Which animal has the longest lifespan?

Humans tend to think a life of 80 or 90 years is long. Some animals would barely consider that middle age. Here are the record holders, and how scientists figure out their ages.

The Greenland shark: the oldest vertebrate

The Greenland shark lives in the cold, deep waters of the North Atlantic and Arctic. It grows only about one centimeter a year and may not reach adulthood until it is well over a century old.

In 2016, researchers estimated the ages of these sharks using radiocarbon dating of proteins in their eye lenses, which form before birth and never change. The largest shark in the study was estimated to be about 400 years old, with a possible range of roughly 270 to 500 years. That makes it the longest-living animal with a backbone that we know of.

Bowhead whales: the longest-lived mammals

Bowhead whales, which spend their lives in Arctic waters, can live for more than 200 years. Scientists first suspected this when they found old stone harpoon tips, of a type not used since the 1800s, embedded in whales caught in modern times. Later studies of the whales’ eyes supported ages above 200.

Ocean quahog clams

A clam might not sound exciting, but the ocean quahog is a champion of long life. One individual, nicknamed Ming, was found off Iceland in 2006 and was later found to be 507 years old by counting the growth rings in its shell, much like the rings of a tree.

Glass sponges and corals

Some of the oldest animals on Earth don’t move at all. Certain deep-sea glass sponges are believed to be thousands of years old, and some deep-water black corals have been dated at more than 4,000 years. Because they grow so slowly in cold, stable water, they can survive for millennia.

The “immortal” jellyfish

The tiny Turritopsis dohrnii, often called the immortal jellyfish, has a remarkable trick. When it is injured, stressed or old, it can turn back into an earlier life stage, called a polyp, and start growing all over again.

In theory this cycle could repeat forever. In reality, these jellyfish are still eaten by predators or killed by disease, so no individual is truly immortal.

Why do some animals live so long?

The longest-living animals often share a few traits:

• They live in cold water, which slows their metabolism.
• They grow and reproduce slowly.
• They have few natural predators as adults.

Studying them may one day help scientists understand aging in humans, too.

The short answer

If you mean animals with a backbone, the Greenland shark wins at an estimated 270 to 500 years. If you include all animals, slow-growing sponges and corals living for thousands of years take the crown.