Part of the show Cybernetics and Computer Vision
Scientists have discovered that sonar from ships and submarines might be causing sperm whales to get the bends. Whales were thought to be immune to this condition, but Michael Moore and Greg Early, from the Woods Hole Oceanographic Institutute in the States, have found evidence of bone damage caused by the bends in a number of sperm whales, some as old as 111 years. The damage to the whales' bones is thought to be the result of surfacing too quickly which, just as in human scuba divers, causes tiny nitrogen bubbles to form in the blood, blocking small blood vessels and damaging the tissues they supply. The scientists think that whales, which often hunt at hours at a time at depths of over a mile underwater, normally control their surfacing behaviour very carefully to prevent themselves from developing the bends. But, if the whales are disturbed by underwater noises like sonar, explosions from sea-floor mapping, or even earthquakes, they might surface too quickly, and develop the condition. It's not just whales that are the victims either. Recently large numbers of dead giant squid have been washing up on beaches in South America with damaged ears, which is thought to be the result of exposure to underwater explosions detonated by companies surveying the sea floor for oil reserves.