BROOD-CARE AMONG MAMMALS 177 



is rather large, seven or eight being the usual number, and these lie 

 tightly packed inside the meshes of the nest. Dormice make a 

 nest of the same kind, but generally oval rather than globular, and 

 suspended high up in a thick hedge. 



The elaborate dams which beavers make by cutting down trees, 

 collecting twigs and plastering over the tangled mass with mud, keep 

 the water at a constant level, and in the pools thus formed the 

 carefully built lodges are constructed. These always have an 

 entrance under the water and at least one on land. Small 

 branches are fastened to the dam and stored in the lodge, and in 

 winter when food is scarce the beavers take these above water and 

 strip off the bark and eat it. The special chambers in which the 

 young are born are lined with chips of wood quite differently 

 arranged from the stores of edible twigs. The young are 

 born naked and blind ; the mother suckles them and keeps 

 them warm for a month and then brings them twigs, the bark 

 of which they begin to eat. In six weeks they follow her out to 

 her usual haunts, but remain under her superintendence for two 

 years, after which they pair and set up in life for themselves. The 

 intelligence of beavers is much higher than that of other rodents, and 

 the long period of youth, under the tutelage of the mother, is 

 occupied in learning not only what is necessary to the individual, 

 but the art of living with other beavers in a well-disciplined com- 

 munity, doing work for the common good. 



The beaver towns are only an extreme result of the gregarious 

 habits found in most members of the group. Even when the period 

 of youth is very short, and the mother is soon occupied with the 

 cares of a new family, the deserted young remain together for a 

 time. Young hares, when the mother has left them, haunt the 

 form in which they were born, and play together for a good many 

 months until they are nearly full grown, when they have to scatter 

 because of the special risks of their mode of life in the open fields 

 and woods. More often rodents live together in some kind of 

 community, and it is very rare to find only a single pair in any suitable 

 place. Sometimes they burrow close together, forming assemblages 

 like the warrens of rabbits, or the villages of prairie-dogs or marmots. 

 Sometimes it is merely that they occupy the same corner of a wood 

 or field, the same group of trees or heap of rocks. They retain a 

 kind of communal instinct. Squirrels will desert a wood in a body, 

 and in the north great armies of them, simultaneously, for no apparent 

 reason, but especially in severe winters, move in a direct line over 



C.A. M 



