Lake Maxinkuckee, Physical and Biological Survey 465 



them and all about. The most important element of the winter 

 food of the Muskrat, however, is the freshwater mussels or Union- 

 idaB. At various places along the shore, wherever an object pro- 

 jects out into the water, such as a log or pier, or fallen tree-top, 

 there will be found in autumn or early winter a pile of mussel 

 shells where muskrats have been feeding. These piles are fre- 

 quently of considerable size, containing sometimes a bushel or 

 more of shells. September 24, 1907, one of these piles on Long 

 Point was examined. It was off shore several feet and in water 

 18 inches deep. About one-half of the shells were examined criti- 

 cally and counted. There were 532 shells, representing 4 species 

 as follows: Lampsilis luteola, 358; Unio gibbosus, 167; L. iris, 

 6 ; and L. multiradiata, 1. 



During the fall these operations are probably confined to mus- 

 sels which they find in shallow water near shore. In winter, how- 

 ever, when ice-cracks form and extend well across the lake, the 

 Muskrats go far out on the ice, dive through the cracks and bring 

 up mussels which they eat sitting on the ice. At such times they 

 get mussels at considerable distances from shore. In the first days 

 of January, 1905, a broad crack formed in the ice from Long Point 

 to the Norris boathouse. On January 4, a Muskrat was seen at 

 the edge of this crack about 1,000 feet from shore eating mussels. 

 It would dive through the crack and after a little while reappear 

 with a mussel. Sometimes it dived five or six times before secur- 

 ing one. It would then sit up on its haunches, holding the mussel 

 in its paws and, by much clawing and chewing, finally succeed in 

 opening the shell and removing the meat, which it usually licked 

 out quite clean. In some cases the muskrat failed to get the shell 

 open. Usually the shells are but little or not at all broken; even 

 the hinge still holds and the shells are scarcely injured. It is our 

 observation that the Muskrat, by inserting its claws or teeth be- 

 tween the valves succeeds in cutting or tearing loose the adductor 

 muscles so as to permit the valves to spring open. Another Musk- 

 rat was observed further out on the same crack, a long distance 

 from shore, and the ice along the crack between the two was pretty 

 thickly strewn with shells. The Muskrats apparently do not care 

 so much for mussel-gills filled with eggs or glochidia, as these are 

 usually rejected. The stomach of a Muskrat examined at Wash- 

 ington, D. C., late in the spring was found well-filled with mussel 

 remains. Muskrats also feed to a considerable extent on fish, 

 crawfish and frogs. We have on more than one occasion found 

 partly devoured fish at their feeding stations, and remains of fish, 

 frogs and crustaceans in their kitchenmiddens. We have never 



