美国国家公共电台 NPR A Slimy Discovery: New Fossil Found Of Jawless, Backless Hagfish

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SCOTT SIMON, HOST:

You might want to set aside your cornflakes for a moment now. Ed Yong writes in The Atlantic about a substance he says, quote, "looks revolting but is also one of nature's more wondrous¹ substances, unlike anything else that's been concocted² by either evolution or engineers." Ed Yong, science writer for The Atlantic, joins us now. What are you celebrating here?

ED YONG: Hi. I am celebrating the slime produced by a type of fish called the hagfish. So the hagfish is, you know, a 2-foot long creature that lives in the deep ocean. It looks a bit like an eel³, but it's not. It has no backbone⁴. It has no jaws⁵. And, most tellingly, it has the ability to produce incredible amounts of this very, very weird⁶ and unusual slime.

SIMON: I guess we could both make a lot of jokes about how similar it is to members of the U.S. Senate, but (laughter)...

YONG: Can neither confirm nor deny that.

SIMON: Slime. A teaspoon⁷ of slime at first, but it really multiplies, doesn't it?

YONG: So a hagfish will release about less than a teaspoonful⁸ of the slime from the glands⁹ on its side. But in, like, less than half a second, that teaspoonful will expand into liters of slime. If you put a hagfish in a bucket, at first, it'll look like these thin wisps of, like, white, cloudy stuff have been released from its flanks. And then, if you stick your hand in and swirl¹⁰ it around, you'll just be pulling out, like, handfuls of this stuff. It's almost like the entire bucket will have converted into slime.

SIMON: But this is what they do to protect themselves?

YONG: Right, it's a defensive¹¹ measure. They release it when they're attacked or when they're stressed.

SIMON: Because a lot of predators¹² might say, ha-ha-ha, no backbone, no teeth? I know what I'm having for lunch.

YONG: Right, exactly. They often get bitten and attacked. But when they do, they instantly release this massive cloud of slime which is very, very good at infiltrating¹³ nooks and crannies, including the mouths and gills of predators. So there have been these incredible videos of sharks biting hagfish and then just recoiling¹⁴, their mouths and gills full of slime and just gagging and being forced to retreat.

SIMON: Sharks essentially¹⁵ saying, I'm sorry (laughter). I'm not a Spielberg shark. They don't pay me enough to swallow slime.

YONG: I think it's more like they're saying, (vocalizing).

SIMON: (Laughter) Now, hagfish slime is in the news because of a new fossil, right?

YONG: So partly, yes.

SIMON: A newly discovered fossil.

YONG: A newly discovered fossil. The fossil is interesting because the evolutionary¹⁶ relationships of hagfish to other fish have long been controversial. Like, a lot of scientists have thought of them as very primitive¹⁷ creatures, like some sort of transition from a kind of worm-like thing to a fish-like thing. But this new fossil helps us understand that it looks like hagfish are vertebrates. They are part of the backbone lineage. They just seem to have lost a lot of the traits that we have, things like complex eyes and bones and taste buds. So rather than being this weird, evolutionary throwback, they're actually very, very well-adapted animals to the somewhat grim and grotesque¹⁸ life that they live at the bottom of the ocean, feeding on corpses¹⁹, sliming things that might want to eat them.

SIMON: Oh, boy, does that sound - ah, what a life that sounds like.

YONG: (Laughter) Right. But I tell you what, I was serious when I said that it's one of evolution's marvels²⁰. I think very rarely do you see a substance with this combination of properties produced by an animal that most people have never heard of.

SIMON: Ed Yong covers science for The Atlantic. Thanks so much for being with us.

YONG: Thanks for having me.