Elderly elephants, lonely giants and the secret of aging

Long body, pointed "snout" and very tasty eggs: sturgeons are mostly known as the source of caviar. They can reach 100 years old - their longevity is even more impressive considering the thousands of kilometers they travel. Sturgeons spawn, meaning they are born in freshwater, swim to the oceans to live out their lives, and return to their home waters to reproduce.

Flying seems to be a good way to stay in shape: among the animals with the longest lifespans are many birds, like the gray parrot. It can get up to 70 years old. The oldest known cockatoo resided in the London Zoo, and lived well past his 80th birthday. And ravens can become 90 years or older.

Bowhead whales can reach up to 200 years old. But determining their exact age can be challenging - researchers have to conduct a biochemical analysis of the whale's eye. Sometimes, all it takes is a lucky coincidence: A couple of years ago, a piece of a harpoon dating back to 1890 was found in the flesh of a bowhead whale. So that one was definitely more than a hundred years old!

Elephants live together in herds, and are among the few wild species with hardly any natural enemies. If they aren't slain by poachers, they can reach up to 70 years old. Led by an mature female or cow elephant, they wander Africa's savannas in search of water and fresh grass. Perhaps their most human-like trait: they stop and mourn when they pass the place where an elephant from their herd died.

He led a lonely life for more than 100 years: Tortoise "Lonesome George" of Pinta Island in the Galapagos was long considered to be the last of his kind - Chelonoidis nigra abingdonii. Though lonely, he was popular, and was even preserved and displayed after he died. Giant tortoises of other species lived even longer - Galapagos tortoise Harriet died in 2006 at the age of 175.

Although this specimen doesn't look particularly spectacular, it is highly interesting for scientists: the oldest ocean quahog ever found, at 410 years. Every year, the clam forms another "growth ring" at the edge of its shell. Researchers can learn about the climate or sea conditions of past centuries from the shells of old ocean quahogs.

This sponge grows very slowly, but sticks around for a long time. Scolymastra joubini lives at the bottom of the Antarctic sea, and is older than any other animal: an estimated 10,000 years. Researchers at the Alfred Wegener Institute used the sponge's oxygen uptake rate to help calculate its age.