118 



NORTH AMERICAN, FAUNA 66 



No skulls of this species are available from Maryland for measure- 

 ment. 



Habitat and. hahits. — The habitat of the nutria in its South Ameri- 

 can home is in marshes, swamps, and along the margins of rivers and 

 lakes in fresh-water plant associations. Bednarik (1958, p. 2) says, 

 however, that Randall Rhodes, Curator of Collections at the Cleveland 

 Museum of Natural History, has told him (in personal communication 

 1954) that in South America he obsen^ed that nutria were mostly as- 

 sociated with marine waters. The temperature of the water seems to be 

 of little importance to them, and in the United States they are now 

 found as far north as Michigan and Washington State, where they 

 prosper in the same type of habitat as the muskrat. 



The nutria is a vegeitarian, consuming a variety of aquatic plants, 

 rushes, reeds, grasses, seeds, cattails, and sedges. In captivity it shows 

 a marked preference for alfalfa and clover and is fond of practically 

 all root crops except Irish potatoes. Because of its voracious appetit-e 

 it has posed a serious threat to waterfowl marshes in some areas where 

 it has been introduced. 



Nutria living in streams or ponds which have steep banks burrow 

 into them close to the water level. Each pair makes its own burrow, 

 which is dug in and upward until well above the water level. The den is 

 lined with grasses, and as the family grows, the burrow is enlarged. 



If the nutria are li\dng in a marsh which does not have steep banks, 

 floating nests of aquatic vegetation are built, which resemble those 

 made by the muskrat. Where conditions permit, part of a colony may 

 live in floating nests in the marsh, while other animals will build bank 

 burrows. 



The gestation period of this species in Maryland is between 130 and 

 134 days (Dozier, unpublished data, U.S. Fish and Wildlife Service). 

 The young seem to be born during all seasons, and there are probably 

 two or three litters a year per female. In Louisiana, litter size averages 

 4.4 young (Harris, 1956). 



Nutria apparently became established in the Dorchester County 

 marshes of Maryland sometime in the early 1940's, There are no rec- 

 ords of their occurrence there earlier, and Herbert L. Dozier, formerly 

 Director of the U.S. Fur Animal Field Station at the Blackwater 

 National Wildlife Refuge, does not mention their presence in the Mary- 

 land marshes in his extensive nutria correspondence m the files of the 

 Fish and Wildlife Service dating back to the period 13 March 1939, to 

 3 June 1941. It is possible that Maryland's nutria population may have 

 originated as escapees from the U.S. Fur Animal Field Station, al- 

 though there is no certain proof of this. In the late 1930's and early 

 1940's Dozier was conducting experiments at the Blackwater Refuge 

 on the feeding, care, and breeding of captive nutria. In one of his let- 



