The two-headed hydra is not just a myth

The hydra is a small freshwater aquatic species. This animal fascinates scientists with its ability to regenerate its head or foot, when severed. Unlike its mythological cousin, the hydra has only one head. However, a team from the University of Geneva has demonstrated that it is possible to produce two-headed hydras by simply exerting pressure on their bodies. This study reveals the interaction between genetics and tissue mechanics in the development of organisms.