The rare and elusive sharks that live for hundreds of years

This shark may have be roaming the ocean for about 500 years...   Meet the Greenland shark, the oldest vertebrate known to man.

Transcript

00:00Even if you go with the most conservative estimate, which is at least 272 years,

00:08then the Greenland shark is still the oldest vertebrate animal that we know.

00:16It is amazing to have been able to do this work with such a big deep-sea shark

00:22that no one knows very much about it.

00:31Seeing a Greenland shark is super rare because they live in the Arctic and they live in the deep sea.

00:37They have a very rough skin. They do look old, even when they are a small one.

00:51That was a huge surprise. We came up with an estimate of the oldest shark in our study.

00:57The estimate of the oldest shark in our study was somewhere between 272 and 512 years old.

01:04Now we have a number. We have something solid to say, even though we can't say the exact age very accurately.

01:10We can say with very high certainty that it is a very old animal.

01:27There is especially one which is often presented as a 400-year-old Greenland shark.

01:54But the thing is, that particular shark, where there is this very cool image of it,

02:00and it looks very old and very big, that was actually a shark that we released with satellite tags.

02:05Therefore, we have never investigated how old it was.

02:09So it's not correct that that specific animal is very old,

02:13but it's correct that the species Greenland shark can be very old.

02:19People always ask, how is it to see an animal that is 50 years old or 100 years old?

02:25That's impressive. But one thing that is always in my mind more is how long time it can actually live after me.

02:33When you catch a shark of two or three meters, then you're thinking,

02:36oh, wow, this animal can actually live for another 100 years or 200 years.

02:41And I think that is kind of impressive.

02:44That is important in terms of conservation considerations and things like that.

02:48Greenland sharks are a species that are caught as bycatch in some fisheries,

02:53where we expect the females to be actually over 100 years when they are reaching sexual maturation.

03:00And that number should kind of start all warning signs in terms of whether the species is endangered.

03:08But the next question that then comes into play is how many pups do they get per pregnancy?

03:13We know where lions give birth or where crocodiles give birth and how they do it

03:16and how many eggs they get or turtles or things like that.

03:19But when it comes to the ocean and especially when it comes to the deep sea,

03:22all these fundamental questions become relevant.

03:25Here in Greenland, they are most common from 200 meters to 700 meters.

03:30And the deepest record there is of a Greenland shark is almost three kilometers down.

03:35At this moment, I wouldn't consider it endangered,

03:38but it's a species that should be kept under high observation

03:41and especially the reporting methods should be improved.