170 THE POPULAR SCIENCE MONTHLY 



Size 



Size is the most obvious characteristic possessed by an animal. 

 Whether we are naturalists or sportsmen, or neither, we instinctively 

 classify all animals as large or small. Likewise there is nothing about 

 our fauna so obvious as the fact that the larger animals are disappear- 

 ing. The bison is gone, except for a few small and protected herds. 

 The elk, moose, caribou, mountain sheep, antelope, cougar and grizzly 

 and black bears are gone, except in sparsely settled regions. On the 

 other hand, rodent pests swarm throughout every city, and the field 

 mice, ground squirrels, cabbage butterflies, house-flies and hosts of 

 other small insects continue to make trouble for the agriculturist. 



Large size increases the value of an animal whose products are use- 

 ful and hence makes it more desirable game for the pioneer who hunts 

 to supply his larder and also for the sportsman who hunts for the sake 

 of trophies. Large size also makes an animal apparently more danger- 

 ous if it has rapacious habits. I say apparently, for the microscopic 

 bacillus tuberculosis kills more people in North America every year 

 than all the beasts of prey have killed on the same continent since Co- 

 lumbus first sighted San Salvador, while the house-fly, disseminating 

 the germs of typhoid fever and kindred diseases, is more deadly than all 

 the wolves, panthers and rattlesnakes. 



Sometimes we find related species having the same habits and liv- 

 ing in the same region, but differing in size. Invariably the larger 

 species is more sought after and diminishes more rapidly than the 

 smaller. Squirrels illustrate this statement very well. In the north- 

 eastern United States three species of tree squirrels were once abun- 

 dant. All had very similar habits, and ate practically the same kind of 

 food. The fox squirrel and the gray squirrel are now on the verge of 

 extinction in many places, while their smaller relative, the little red 

 squirrel, thrives. Likewise the coyote fares better in contact with civili- 

 zation than does the wolf, and the cottontail rabbits thrive where the 

 larger jack rabbits and snowshoe hares are being exterminated. 



Eight species of woodpeckers were once abundant in the forests all 

 over the eastern states. Six of these are still common while the two 

 largest species are extinct except in a few inaccessible swamps. 



Large size means great strength. In the past this has been an ad- 

 vantage, within certain limits, by making an animal invincible to the 

 attack of other animals. It is of no avail in stopping bullets, and hence 

 is a disadvantage to a species that must count civilized man as one of 

 its enemies. 



The animals of the future, not only in North America but the world 

 over, will have a smaller average size, and most large species will cease 

 to exist unless they are domesticated. 



