Ashes to ashes, dust to dust. That's how it goes. Everything that lives must die.
Everything, that is, except the hydra. (Oh, and these weird jellyfish.) But back to the hydra. We're not talking about the Greek sea serpent. We're talking about the other hydra: the little water-loving creatures that look more like plants than the animals they are.
As Smart News has written before, plants and animals don't all age the same. Some get weaker with time, while some, like desert tortoises, actually get stronger and stronger with age. But hydra don't seem to age at all. In the video above, Robert Krulwich and Adam Cole from NPR explore how the hydra defies age and, scientists think, never actually dies of old age.
As Krulwich notes in an accompanying blog post, the hydra's tale really does raise just so many questions. Biggest of all: “Why the hydra? If nonsenescence, or biological immortality, is an option in nature, how come this particular mini-bit of pond scum got the big prize?”