Usually, it's human divers who can suffer from the bends, which can kill. But it can happen to animals too.
When an animal dives, nitrogen gas is squeezed out of their lungs and bubbles into the bloodstream. The deeper and longer the dive, the more gas collects.
Too much nitrogen in the blood can kill, so when they surface whales and dolphins breathe out to get rid of the dangerous bubbles.
But experts at the Navy Marine Mammal Program in San Diego now think noise like sonar and blasts can make the gas bubbles in the bloodstream so big they block blood vessels and crush nerves.
Scientists at the Harvard Medical School in Boston have found proof that loud noises could damage their organs as well as ears.
The Center for Whale Research also found in just one day, 16 whales and dolphins were washed up near where the US Navy had been experimenting.
Go to the link to the right of the story to check out the interactive guide to whales and animals in danger