In Greek mythology, the hydra was a monster with many heads that, after a daring hero might strike off one head, two more would grow back in its place. While the Greek’s monster of mythology would have been immense in size, the hydra that exists today is a tiny microorganism that lives in freshwater. Hydras consist of a thin transparent tube with anywhere from 4 to 25 tentacles extending from one end of its body. The body of the hydra can grow up to 2 cm in length with each of its tentacles measuring up to 5 cm. Hydras use their many tentacles to move throughout its habitat but not in the way you might expect. When not crawling along the surface of another creature, Hydras use their tentacles to whip their body through the water in a somersault fashion. Hydras are carnivores, just like penguins, lions, and hawks. Their diet, however, consists of other microorganisms that live in their environment.
Hydras have fascinated scientists for their unique regeneration abilities. In humans, cells are constantly being copied to replace old or dead cells. Over time, however, this process breaks down which is why humans grow old. Hydras however seem to have the ability to replace their cells indefinitely meaning that as long as a hydra isn’t eaten, it can live seemingly forever. And, just as with the greek mythical creature, if a hydra is cut in half, it will become two hydras. If each is cut in half again, you will have 4 hydras!