THE (^AROIilNA HE.WEIJ 



489 



ability to meet new situations. Thvy dnin sli'cniiis in oi'dcr to I'orKi 

 ])()n(ls of siiilabki depth, and in these ponds they eonstruct houses 

 of sticks and mud. The sticks are obtained by cutting down trees 

 near the water and are sometimes six inches or more in diameter. 

 They are cut with the teeth and it has often been asserted that the 

 lowest and deepest cut is on the side toward the water, so that the 

 tree will fall in the direction that will save work in carrying it. 

 This point is disputed, however, and it is prol)able that if the trees 

 fall toward the water it is because they lean that way and not be- 

 cause the beavers exercise extraordinary wisdom in cutting them. 



The food of beavers is bark which they obtain by cutting trees 

 and which they store up for the winter. They also eat tender 

 aquatic plants. In storing sticks of wood for winter food they do 

 appear to show considerable intelligence, for it is said that they 

 usually place their supply so that it will not be carried aw^ay by a 

 flood. The dam and the banks of the pond are also carefully 

 guarded and strengthened to prevent breaking in time of high 

 water. 



The cause of the early extermination of this species is to be 

 found, in part, in the extraordinary persecution to which they are 

 subjected. The coat of the beaver has always been one of the most 

 valuable of furs, and Macfarlane states that the Hudson's Bay 

 Company exported an average of more than 118.000 beaver skins 

 from Canada each year from 1853 to 1877, while as late as 1903 

 they sold over 49,000 skins. In addition to the fur, beavers yield 

 a product called castoreum, which is used in perfumery and other 

 drugs. It is secreted by glands associated with the reproductive 

 organs. 



The habits of the animals in associating together in colonies, 

 the presence of which a,re indicated by dams and ponds, has also 

 aided in the extermination of the species by making it easier for 

 trappers to locate the animals. Compared with the muskrat and 

 many other rodents, the rate of reproduction is slow, since the ani- 

 mals do not breed until three years old. 



Where they are protected they soon increase, how^ever, and ac- 

 cording to Mr. Macfarlane the Hudson's Bay Company has done 

 a valuable service in limiting the catch and preventing extermina- 

 tion in the Northw^est territories of Canada. It seems altogether 

 possible that the animals might be successfull}^ reared in confine- 

 ment if given a good range and plenty of cottonw^ood, birch, ash 

 and other trees suitable for food and for making dams and houses. 



