The longest living animals on Earth

an immortal jellyfish Turritopsis dohrnii floating on a black background — The immortal jellyfish Turritopsis dohrnii can potentially live forwever, turning back into polyps if damaged or starving.

(Image credit: Yiming Chen/Getty Images)

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Saltwater crocodile
Seychelles giant tortoise
Red sea urchins
Bowhead whale
Rougheye rockfish
Freshwater pearl mussel
Greenland shark
Tubeworm
Ocean quahog clam
Black coral
Glass sponge
Turritopsis dohrnii
Hydra

The longest-living animals are equipped with traits to hold off, and sometimes even stop or reverse, the aging process. While humans may have an "absolute limit" of 150 years, this is just a blink of an eye compared with the centuries and millennia that some animals live through.

The true age champions live in water, often at great depths where conditions are stable and consistent. Scientists can't record the birth and death of every member of a species, so they typically estimate maximum life spans based on what is known about a species' biology. From old to oldest, here are 13 of the longest-living animals in the world today.

Cassius — the world's largest captive crocodile — is believed to be up to 120 years old. He was captured in 1984 on a cattle ranch southwest of Darwin, Australia, and has been kept at the Marineland Crocodile Park on Green Island ever since. He was 16 feet, 10 inches (5.13 meters) at the time, leading experts to estimate he was between 30 and 80 years old. As of 2023, he was thought to be up to 120 years old. Cassius is also still growing, providing scientists with "serious knowledge on longevity," Toody Scott, a crocodile keeper who looks after Cassius previously told Live Science.

Tortoises are famed for their longevity. The oldest living land animal is a 190-year-old Seychelles giant tortoise (Aldabrachelys gigantea hololissa) named Jonathan. The tortoise lives on the island of St. Helena in the South Atlantic Ocean after having been brought there by people from the Seychelles in 1882. Jonathan's age is an estimate, but a photograph of him taken between 1882 and 1886 shows he was fully mature — at least 50 years old — in the late 19th century, Live Science previously reported.

Red sea urchins (Strongylocentrotus franciscanus) are small, round invertebrates covered in spines. They live in shallow coastal waters off North America from California to Alaska, where they feed on marine plants, according to Oregon State University. Researchers used to assume that red sea urchins grew quickly and had modest life spans of up to about 10 years, but as scientists studied the species in more detail, they realized these urchins continue to grow very slowly and, in some locations, will survive for centuries if they can avoid predators, disease and fishers.

Studying these long-lived whales could provide hints about how to prolong human life. "My own view is that different long-lived species use different tricks to evolve long life spans, and there aren't many genes in common," João Pedro de Magalhães, an expert in aging science at the University of Birmingham in the U.K., previously told Live Science. "But you do find some common pathways, so there may be common patterns."

The rougheye rockfish (Sebastes aleutianus) is one of the longest-living fish, with a maximum life span of at least 205 years, according to the Washington Department of Fish and Wildlife. These pink or brownish fish live in the Pacific Ocean from California to Japan. They grow up to 38 inches (97 centimeters) long and eat other animals, such as shrimp and smaller fish, according to the Committee on the Status of Endangered Wildlife in Canada, an independent advisory panel that assesses the statuses of species threatened with extinction in Canada.

A 2016 study of Greenland shark eye tissue, published in the journal Science, estimated that these sharks can have a maximum life span of at least 272 years. The biggest shark in that study was estimated to be about 392 years old, and the researchers suggested that the sharks could have been up to 512 years old, Live Science previously reported. The age estimates came with a degree of uncertainty, but even the lowest estimate of 272 years still makes these sharks the longest-living vertebrates on Earth, Julius Nielsen, a researcher at Greenland Institute of Natural Resources, previously told Live Science.

Tube worms are invertebrates that live on the ocean floor. Bacteria in their tubes create sugars from chemicals, which they absorb as food, according to the Woods Hole Oceanographic Institution's Dive and Discover website. Some tube worms live around hydrothermal vents, but the longest-living species are found in colder, more stable environments called cold seeps, where chemicals spew from cracks or fissures in the seafloor, according to the Exploring Our Fluid Earth website hosted by the University of Hawaii.

Ocean quahog clams (Arctica islandica) inhabit the North Atlantic Ocean. This saltwater species can live even longer than the other bivalve on this list, the freshwater pearl mussel. One ocean quahog clam found off the coast of Iceland in 2006 was 507 years old, according to National Museum Wales in the U.K. The ancient clam was nicknamed Ming because it was born in 1499, when the Ming dynasty ruled China (from 1368 to 1644).

Corals look like colorful, underwater rocks and plants, but they are actually made up of the exoskeletons of invertebrates called polyps. These polyps continually multiply and replace themselves by creating a genetically identical copy, which over time causes the coral exoskeleton structure to grow bigger and bigger. Corals are therefore made up of multiple identical organisms rather than being a single organism, so a coral's life span is more of a team effort.

Turritopsis dohrnii is called the immortal jellyfish because it can potentially live forever. Jellyfish start life as larvae before establishing themselves on the seafloor and transforming into polyps. These polyps then produce free-swimming medusas, or jellyfish. Mature T. dohrnii are special in that they can turn back into polyps if they are physically damaged or starving, according to the American Museum of Natural History, and then later return to their jellyfish state.

The jellyfish, which are native to the Mediterranean Sea, can repeat this feat of reversing their life cycle multiple times and therefore may never die of old age under the right conditions, according to the Natural History Museum in London. T. dohrnii are tiny — less than 0.2 inch (4.5 millimeters) across — and are eaten by other animals, such as fish, or may die by other means, thus preventing them from actually achieving immortality.

Hydra is a group of small invertebrates with soft bodies that slightly resemble jellyfish and, like T. dohrnii, have the potential to live forever. These invertebrates are largely made up of stem cells, which continually regenerate through duplication or cloning, so these animals don't deteriorate as they get older. They do die under natural conditions because of threats such as predators and disease, but without these external dangers, they could keep regenerating forever.

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Patrick Pester is the trending news writer at Live Science. His work has appeared on other science websites, such as BBC Science Focus and Scientific American. Patrick retrained as a journalist after spending his early career working in zoos and wildlife conservation. He was awarded the Master's Excellence Scholarship to study at Cardiff University where he completed a master's degree in international journalism. He also has a second master's degree in biodiversity, evolution and conservation in action from Middlesex University London. When he isn't writing news, Patrick investigates the sale of human remains.

The longest-living animals on Earth

13. Saltwater crocodiles: 120+ years old

12. Seychelles giant tortoise: 190+ years old

11. Red sea urchins: 200 years old

10. Bowhead whale: potentially 200+ years old

9. Rougheye rockfish: 200+ years old

8. Freshwater pearl mussel: 250+ years old

7. Greenland shark: 272+ years old

6. Tubeworm: 300+ years old

5. Ocean quahog clam: 500+ years old

4. Black coral: 4,000+ years old

3. Glass sponge: 10,000+ years old

2. Turritopsis dohrnii: potentially immortal

1. Hydra: potentially immortal