148 ECONOMIC MAMMALOGY 



whalers turned their attention to this animal, their numbers were re- 

 duced 50 per cent in ten years. From 1870 to 1880 100,000 were killed. 

 Sea otters, once abundant, are approaching extinction. 



The fur seal of the North Atlantic was at one time threatened with 

 extinction for its fur. Its rapid destruction led to a serious crisis in 

 the amicable relations between the United States and Great Britain, 

 but fine statesmanship finally averted disruption and resulted in the 

 protection of the seals by laws and international treaties. Even the hair 

 seal, not valuable as a fur-bearer, has long been the subject of constant 

 assault for its oil and leather. In 1889 it was estimated that 875,000 

 were killed annually. Unlike rodents and some other animals, the 

 marine mammals are not rapid breeders and cannot long survive de- 

 struction in large numbers. 



While all this destruction of useful mammals was in progress, ap- 

 parently with little thought of the future, useful birds and fishes and 

 extensive forests were also being wastefully destroyed. It is only with- 

 in comparatively few years that the seriousness of the situation, long 

 apparent to naturalists, began to impress the general public and make 

 itself felt in legislative halls. With wider diffusion of a knowledge of 

 the facts, public sentiment is beginning to crystallize into better laws 

 and better enforcement, but very much remains yet to be done if some 

 of our useful species of mammals are to be preserved from total ex- 

 termination. No effort should be spared to get the exact facts before 

 all people in such form that they may realize the urgent need of con- 

 servation of the more useful forms of wild life. 



Unfortunately, while the general assault on useful animals all along 

 the line has been going on, but little systematic, wide-spread, con- 

 certed effort has been made to prevent the dissemination and increase of 

 destructive animals, except the large predatory species. During a cen- 

 tury and a half the brown rat, said to be the most destructive mammalian 

 pest in the world, and the house mouse, also very destructive and a 

 great nuisance, have been allowed to spread from Europe almost over 

 the whole civilized part of the globe, and to multiply enormously. Pre- 

 dacious birds and mammals that feed largely upon rats, mice, gophers 

 and other harmful rodents, have been destroyed by the thousands, 

 leaving these prolific animals to increase without the hindrance of their 

 natural enemies. In some cases man has deliberately introduced harm- 

 ful species into new territory, with disastrous results, as witness the 

 European house sparrow in America, the rabbit in Australia, the mon- 



