THE ocean’s dim depths continue to surprise. This time it is in the form of a crab with a thumb-sized body, thin 15-centimetre-long legs, and eyes that can detect ultraviolet light. But UV light from the sun cannot penetrate to depths of 550 metres, where the pale little crab lives on the bottom of the Gulf of Mexico. So what is it looking for?
Probably bioluminescent prey, says Tamara Frank of Harbor Branch Oceanographic Institution in Fort Pierce, Florida, who collected the crab and a handful of other species to study their eyes. Frank is the first to bring any…
