 The ribs are bound to the spine by flexible cartilage , which allows the ribcage to collapse rather than snap under high pressure . While sperm whales are well adapted to diving , repeated dives to great depths have long @-@ term effects . Bones show the same pitting that signals decompression sickness in humans . Older skeletons showed the most extensive pitting , whereas calves showed no damage . This damage may indicate that sperm whales are susceptible to decompression sickness , and sudden surfacing could be lethal to them . 
