In an undersea world where hearing is as valuable—sometimes more valuable—than sight, being deaf can be a death sentence. New research finds that many dolphins stranded near shore have hearing loss, and researchers theorize that loss could explain why they're beached. Without the ability to hear, dolphins can't find food or family members, and may ultimately become weak and disoriented, the Washington Post reports. Researchers say old age, disease, and birth defects may cause deafness in dolphins, but man-made ocean noise could also be to blame.
Out of 1,263 animals found stranded in 2007, only 195 were alive—but this research could help those who rescue dolphins to deal with them better. If the dolphin is found to be deaf, "there's almost no point in rehabbing it and releasing it," says the lead researcher, and those dolphins would be better off in an aquarium or other protected space. The study of stranded dolphins found that hearing loss was not a problem in certain species, but bottlenose and rough-toothed dolphins were affected.