THE RE-ENTRANTS 315 



Fig. 192. Sea cow. 



Size: Up to 12 feet. Averages 7 to 8 feet, probably when it is subadult. 



Weight: Up to 1 ton. A male 7V^ feet long weighed 432 pounds. 



Distribution: The West Indies, the Atlantic Coast of Central America and 

 Mexico, and the coasts of southern Florida. Summer extensions up the eastern 

 coast of Florida and thinly up the Texas coast. Range does not include northern 

 Gulf of Mexico. 



Identification: Same as for the family. 



Habits: This is a docile, sluggish vegetarian which browses on aquatic vegeta- 

 tion in shallow bays, lagoons, river mouths, and rivers. The upper lip, with its 

 stiff bristles, gathers the food. Manatees travel singly or in small family groups. 

 They are hard to see because of a predilection for turbid water, but otherwise 

 they should not be too difficult to approach under water. Upboiling on the water's 

 surface in series indicates their direction and progress as they swim in shallow 

 rivers or bays. The ribs of manatees are remarkably heavy and dense and 

 probably aid in keeping the animals submerged. Fossil manatee ribs, black 

 and subcylindrical, are not uncommon objects on some Florida beaches. The 

 manatee has been much persecuted for its oil and flesh and deserves vigorous 

 enforcement of the Florida law which protects it. (There is a $500 fine for 

 killing or molesting a manatee.) 



Whales, Dolphins, and Porpoises: Order Cetacea 



The origin of whales is unknown although thev have been in existence for 

 nearly the entire Cenozoic Era (the age of mammals). They form the most 

 fishlike of the re-entrants but are immediately distinguishable from all fishes 

 by the horizontal tail flukes and the movements of the tail, which are up and 

 down rather than lateral. These animals suckle their young in the sea, but they 

 alter the normal mammalian suckling pattern. Instead of the young suckling 

 from the mother, a feat that would be difficult under water, the female pumps 

 milk into the calf by muscular action. This process is very quick. Occasionally, 

 a mother whale and calf will somehow miss connection, and gallons of rich 

 milk flow into the water, turning it white. The nostrils are on the top of the head 

 and form the blowhole which may be opened and closed by a valve. The spout 

 of large whales is the result of the exhalation of air and water vapor from this 

 blowhole. All cetaceans are carnivorous, but the size of prey varies greatly. These 



