480 



COLLEGE ZOOLOGY 



A. Duckbill 



6. Manatee 



C. Whalebone Whale 



D. Sperm W hale 



£. \\ alriib 



f. 1 ur Seal 



Figure 352. Some interesting aquatic mammals. A, duck-billed platypus, Oniithorhynchiis 

 anatinus, 24 inches long, with thick fur and webbed feet. It possesses both reptilian and mam- 

 mahan characteristics. B, manatee, Trichechus, 14 feet long. Note flipperlike forelimbs, absence 

 of hindlimbs, and rounded tail with horizontal fin. C, whalebone whale, or right whale, Eubalaena 

 glacialis, 50 to 60 feet long. Note fishlike form, finlike forelimbs, and horizontal bilobed tail. 

 D, sperm whale or toothed whale, Physeter catodon, male 60 feet long. Note fishlike form, 

 flipperlike forelimbs, absence of hindlimbs, and horizontal bilobed tail. E, walrus, Odobenus 

 Tosmarus, 10 feet long, 2000 to 5000 pounds. Note legs adapted for swimming, and long canine 

 teeth (tusks). F, fur seal, Cdlorhinus ursinus, 6 feet long. Note streamlined body, webbed 

 forefeet and hindfeet, and thick fur. (A courtesy of Pacific Discovery, photo by H.C. Reynolds; 

 B courtesy of N.Y. Zoological Society; C, D, E, and F courtesy of American Museum of Nat- 

 ural History.) 



OTHER MAMMALIA 



Mammals differ widely from one another 

 in their mode of life and in their adapta- 

 tions to their environments. Space limita- 



tions allow us to describe only a few groups, 

 but the references at the end of this chap- 

 ter give a wealth of information on mam- 

 malian life. Note the many adaptations 

 mentioned in your collateral readings. 



