When animals have a slow metabolic rate, they do not age but rather have a prolonged life. Resistance to diseases and genetics are also factors that can contribute to the longevity of an animal.

Fin whales are the second-largest animals in the world ... Atlantic right whale as critically endangered with less than 400 living individuals.

An curved arrow pointing right. The largest living thing on the planet is not a whale or any other animal you might expect. It is a giant fungus that kills anything in its path, currently taking ...

The largest living thing on the planet is not a whale or any other animal you might expect. It is a giant fungus that kills anything in its path, currently taking up more than three square miles ...

Yai is a hybrid of saltwater and Siamese, and at nearly 20 feet long, he remains one of the biggest living reptiles in ... the world just how massive the animal really was. This impressive ...

From the mighty saltwater crocodile to the massive green anaconda, the world’s biggest reptiles are as impressive as they are ...

A replica fossil of the titanosaur _Patagotitan_, one of the largest dinosaurs ever discovered. It would have weighed about 70 tons (63.5 metric tons.) Spencer Platt/Getty Images News via Getty Images ...

African elephants are the largest land mammals on earth ... Currently the longest living animal in recorded history is an Ocean Quahog Clam from Iceland, with a recorded age of 507 years old.