The freshwater polyp Hydra oligactis is essentially immortal and reproduces asexually by cloning itself. Except when it gets too cold: then the animal switches to sexual reproduction, begins to age, and eventually dies. A research team at the University of Innsbruck has now investigated the met...
Source: [Phys.org](https://phys.org/news/2026-10-hydra-immortality-cold-triggers-sexual.html)