Handout 5-E

How do beaked whales feed?

Baleen whales strain plankton through their bristly baleen; toothed whales swallow their prey in huge gulps. Most whales can ingest vast quantities of food through mouths that match their enormous size. Beaked whales, however, have small mouths and little or no teeth, but they still manage to devour squid and fish. How can they gobble up their meals through their dainty mouths?

Beaked Whale Photo: credit Nan Hauser & Hoyt Peckham, CCRC

John Heyning, curator at the Natural History Museum of Los Angeles County, climbed into the tank of a rescued Hubb's beaked whale to find out for himself. He placed his hand over the whale's mouth which sucked it up like a dustball. Beaked whales use suction, as nurse sharks do, to swallow their prey.

Heyning and James Mead, curator of mammals at the National Museum of Natural History, have determined that beaked whales "use their tongues like pistons to suck in their prey." (source: "Suction Power," National Wildlife, Oct/Nov, 1997)

How do feeding whales keep warm in frigid water?

John Heyning and James Mead have also made a curious discovery about the gray whale's mouth. A gray whale's five-foot-long tongue makes up fully 5% of its body surface area, a significant part of its body to be dragging through icy-cold waters. Slurping up krill in the Arctic Ocean should quickly chill the animal like eating ice cream in winter does to humans. But when the scientists dissected a gray whale tongue they discovered blood vessels clustered around the arteries that carry warm blood from the heart. As the blood circulates, its warmth is passed from the arteries which carry blood from the heart, to the surrounding vessels, which carry blood returning to the heart. These heat-conserving countercurrent exchanges are also found in other whale extremities-fins and flukes. (source: "Mighty Mouths: How Whales Keep the Heat," Science News, Nov. 8, 1997)

http://www.gma.org/marinemammals/profiles.html

Worksheet 5-A

Right Whale
Right Whale
http://whale.wheelock.edu/RtWhaleCurr/

p.7

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