THE MUSKRAT AS A FUR BEARER AND AS FOOD. 



7 



and those of midsummer are somewhat above the average. The 

 following are actual records secured by the Biological Survey: In 

 February, 3 embryos; March 6, 3 large embryos; April 19, 6 small 

 embryos; June 8, 8 embryos; June 18, 13 embryos. It is probable 

 that the young of early spring litters breed in the fall of .the same 

 year. 



A correspondent from Cambridge, Md., has furnished a detailed ac- 

 count of his observations during many years while residing near 

 marshes and trapping in them. He makes the interesting statement 

 that most of the young muskrats in Dorchester County marshes are 

 born, not in burrows, for there are few places where burrowing is 

 possible, nor yet in winter houses, although this is occasional, but in 

 new nests which the female builds of grasses and dry plants, but 

 without roots or mud. Such a nest is placed above the reach of tides 

 in a brush pile or a bunch of growing plants. He states that he often 

 has found young muskrats in these nests, which are far less bulky 

 than the winter houses. He is uncertain as to the period of gestation, 

 but thinks it is less than a month. 



All recent testimony shows that in their breeding habits muskrats 

 are not unlike field mice. The conclusion is further strengthened 

 by the remarkable way in which the marshes, depleted by vigorous 

 winter trapping, are replenished before the opening of another season. 

 The known facts may be thus summarized: Normally the animals 

 mate in March and the first litter is born in April ; a second litter is 

 due in June or early in July ; and a third in August or September. In 

 favorable seasons a fourth or even a fifth litter may be produced. 

 The period of gestation is possibly no longer than 21 days, as with 

 the common rat and probably with the field mouse. The young are 

 blind and naked when born but develop rapidly. Outside of low 

 marshes, muskrats usually are born in the underground burrows. 



MIGRATIONS. 



Muskrats often wander over fields and along highways far from 

 water. This occurs late in fall, early in spring, or during severe 

 droughts late in summer. The causes are not understood, although 

 the spring movement has generally been attributed to the beginning 

 of the mating season. When met away from water, the animals 

 sometimes show considerable ferocity and have been known to attack 

 persons savagely without apparent provocation. 



The local movements of muskrats, both overland and along streams, 

 make it difficult to protect canals and artificial ponds from the 

 animals. They promptly find their way to new ponds built several 

 miles from their former known haunts. Irrigation canals and ditches 

 likewise are invaded throughout their entire length so nearly simul- 



