244 THE ANIMALS AND MAN 



animals, but both intelligence and reason are too often shown 

 by many of the other mammals not to make us aware that 

 man's mental powers differ only in degree, not in kind, from 

 those of other animals. 



Pure instinct is hereditary, and purely instinctive actions 

 are common to all the individuals of a species. Those 

 actions which the individual could not learn by teaching, 

 imitation, or experience are instinctive. The accurate peck- 

 ing at food by chicks just hatched from an incubator is 

 purely instinctive. Purely instinctive also is the laying of 

 eggs by a butterfly on a certain species of plant which may 

 have to be sought for over wide acres, so that the caterpillars 

 when hatched shall find themselves on their own special food- 

 plant. Yet the butterfly never ate of this plant and will 

 never see its young. Such elaborate instincts as these have 

 been developed from the simplest manifestations of sensation 

 and nervous function, just as the complex structures of the 

 body have been developed from simple structures. 



The feeding and domestic habits and the whole general 

 behavior of animals are extremely interesting subjects of 

 observation and study. And such observation intelligently 

 pursued will be of much value. The point to be kept ever 

 in mind is that all animal habits are connected with certain 

 conditions of life; that in every case there is an answer to the 

 question "why." This answer may not be found; in many 

 cases it is extremely difficult to get at, but often it is simple 

 and obvious and can be found by the veriest beginner. 



Classification.- -The mammals of North America repre- 

 sent eight orders. Three additional mammalian orders, 

 namely, the Monotremata, including the extraordinary duck- 

 bills (Orniihorhynchus) and a species of Tachyglossus in 

 Australia and Tasmania; the Edentata, including the sloths, 

 armadillos, and ant-eaters found in tropical regions; and 

 the Sirenia, including the marine manatees and dugongs, are 

 not represented (except by a single manatee) in North 



