REFLEXES, INSTINCT, AND REASON 439 



females, and for the control of his harem others are ready at all 

 times to dispute the possession. But with monogamous animals 

 like the true or hair seal or fox, where a male mates with a single 

 female, there is no such discrepancy in size and strength, and 

 the warlike force of the male is spent on outside enemies, not 

 on his own species. 



The movements of many migratory animals are mainly con- 

 trolled by the impulse to reproduce. Some pelagic fishes, es- 

 pecially flying fishes and fishes allied to the mackerel, swim 

 long distances to a region favorable for a disposition of spawn. 

 Some species are known only in the waters they make their 

 breeding homes, the individuals being scattered through the 

 wide seas at other times. Many fresh-water fishes, as trout, 

 suckers, etc., forsake the large streams in the spring, ascending 

 the small brooks where they can rear their young in greater 

 safety. Still others, known as anadromous fishes, feed and 

 mature in the sea, but ascend the rivers as the impulse of re- 

 production grows strong. Among such species are the salmon, 

 shad, alewife, sturgeon, and striped bass in American waters. 

 The most noteworthy case of the anadromous .instinct is found 

 in the king salmon or quinnat of the Pacific coast. This great 

 fish spawns in November. In the Columbia River it begins 

 running in March and April, spending the whole surrimer in 

 the ascent of the river without feeding. By autumn the in- 

 dividuals are greatly changed in appearance, discolored, worn, 

 and distorted. On reaching the spawning beds, some of them 

 a thousand miles from the sea, the female deposits her eggs in 

 the gravel of some shallow brook. After they are fertilized 

 both male and female drift tail foremost and helpless down the 

 stream, none of them ever surviving to reach the sea. The same 

 habits are found in other species of salmon of the Pacific, but 

 in most cases the individuals of other species do not start so 

 early or run so far. A few species of fishes, as the eel, reverse 

 this order, feeding in the rivers and brackish creeks, dropping 

 down to the sea to spawn. 



The migration of birds has relation to reproduction as well 

 as to changes of weather. As soon as they reach their summer 

 homes, courtship, mating, nest-building, and the care of the 

 young occupy the attention of every species. 



In the animal kingdom one of the great factors in develop- 

 ment has been the care of the young. This feature is a prominent 



