Diving

Diving

      All marine mammals have special traits that allow them to dive deep and stay underwater for a long time. At some point, all must return to the surface to breathe. Whales and dolphins breathe through single or paired blowholes on the dorsal (back) surface of their head. At the surface, they quickly inhale and relax the muscular flap and close it so that they can dive.  

      While diving, blood is directed away from tissues that can handle low oxygen levels and toward the heart and brain where oxygen is needed most. During diving, the heartbeat slows down. Some are champion divers , mainly the sperm whales. They can dive more than 1600 meters (over a mile) and may remain submerged for an hour or more. Another champion diver, the elephant seal can dive more than 1500 meters (4920 feet) and stay under water for two hours. Bottlenose dolphins can dive to depths of 540 meters (1770 feet) and remain underwater for 8-10 minutes. 

Last modified: Wednesday, 9 May 2012, 6:55 AM