Scientists Discover How a Tiny Freshwater Animal Performs a Somersault 04/04/2021 Hydra attached to a surface. Photo: Coveredinsevindust/Wikimedia Commons, CC BY-SA 3.0 What do hydra, tiny freshwater organisms that look like inverted jellyfish, have in common with four-time Olympic gold medallist Simone Biles? Their incredible ability to somersault, it seems. Hydra are smaller than the width of a human finger but can bend their bodies and perfectly flip over their tentacles. Now, with a combination of biophysical experiments and computational modelling, researchers have found that differences in tissue stiffness along hydra’s body length makes this unique motion possible. Named after the serpent-like monster in Greek mythology that regrows two heads for each one that’s cut off, hydra are known for similar powers of regeneration. Slice open a hydra and each half will grow into two new bodies. In addition, they don’t exhibit ageing, leading some biologists to label them ‘immortal’. This drew Suyash Naik, an undergraduate student at the Indian Institute of Science Education and Research, Pune, into studying the organism.