Why is this Giant Tortoise on a Volcano? | BBC Earth Science

This is the giant Galapagus tortoise and it's climbed all the way up the flank of this great volcano and is here wandering around the rim of the crater. But why should it come to such a bleak and inhospitable place?

Tortoises being reptiles can't generate their own body heat internally as we do. Instead, they must get it from their surroundings. And these particular ones have come up here to warm themselves on the hot volcanic rocks among the jets of

steam and sulfurous gas. They live longer than any other animal on Earth, well over 150 years. They weigh up to a quarter of a ton and have shells over a meter across.

They really are giants. Having your body encased in shell obviously brings problems and one of them is how do you mate? Making love in a suit of armor is not easy. But the males have a very ingenious solution.

The underside of the shell is concave, so it fits neatly over the domed top of the shell of the female, who is somewhat smaller. That doesn't make clambering on top of her any easier initially, but once the male is up there, it will

reduce his chance of slipping off. The two shells fit together as neatly as two spoons, so mating can begin. And once started, it can go on for a long time.