The freshwater polyp known as hydra — a tiny relative of jellyfish and sea anemones in the animal family Cnidaria — don’t have eyes, yet they use the same visual pathway that allows humans to see. Research reveals that hydras’ stinging cells, which they use to move, to defend themselves, and to stun prey, are light sensitive. It’s a new discovery that sheds more light on the biology of hydras and, potentially, of their fellow cnidarians. Todd Oakley, a professor in UCSB’s Department of Ecology, Evolution, and Marine Biology, co-authored a new paper detailing findings of the study conducted in his campus lab. READ MORE (UCSB Featured News)

Hydra, left, have the same visual pathway as humans.
Their tentacles, right, contain stinging cells (shown here in red) that aid in movement, defense, and predation.
Credit: David Plachetzki