The Past, Locked In Amber

Scientists excavating an Indian amber deposit say it dates back more than 50 million years, and contains the remains of at least 100 previously undocumented species of insects. American Museum of Natural History curator David Grimaldi describes the amber, and the organisms trapped within it.

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JOE PALCA, host:

Up next, amber. Wondering what life was like in India 50 million years ago? Researchers say a vast amber deposit in Western India could help answer that question.

The amber contains at least 100 species of insects, including bees, termites and ants frozen in time, as well as fungi, flora and crustaceans. The creatures were stopped in their tracks in the sticky plant resin millions of years ago. Thanks to the amber, scientists can see what was walking around or hanging around in this part of the world millions of years ago, and that gives them some idea of what the landscape looked like.

Joining me to talk more about this window into prehistoric India is my guest, David Grimaldi. He's curator in the Division of Invertebrate Zoology at the American Museum of Natural History here in New York, and he's in our New York studio. Thanks for coming in, Dr. Grimaldi.

Dr. DAVID GRIMALDI (Curator, Division of Invertebrate Zoology, American Museum of Natural History): My pleasure to be here.

PALCA: So I guess, you know, tell us about these amber deposits. How did you stumble on to them?

Dr. GRIMALDI: Well, I have...

PALCA: Stumbled, maybe not. Maybe you were more careful.

(Soundbite of laughter)

Dr. GRIMALDI: No, we knew they were there. We have colleagues in India who originally discovered these deposits. They occur in huge, open-pit mines that are used to mine lignite, which is like a semi-fossilized coal. And they had discovered that amber occurred there. However, when my team joined their team and a German team from the University of Bonn, all got together, we started collecting the amber in huge amounts and screening through it and finding a tremendous wealth of insects and other life.

PALCA: Well, you brought in a couple of examples. And I have to say that this amber doesn't look like the picture of amber I have in my mind.

Dr. GRIMALDI: That's right. It's not a real commercially viable type of amber. It's pretty dirty, and in fact, it's actually kind of sticky on the inside, whereas, like, Baltic amber or Dominican amber is beautiful, smooth, lustrous. And it reflects a chemical difference.

PALCA: So how do you get the things inside out to study them?

Dr. GRIMALDI: Well, this amber from Western India is actually very distinctive. You can actually dissolve this amber, and you can extract the insects and other things entirely from them, whereas the other kinds of amber, like Baltic amber or Dominican amber, you can't do that. It's not soluble.

PALCA: Wow.

Dr. GRIMALDI: But what we actually do is we do it the hard way and the old-fashioned way. We actually trim through the piece of amber, looking to see who's home, and polish and grind it and just look for the little insects.

PALCA: What's I mean, are these species that you're finding never seen before, or you're still characterizing them?

Dr. GRIMALDI: Everything's new. I mean, this is a very distinctively unique deposit from this area of the world, although the species we're finding have relatives from Northern Europe in Baltic amber, from Australia and parts of South and Central America.

PALCA: Okay. Well, we're talking with Dr. David Grimaldi from the American Museum of Natural History about these massive amber deposits that were found in India and the interesting creatures captured therein.

So stay with us. We're going to have to take a short break, and we'll be back.

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PALCA: This is SCIENCE FRIDAY from NPR.

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PALCA: From NPR, this is SCIENCE FRIDAY. I'm Joe Palca. We're talking about amber with my guest, David Grimaldi. He's a curator in the Division of Invertebrate Zoology at the American Museum of Natural History in New York.

And if you have questions for Dr. Grimaldi, give us a call, 800-989-8255. That's 800-989-TALK. And this is - these are these massive deposits of amber that were found in mines in India, and they are now in the process of going through them to see what's interesting inside.

And apparently, they're all new species. What can you learn from that? I mean, these are new species.

Dr. GRIMALDI: Well, we can actually see transitional forms between living and other extinct things. So fossils actually are important for evolutionary research. It tells us a lot about the origins of the Asian fauna.

And this particular deposit, I find probably the most interesting aspect of it is that the resin, the amber, was actually formed from a type of tree called dipterocarps. And today, these types of trees are the dominant tree in Southeast Asia. They really form tropical forest. They are the 80 percent of the trees in a tropical forest in Southeast Asia can be dipterocarps.

And there had been some controversy about the age of tropical forests. And this is a unique discovery in terms of helping to date the age of tropical forests.

PALCA: So set the scene a little bit for us. Fifty million years ago, what did this part of India look like? I mean, if you've got big trees and something that grows only in tropical forests, presumably you've got a tropical forest.

Dr. GRIMALDI: That's exactly it. The point being that tropical forests are very ancient ecosystems.

PALCA: And what else was there? I mean, you've got all these creatures. I'm presuming the larger animals weren't trapped. But what would this place have looked like?

Dr. GRIMALDI: It would look actually if you looked up close, and you looked at the insects, I mean the forest itself would probably look very much to a tropical forest if you walk through a trail, a forest trail in Borneo. It would look pretty similar to that.

But if you looked up close, you wouldn't recognize necessarily a lot of the insects. They would be a lot more primitive than ones you'd see today, and they would actually have they would look fairly exotic.

PALCA: Really? So tell us about some of the guys you found so far.

Dr. GRIMALDI: Well, for example, we found actually quite a diversity of highly social insects, like certain kinds of termites, bees and ants. And some of the bees are quite primitive honeybees, the closest relatives of which occur in Northern Europe in Baltic amber. Baltic amber is about 42 million years old.

PALCA: I'm just thinking that this is like having a time machine.

Dr. GRIMALDI: Oh, without a doubt.

PALCA: So you're picking up something, it's like we have some sitting on the desk here, and you're just picking up something and looking into the past. That's just wild.

Dr. GRIMALDI: Exactly, and you could even find pieces that have many, many insects and plants and things in it. It's like an actual little snapshot of that ancient ecosystem.

PALCA: And you can see enough of what's in there to describe the shape and what kind of antennae they had or what kind of body plan, that sort of thing?

Dr. GRIMALDI: Oh, it's incredible. You can look at this in high magnification, under a scanning electron microscope. Like I said, we can actually extract these insects. And if I didn't tell a scientist that this is an image of a 50-million-year-old insect, they wouldn't know, other than by seeing that it's an unusual thing.

PALCA: Wow. So how do you date, how do you date this amber?

Dr. GRIMALDI: Well, we date amber deposits pretty much using the sediments. You can't really date the amber itself. Carbon-14 only goes back to 40,000 years. But we date it with little tiny crystals called zircons, and you can do potassium-argon, argon-argon isotopic dating.

PALCA: Okay. Well, let's go to the phones now, and we have a call from, let's see, Lou(ph) in Manorville, New York. Lou, you're on the air with SCIENCE FRIDAY.

LOU (Caller): Yeah, how are you doing? Just wondering if you find any mosquitoes or biting flies that might contain blood deposits or DNA from the animals, larger animals around that time.

PALCA: Lou, you took my question. Okay, what about that?

(Soundbite of laughter)

Dr. GRIMALDI: You mean a la "Jurassic Park"? Yeah, we do. We do find horseflies, mosquitoes and no-see-ums and sand flies and things like that. And sometimes, not so far in this deposit, but in other amber deposits, we actually see bloated females.

Very often, these blood-feeding flies, it's the females that feed on the blood, and they need the blood to produce their eggs. And when we find these bloated females, unquestionably they contain blood. And you can actually section then, very, very thin sectioning, and look at it with high-powered microscopes and see blood cells. But I don't think you can extract the DNA.

PALCA: Okay, so we're safe from a "Jurassic Park" at the moment.

Dr. GRIMALDI: So far.

PALCA: Thanks, Lou. Let's take another call now and go to DJ(ph) in Sycamore, Illinois. DJ, welcome to SCIENCE FRIDAY. You're on the air.

DJ (Caller): Thanks. I enjoy the show. I had a couple questions. I'm a hobbyist with amber. I was able to buy a few pounds of it - it's Colombian I believe - a few years ago. I mean, I'm always working on it, and I've bought pieces in the past where it'll say - it's identified as this kind of an insect or that kind of a whatever.

I file it down to get it clean enough to look inside. I'm never sure if there's a resource that a person can use to identify the insects. And there's a lot of other things in there. You mentioned molds. I don't know if they're molds or flower petals or just dirt. How can a person find out - are there resources to find out and identify what I'm finding?

Dr. GRIMALDI: Yeah, I mean, if you Google amber, you'll - you might get some references on there. I mean, there's a lot of insect references for identification. And there are some good general references on amber, life in amber in general.

So and sometimes it can be very misleading. You know, very often I get collectors coming to me, saying oh, boy, we found this incredible thing, and it turns out to be some sort of misshapen piece of dirt that looks like something. So you do have to be careful.

PALCA: Okay, DJ, thanks for that call. I'm sorry, I didn't mean to cut you off there. Let's go now to Elijah(ph) in Lawrence, Kansas. Elijah, welcome to the program. You're on the air.

ELIJAH (Caller): Hi. Yeah, it's my understanding there's the theory of the evolution of wings in insects is still kind of unknown. I was wondering if you expect to find any specimens in the sample that might help elucidate where that which theory might be correct or...

Dr. GRIMALDI: No, not in this amber because this is way too young. It's likely that insects evolved their wings about 400- to maybe 380-million years ago, about 400-million years ago, I'd say. And this is a little more than one-tenth the age of that. So it's far too young for that.

PALCA: Okay, good question, though, Elijah. Thanks for that. Let's go now to Gail(ph) in Denver, Colorado. Gail, welcome to SCIENCE FRIDAY. You're on the air.

GAIL (Caller): Hi, thank you for taking my call. My question today is regarding the deposit of amber. I was just curious, like, how large is the deposit? And how long do you think it would have taken for that much sap to accumulate to create that size of a deposit?

Dr. GRIMALDI: That's a good question. It's a huge deposit. The mines we're working again are these huge lignite mines. It's like semi-fossilized coal, and it's used for incineration. They burn it to generate electricity. And they cover many, many hundreds of acres each.

And the ones we're working in are 20, 30 kilometers apart, but it's the exact same deposit, and it probably extends for many dozens of miles all around. So we're talking hundreds of square miles.

And the forest, we know that today, dipterocarps, the trees, the kind of trees that produce this amber, produce huge quantities of resin. In fact, it's tapped, and it's sold as dammar. Dammar is the type of finish or varnish that you put on paintings or on violins and things like that.

So these forests produce a large amount of resin, and they're very large trees. They get to be huge. I estimate, actually, that about 10 percent of the energy produced in these gargantuan electric plants that's burned is actually fossil resin.

PALCA: And so how long I'm sorry, I didn't mean were you going to ask that, Gail?

GAIL: Well, yeah, I was just curious: How long would it have taken to accumulate and amass that size of a deposit?

Dr. GRIMALDI: Well, the deposit itself is only a few million years old. And the amber is concentrated in a few little strata, some thin strata. So it actually was fairly quick.

PALCA: I see. Okay, interesting.

GAIL: Wow, thank you.

PALCA: All right, well, Gail, thanks very much for that. So what's the plan now, just to continue to chip away at the stuff you have, or are you going back to get more?

Dr. GRIMALDI: Oh, we're going back to get more. We usually do it in January, when it's not 120 degrees.

PALCA: Slacker.

(Soundbite of laughter)

PALCA: Okay, well, it sounds like an interesting is any of this on display at the museum?

Dr. GRIMALDI: No. No.

PALCA: Too bad. Well, it will be someday, right?

Dr. GRIMALDI: Perhaps.

PALCA: Perhaps. Okay, we don't mean to put you on the spot. Well, we've run out of time. Thank you very much for stopping by for us today. It's very interesting.

Dr. GRIMALDI: My pleasure.

PALCA: Dr. David Grimaldi is the curator in the Division of Invertebrate Zoology at the American Museum of Natural History in New York, and he joined me in the studio here in New York.

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