Quintet 225 



which were common to the marsh. This quintet— otter, mink, 

 muskrat, weasel, and beaver— are all competitors to a degree. 

 They have fields of activities, each of which might be repre- 

 sented by segments of the area of a circle. If these circles 

 were laid down so that spaces representing similar activities 

 would intersect, it would be found that each animal would 

 have areas in common with those of others. It would also 

 have space which did not conflict with the other four. For 

 example, I am sure that the members of the quintet, except 

 for the beaver, would and did include frogs in their diet. 

 Perhaps all ate some vegetation, although there would be a 

 vast difference in the proportion consumed by muskrat and 

 weasel. Fish were of prime importance only for the otter 

 and mink, cattails and rushes interested the muskrat and 

 beaver, while the only considerable user of tree products was 

 the beaver. 



As I made my rounds I was particularly struck by these 

 differences. My slow and quiet paddling brought me almost 

 up to a muskrat, known by almost everybody as a semiaqua- 

 tic mammal, three or four times as large as a rat, but thickset, 

 and with a tail laterally compressed to facilitate swimming. 

 It was busy in a way common to no others of the quintet. 

 It stood, surrounded by water, on a little platform of cattails. 

 Much feeding had been done in the vicinity, for the cattails 

 had been cut close to their bases. From its raised dais the 

 muskrat could watch and move quickly into the water where 

 its speed and skill could be used to the greatest advantage. 

 It needs its skill for it has many enemies and, without ques- 

 tion, only the number and size of its litters have enabled it 

 to withstand the heavy pressure of predation. The area is 

 trapped every year, and filling constantly decreases its size. 

 Hawks, owls, and mink regard muskrats highly. 



Muskrats are especially vulnerable when the water is low 

 for they have neither speed for flight nor ability in combat. 

 Inasmuch as they are often a nuisance to cultivated places 



