236 Studies in Animal Behavior 



of various kinds are of frequent occurrence in one 

 or both sexes, and frequently the secretion of these 

 glands is exceptionally abundant during the breed- 

 ing season. Commonly scent glands are better de- 

 veloped in the male sex. The strong odor of 

 the male goat is notorious. In the male elephant 

 there are glands on the side of the face which, 

 in the breeding period, enlarge and emit a milky 

 secretion. In the males of many species of deer and 

 antelope there are facial glands that are especially 

 active in the rutting season. Other species have 

 scent glands on the feet and limbs, or near the tail. 

 It is not improbable that the secretion of these 

 glands, while not particularly agreeable to ourselves, 

 may have an alluring influence on the opposite sex 

 of the species concerned. There is abundant evi- 

 dence that different species of mammals are able 

 to recognize their own kind through the sense of 

 smell, and it is a well-known fact that many mam- 

 mals are exceedingly quick to detect the scent of an 

 approaching enemy. Any one who has watched the 

 behavior of dogs in taking a sniff at their different 

 acquaintances, or in getting a fuller olfactory Im- 

 pression of a stranger, will realize somewhat to 

 how great an extent experience with odors makes 

 up the dog's mental world. Many facts indicate 

 that mammals distinguish the opposite sex of their 

 own species through the sense of smell, but as the 

 sexes frequently differ in external appearance they 

 are undoubtedly able to recognize one another by 



