Could immortality ever be possible for humans? It sounds like something from a sci-fi movie, but floating in oceans around the world is a tiny, transparent jellyfish that could hold the answer...

Turritopsis dohrnii, known as 'the immortal jellyfish', isn’t immortal in the true sense of word - it can die - but it has a nifty way of avoiding that fate. In times of stress, this miniscule jelly can biologically reverse its aging process, reverting from 'medusa' (adult jellyfish) to a juvenile form and starting its life-cycle again; potentially ad infinitum.

Abilities like these could hold the key to - if not exactly 'immortality', then at least regenerative or long-life treatments for humans in future. But of course there's a catch: these extremely delicate jellyfish can still easily die from predation, disease, or environmental threats and are extremely difficult to keep healthy in a lab environment.

Hannah and Dara hear about new technology that could change the way we study immortal jellyfish, and discover various other super-abilities in the animal kingdom that could help in our quest for healthier, longer lives.

Contributors: - Miranda Lowe, Principal Curator of Crustacea and Cnidaria at London’s Natural History Museum - Alex Cagan, Assistant Professor in the Department of Genetics, Department of Pathology and Department of Vet Medicine at the University of Cambridge - Maria Pia Miglietta, Associate Professor of Marine Biology at Texas A&M University in Galveston - Nicole Xu, Assistant Professor of Mechanical Engineering, Robotics and Biomedical Engineering at the University of Colorado, Boulder

Producer: Lucy Taylor Executive Producer: Sasha Feachem A BBC Studios Production