Image via Wikimedia Commons The hydrozoan Turritopsis dohrnii, an animal about 4.5 millimetres wide and tall (likely making it smaller than the nail on your little finger), can actually reverse its ...

Turritopsis dohrnii follows a typical jellyfish life cycle, beginning as a larva and maturing into a polyp and then an adult medusa. However, it can revert to the polyp stage in response to stress ...