280 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1940 



a fresh track like a hound, makes a slow and very careful approach, 

 and, when within reach, grabs its prey, usually with its teeth but 

 sometimes with its hands. This action is so quick that the human 

 eye can scarcely follow it. At the same time the eyelids close al- 

 most completely over the rather prominent eyes, thus protecting them 

 from injury by the sharp claws of insects or other weapons of the 

 prey. If the victim is a mouse or other creature nearly that size, 

 the attack is particularly savage, much like that of a little bulldog, 

 although the grip is not quite so tenacious, the hold being occa- 

 sionally changed to obtain a more effective killing grip. The quick, 

 firm grasp is necessary to prevent the prey from escaping; if not 

 firmly held a grasshopper or cricket might leap or a butterfly or moth 

 might fly or a worm might i-etreat into its burrow. The grasshopper 

 mice contrast sharply in form with the slender, delicate, graceful 

 build of most of the small rodents. Leading predatory lives they 

 are built like little prize fighters. Both fore and hind legs are 

 short ; likewise, the tail. The body is short and powerful. "While the 

 teeth are essentially like those of a deer mouse, they are so modified 

 as to be effective for grabbing, holding, killing, and chewing insects 

 or warm-blooded prey. A grasshopper mouse has need for his 

 large ears to help him detect the faint sounds made by insects or 

 other prey. He also needs good eyesight; and he apparently is 

 able to detect moving objects at a much greater distance than is pos- 

 sible for a pocket mouse or a kangaroo rat. 



The raccoon or coon {Procyon) obtains much of its food along the 

 margins of streams, lakes, and coasts, where frogs, mussels, crayfish, 

 crabs, fish, and other edible creatures are readily obtainable. These 

 are, of course, frequently caught in shallow, dirty water or on the 

 mud and consequently are likely to be dirty or covered with sand. 

 The raccoon has, therefore, formed the habit of systematically wash- 

 ing all its food before eating. It is entertaining to watch captive 

 raccoons take their perfectly clean food to their dish of water and 

 solemnly give it a thorough washing before they eat it. 



Bats (order Ghiroptera) have developed remarkable techniques in 

 meeting the problems of survival in a largely aerial habitat. Some 

 bats that live mainly on fruit have adopted a nomadic type of life 

 in order that they may shift from one locality to another to be 

 where fruit is ripening or to obtain the flowers on which some of 

 them feed. Naturally the bats depending mainly on fruit and 

 flowers must limit their range to the Tropics, for unless they were 

 to hibernate they could not survive the long periods in the temperate 

 zones when fruit and flowers would not be available. 



The greater number of the smaller bats feed on insects that they 

 capture on the wing. To be able to do this they have developed 



