Helen FieldsScience Writer

I’ve been hearing about the La Brea tar pits forever, so I was pretty darn excited when a friend suggested we go see them while I was in Los Angeles. The tar pits were – are – naturally-occurring tar seeps in the middle of downtown Los Angeles. Animals would wander up, see the tasty water, walk in to take a drink, get sucked in by the tar, and die. Which means there’s a truly incredible number of bones down there. And a museum to show them: the Page Museum.

First of all, let’s get straight what kind of animals we’re seeing:

Definitely no dinosaurs. You got that? No. Dinosaurs. They must get this question a lot – the sign is right at the desk where you buy the tickets. The dinosaurs went extinct 65 million years ago, but Los Angeles was under water until about 100,000 years ago. Animals fell into the tar pits pretty recently, when there were already people in the area. (Ok, I think people turned up sometime during the period they refer to – between 40,000 and 11,000 years ago.)

So, this museum is mostly about prehistoric mammals, like American lions and short-faced bears and dwarf pronghorns, all of which used to roam Los Angeles. Most of what the museum has is bones, which, if you like bones, is awesome. My friend and I spent most of the time wandering around talking about evolution (she did her PhD thesis on it, it still confuses me) and talking about comparative anatomy (quite easy to do when you have so many bones to look at).

For example, we talked a lot about elbows and knees:

This is the front part of a California sabertooth. They don’t call them sabertooth tigers anymore, because they aren’t particularly closely related to tigers.

In mammals, anyway, elbows and knees all seemed to bend the same way – elbows point backward when they bend, knees point forward when they bend. These are elbows, at the bottom left. They bend like ours. But mammals vary a lot in where they put these joints.

Cats and dogs keep elbows where we do – in the middle of the leg. Arm. Whatever. But horses keep them way up by the shoulder:

Sorry, there are a lot of bones in that picture. The horse leg is in the foreground. It’s standing on its toes, or fingers; its heel – or the heel of its hand – is about halfway up the leg; and the elbow is up by its ribcage, just below the shoulder

This may not seem particularly earth-shattering, but it kept us entertained the whole time at the museum, figuring out which bones on different animals corresponded.

There were lots of mammoths in the museum, including this 12-foot-tall Columbian Mammoth, the most common mammoth in North America at that time:

So, I asked, why did all these go extinct? Humans killed them, right? My friend (who prefers to be anonymous on the internet, sorry to be all cloak-and-dagger) said, actually, nobody knows. There was climate change, and it looks like there was an asteroid impact and giant forest fires, and maybe human hunters helped, too. But nobody knows for sure.

The museum is arranged around a lovely green atrium, with this lovely great blue heron:

Ok, that’s a fake great blue heron. A sign explained that they’re trying to discourage a real great blue heron from using the pond as his cafeteria (see the orange koi?), so the decoy is there to make him think somebody’s already claimed it. And if you do see a real one, you’re supposed to tell the staff so they can shoo him off.

And if you go outside, the tar pits are still there, burbling away in the park that contains the Page Museum and the L.A. County Museum of Art.

They really do burble – little bubbles of methane gas come up to the surface and pop. Note that they are fenced off, so you don’t turn into a fossil yourself. And excavations are still going on – in 2006, the art museum started digging to build an underground garage and came across 16 new areas of fossil deposits. They brought up 23 big crates of asphalt (absolutely stuffed with bones), which are now being excavated in the park.

UPDATE, later: I forgot to say, the tar pits smell like tar! Ok, maybe that’s not surprising, but it’s cool.

For all my Museum Tourist posts, click here.

Every year during the AAAS meeting, there’s an evening reception where some big science journalism awards are presented. This year, the reception was Friday night at the San Diego Natural History Museum in Balboa Park.

I caught the first shuttle bus to the museum. When they opened the doors and let in the flood of science writers, a guy was standing near the entrance telling us there was food on the second floor. I thought, this guy knows what he’s talking about, and asked him what exhibit I must not miss. He told me to go see the fossils on the second floor. Fossils and food? Clearly that’s where I needed to be.

First: I was impressed that all the signs are in both English and Spanish.

Way to reach out to your population, San Diego. I am delighted to report that the Spanish for “Extinct giant sea cow” is “Vaca marina gigante extinta.”

All the fossils in the museum’s fossil exhibit are local. So as you go through the exhibit, it goes back in time, telling you what San Diego was like in that era and what kinds of critters walked or swam here. This is a walrus from the Pliocene, when San Diego was under water.

It’s head-down, sucking up clams like it would in real life. (The label says modern Arctic walruses feed this way, too.)

The fossil section continued backward, to a section on San Diego’s Eocene rainforest, with funky-looking mammals in the trees. All along, there were cool interactive things – and physical things to do, not just computer screens to poke at. This one lets you sift sand for tiny fossils:

You tilt the sifter thingy back and forth and back and forth until the sediment all runs through the grate and some fragments of bone appear.

Nerd moment: I saw this and said, “Ohmygod, K-T boundary.” The rock above the pale stripe in the middle is Tertiary (T) and the rock below it is Cretaceous (K – from the German “Kreide” for chalk). That pale stripe is the remnants of the event that killed the dinosaurs.

So, below the line, dinosaurs; above the line, no dinosaurs, and a lot more mammals. There’s also lots of neat stuff in the K-T boundary that point toward an asteroid impact as the thing that killed the dinosaurs, like a high concentration of iridium, an element that is a lot more common in asteroids and comets than it is on Earth.

I sat down to eat some tasty, tasty dinner with two strangers who turned out to be highly entertaining. After a while, someone else came and sat with us – and I realized he was the guy who’d told me to go look at the fossils. He turns out to be the museum’s executive director, a job he’s had for 18 years. One of our first questions was why the pendulum wasn’t going. “It should be,” he said.

(It turns out you actually start it by standing outside with a long stick, but this is more fun.)

He also showed off this totally cool globe-shaped screen thing – you can choose from a bunch of different programs, like a plate tectonics one, and it shows you how the planet changed over time. I think in this picture, it’s showing how glaciers advanced and receded during the last ice age (and, correspondingly, how sea levels changed all over the world).

He was clearly proud of his museum’s cool exhibits.

For all my Museum Tourist posts, click here.

Today I went on a reporting trip to chat with a scientist who likes to collect fossils. (I’ll tell you more when the story comes out.) I saw tons of shark teeth, bits of seals and whales, some coral and barnacles, and also…other stuff from the beach.

Spiderman. Heh.

The Science Channel posted more quizzes!

1. Bones. I put in a Harry Potter question. Oh yes I did.

2. Wind Energy. It’s free, it’s windy, it’s wind energy. Includes a question based on a book I was supposed to read in eighth grade. I was a really good kid, but I don’t think I ever finished this book.

3. Fossil Fuels. Do you know why they’re called that? Eh? Do you? Take the quiz!

To see all my quizzes, click here.

This weekend I was in Lawrence, Kansas, where my dad grew up, and stopped by the University of Kansas Natural History Museum. It’s in a great old building atop a hill on the KU campus.

In olden times (the Cretaceous, if you want to get technical – late in the dinosaur times), Kansas was underwater. The west coast and the eastern U.S. were separated by the Western Interior Sea. I love that it has a name, even if it isn’t a very poetic name – like it’s got a name waiting for it, in case the Rockies decide to go back down.

All that water means Kansas is rich in fossils of wacky sea creatures like this guy:

He’s a Xiphactinus molossus, a kind of bony fish. Doesn’t he look mean?

Also awesome: crinoids.

Crinoids are echinoderms, relatives of starfish and sea urchins that leave behind a lot of hard bits. They make beautiful fossils (a couple of these have been colored to show you what you’re looking at.) There are actually still crinoids, but they’re not nearly as diverse as they used to be.

One of the prized possessions of the museum is Comanche the horse. Dead horse! In a glass case!

Comanche survived the Battle of Little Bighorn in 1876, with several arrow and bullet wounds. After he recovered, he became a mascot for the Seventh Cavalry. He did parades and wandered around Fort Riley, about 100 miles west of Lawrence. When he died in 1891, he was sent off to the University of Kansas to be preserved. In 1893 he – or his skin, anyway – helped represent Kansas at the Chicago World’s Fair.

Here’s a great slide show on his restoration a few years ago. They had to build a full-size model to make sure he’d make the corners on the way to his new exhibit space. I love the pictures of him wrapped in plastic for the move. His head’s sticking out, which is reassuring – you wouldn’t want the dead horse to suffocate.

My dad remembered going to the museum on Cub Scout outings to see the snakes. I checked and, yep, they’ve still got snakes. (Probably not the same snakes as in 1950. No word if Cub Scouts still come look at them, but I can’t imagine they’d miss the chance.) They have fifteen species that are found in Kansas, each in its own cheerfully painted case.

I feel like the common garter snake, at right, got the nicest room. All those cheerful Kansas sunflowers.

The cottonmouth seemed particularly mean.

For one thing, it’s got the triangular head that screams, “I AM VENOMOUS.” Also, there were little furry gray things floating in the water that looked a heck of a lot like bits of mouse. I thought snakes swallowed their food whole, but I don’t know, maybe that one put up a fight.

For all my Museum Tourist posts, click here.

photos: me, of course

Tonight I went on a tour of the fossil labs at the Smithsonian’s National Museum of Natural History, organized by the DC Science Writer’s Association. I learned many exciting things and took pictures with my cell phone camera, ’cause that’s all I had. Sorry.

Sample fun fact: When they find little fossils in the field, they wrap them up in toilet paper and tape.

I like the one that says “Chunk-o-Bone.” And the other one that says “Bone?” Might be a bone. Might not. We also learned that you can sometimes tell the difference between bone and petrified plant material by licking it – bone is porous, so it wicks liquid away from your tongue and your tongue sticks to it. Petrified wood is solid and doesn’t do that. (Unfortunately, I didn’t get a picture of this demonstration.)

We learned a lot about preparing fossils. When fossils come back from the field, they’re often stuck in rock. So, you want to cut away the rock. The preparators have jackhammers as small as a dentist’s drill. Some rock is just too hard for chipping away, though. These vats are for dissolving fossils in acid:

These fossils are in limestone, which apparently is really hard. If you chipped bits of it away, it would take forever. So instead they bathe them in really weak acetic acid, over and over and over and over. After every overnight bath, someone has to coat the bones with a plastic solution so the acid won’t dissolve them, too. With weekly baths, dissolving the bones out of a rock takes…forever. Like a year. Acid won’t dissolve plant fossils, so if that’s what you’re trying to get out of the rock, you can just throw in the rocks, put mesh over the drain, add some super-strong acid, and wait.

The vertebrate paleontology folks are in the process of making custom-fit foam and plaster jackets for all their fossils. Big fossils are heavy. REALLY heavy. They’re basically rocks, and think how big a dinosaur leg bone is – that’s a big rock. Until someone dug them up, these fossils were happily ensconced in some kind of rock formation. So if you have a big old bone sitting on a shelf, and it’s just resting on three or so points, it’s really likely to break. Here’s a fossil getting its cast made:

The sand supports the weight of the fossil while it’s being worked on. My favorite fact: That sand is made of crushed garnets. It’s cleaner than regular sand, apparently. Also, red. And so pretty!

Our last stop was in a big room with big stuff. Example: That white thing in the back is a fossil branch of some kind of ancient tree fern. It’s so big, for years it leaned against the wall outside in the parking lot. They were afraid it would break the floor if they brought it inside. Note that it is inside now. They cut a lot of rock off the back before they brought it in.

At left is some dinosaur whose name I’ve forgotten. This is actually a cast; the original has been on display, but they’re trying to take their type specimens down. (I think he said there are seven in the dinosaur hall right now.) A type specimen is the specimen that defines a species, so paleontologists want to be able to study them. The museum is replacing them with casts so scientists can work with the type specimens.

The Natural History has redone two of its major halls recently – mammals and oceans – and a third is opening this spring. The dinosaur hall is next on the list. Apparently a lot of the skeletons are mounted based on antiquated ideas about how dinosaurs stood. Some date to shortly after the museum opened – which was in 1910. So if you know anyone with a few million dollars to throw around, the Smithsonian would love to hear from them.

UPDATE, 2/1/10: Here’s some more info about that giant tree fossil. It was a “scale tree” and it came from a coal mine in Iowa. The museum received it in 2005.

For all my Museum Tourist posts, click here.

photos: me.

Today I wrote an extremely teensy story for ScienceNOW. It’s at the bottom of this list. It’s about a 300-million-year-old fossil brain. That’s really old. Soft tissue doesn’t usually get preserved, but they found this one with the crazy bright x-rays of a synchrotron.

Those little teeny stories only run with one picture, so I’m really just blogging here to share this drawing of what the iniopterygian (it’s a cartilaginous fish, related to sharks and stuff) might have looked like:

Is it just me, or does this fish look…well…kind of dumb? In a wide-eyed, hopeful way. Sorry bout the extinction, little guy.

Image courtesy of PNAS

I’m writing a whole batch o’ quizzes for the Science Channel (it’s part of the Discovery empire, which is based just up the road in Silver Spring). Three more went up today! You can test your knowledge on:

Dinosaurs! This one is probably the funniest. And the one with the most questions about Jurassic Park.

Taste! I quoted a They Might Be Giants song in this quiz. An obscure They Might Be Giants song.

Bugs! A month or so ago I heard a talk about insect diversity. The guy said, “To a nearest approximation, all species on earth are insects.” I didn’t get to use that quote in the quiz, so I’m happy to be using it now. Bugs are awesome.

Hey, lookit – I wrote this. Things I know now that I did not know 38 hours ago:

1. Pterosaurs were not dinosaurs. They were reptiles like dinosaurs, and they lived with the dinosaurs and went extinct with the dinosaurs, but they weren’t dinosaurs – they were pterosaurs.

2. I knew about birds having hollow bones, but it turns out they also have sacs filled with air that hang around outside the bones. Weird! Birds have a really nifty respiratory system, which, when I looked it up in my freshman biology textbook, did seem vaguely familiar – those air sacs help move a ton of air through the lungs so they can keep pumping enough oxygen to keep the muscles going during flight. Flight takes a LOT of muscle action. You try flapping your arms for an hour and see how you feel.

3. How to spell Rhamphorhynchus (a genus of pterosaur). Actually, apparently I did know this, because the guy said it, and I typed what it sounded like, and I’d guessed correctly. What can I say? I’m a born speller.

art credit: Mark Witton, 2009

I blogged again! This one is about using synchrotrons to look at ancient things. A synchrotron is a really bright x-ray machine the size of a football field. If you point it at a bug in amber or an ancient scroll, it’s like x-raying the sample, except way stronger. (I mean, you are x-raying it. Your x-rays are just super bright.)

I went to the synchrotron press conference this morning expecting it to be mildly interesting and found out that, wow, they can do crazy stuff with these really bright x-rays. One guy had all these bug models that combined *two* crazy pieces of technology: the synchrotron, which zapped amber and made 3-d images, and a 3-D printer that turned the computer version into a plastic model that you can hold and scare people with. (The real bugs are teeny; the models are the size of your hand and off-white.)

Another person talked about a new project that’s just starting, on figuring out how to read scrolls without unrolling them. Turns out the x-ray technology isn’t the problem – it’s the insane quantities of computer power you need to put the image together.

Anyway, totally cool. Read all about it! (Oh, and for more about the Archimedes Palimpsest, that project has a great website.)