CASTOROLOGIA. icy 



conception of its engineering works, doubtless led to all the early and 

 most of the recent efforts to preserve or perpetuate the species. The 

 original life of our domestic animals and pets — horses, cows, sheep, 

 pigs, dogs, cats and pigeons — furnishes the biologist with problems 

 of the utmost interest ; while the changes which have followed the 

 domestication of animals within the range of our times, baffle even 

 the most advanced speculations. The ostrich and camel in Africa ; 

 the elephant in Asia ; the reindeer in Northern Kurope and America, 

 and the llama in South America, serve to show how nature accom- 

 modates her children to altered circumstances. This quality of 

 adaptation is the fundamental requirement in the matter of domesti- 

 cation, and implies, firstly, that the animal can thrive in great changes 

 of climate and environment ; secondly, that it can adapt itself to a 

 varying food supply; and thirdly, that its nervous system must be 

 strong and improvable. By applying these tests to the beaver, it 

 will be found that it does not come within the requirements, for, as 

 a rule, it does not wander much, though originally it was very 

 widely distributed, and its life is so much dependent on a full supply 

 of fresh water, that this alone would prevent domestication except 

 under very special circumstances. The question of food is also an 

 important consideration, for though under semi-domestication, the 

 beaver is found to thrive on most vegetable substances, still nature 

 prompts the appetite for bark, and to satisfy this, a constant supply 

 of fresh wood of a rather limited kind would be required, and even 

 when this want is provided for, the condition of the teeth soon fails, 

 and might be taken as an infallible sign of degeneration under altered 

 circumstances. Finally, in the chapter on its anatomy, it will be 

 shown that the beaver ranks singularly low in the scale of Compara- 

 tive Psychology, and though this may seem contrary to the popular 

 conception, it must be acknowledged that beavers have never made 

 themselves conspicuous by any exhibition of acquired performances, 

 but only display inherited instinct. The plausibility of the following 

 story is interesting, though its truth is not vouched for. A tame 

 beaver, around a camp, was becoming objectionable through its pro- 

 pensity for cutting everything in the camp, until the followers 

 started it on a rough pile of felled trees ; the beaver was made 

 perfectly happy, and labored away, keeping its teeth in good shape 



