58 » EXTINCT BRITISH ANIMALS. 
dam may be frozen over, or the ground covered with 
snow. What is left of the trunks of the trees that 
they cannot drag away, they feed on at leisure, eatmg 
the bark. 
“Besides the work above ground which I have tried 
to describe, they have done a great amount of under- 
ground work, such as cutting channels in their dams, 
and making burrows. These burrows they make by 
cutting a road from the middle of the dam for several 
yards into the dry ground, where they scoop out a 
dome-shaped burrow from eight to ten inches above 
the level of the road, then cut a hole through the 
surface and cover it over with sticks and grass so as 
to act as a ventilator. Here they live and feed in 
security and contentment. Some of the roads to 
these burrows are from fifteen to twenty yards long, 
and so level that the water follows them in the whole 
length. 
‘“ As to the time they bring forth their young, from 
my own knowledge, I cannot say. I have seen it 
stated to be January, and also the beginning of May. 
I can say nothing against that, judging from the size 
of the young when I first saw them in the second 
week of June, the oldest litter being about the size 
of a full-grown rabbit, and the youngest not half that 
size. 
“From careful observation, I have good reasons for 
believing they have only one at a birth. One thing 
I am certain of, they have two litters in the season. 
Beavers are a class of animals that are very timid, 
their sight, scent, and hearing very keen, so much 
