Hydra

The hydra, a small freshwater invertebrate belonging to the phylum Cnidaria, is renowned for its extraordinary biological immortality. These simple organisms possess remarkable regenerative capabilities, constantly renewing their cells through rapid cell division. Unlike most animals, hydras show no signs of biological aging - they don't deteriorate in strength or reproductive capacity over time. Their eternal youth is attributed to a high population of stem cells that continuously replace damaged or aging cells. While they can theoretically live forever under ideal laboratory conditions, in nature they typically fall prey to predators or environmental factors. Hydras provide valuable insights for aging research in more complex organisms.