting it would be. Also, if you've only ever heard of dire wolves from game of thrones, you might be surprised to find out that they were a bit smaller than today's wolves, but they did have a stronger jaw. The museum has an entire wall of their skulls.