And these are just the oldest ones we know of -- it's almost certain that there are much, much older ones out there. Their incredibly long lifespan is linked to what scientists describe as a "slowed cell replacement process," but as of yet, they have no idea what makes them age at such a slow rate. They do know that, once these clams reach their sexual maturity, the enzymes in their body (which are linked to growth) remain stable for about 150 goddamned years, which doesn't mean they manage to survive thanks to their horniness, but that's how we're choosing to interpret it anyway.
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That is so hot.
Some scientists think that clams may be the oldest living animal in the planet, but it turns out that there's another species that has them beat by, oh, a few thousand years ...
Glass Sponges Can Live for 15,000 Years
You may not think of sea sponges as animals, but that's how people who know more than you classify them; they're just very simple ones that happen to look like the stuff you use to wash your dishes. One not particularly sponge-y looking one is the Hexactinellid or glass sponge, which has a rigid skeleton, hence its nickname. We think a better name would be "the fucking Highlanders of the sea," because that's exactly what they are.
Seriously, how long do you think a sea sponge can live? A hundred years? Five hundred? A thousand? Try over 10,000.
And that's even without wearing square pants.
Yeah, glass sponges may not seem very impressive at first glance, but that quickly changes once you find out there are specimens alive today that are older than human civilization -- these things are estimated to live up to 15,000 years, making them the oldest living animals on the planet. They are older than the pyramids or, you know, the concept of humans building stuff, and they're still alive and chilling right now. What's more, scientists think they evolved their current form 700 million freaking years ago, at which point they decided "yep, this is good enough."
One of these guys found in the South China Sea was determined to be 11,000 years old, and scientists used the water inside to find out what water temperatures were like in ancient times. Water isn't the only thing that goes inside of them, though: the spongicolid shrimps like to loiter around inside these sponges, only to find themselves trapped once they grow too big to come out. These shrimp live the rest of their lives trapped inside the fun-house sponge, mating and releasing their unknowing young into a bleak world where their only chance for survival is to also be forever trapped inside a glass house, looking out, but never being free.
Pretty sure there's a metaphor there, but we'll be damned if we can think of one.
You can find Karl on Twitter or read more of his work at Gunaxin. He'd also like to thank Kelly Stone and Dwayne Hoover for helping with this article.
For more animas that'll outlive us all, check out 5 Animals That Are Terrifyingly Hard to Kill and 6 Terrifying Creatures That Keep Going After They're Dead.
Further Reading: Looking for an animal even tougher than the ones on this list? Microscopic water bears can survive nuclear blasts and temperatures near absolute zero, because they're the goddamn boss. But death doesn't mean animals have to go away- click here for the creepiest art dead pets have ever been fashioned into. And if that puts you in the mood for inspirational tales of animal survival, click here to read about Roadrunners beating the shit out of rattlesnakes.