World Records
The Longest-Living Animals on Earth: From 500-Year Clams to the Immortal Jellyfish
In 2006, researchers dredged a clam from the seabed off Iceland and counted the rings on its shell. The number stopped them cold: 507 years. The animal, later nicknamed Ming, had been alive since before Columbus sailed. It is the oldest individual animal ever reliably aged — but it isn't even the strangest entry on this list. One creature appears to cheat death entirely, reversing its own aging on demand.