I ' 



'-,1 



FiGURK 51.— Pen for holding muskrats 

 temporarily in the field when live- 

 trapped. An elevated, dry compart- 

 ment prevents undue exposure. Note 

 manner of holding the muskrat. 

 (Courtesy Idaho Fish and Game De- 

 partment. ) 



enclosure without serious loss from 

 fighting. During the winter quite 

 a number can be allowed to use the 

 same run after a few days of ad- 

 justment ; as many as 15 or 20 adults 

 have been seen curled up on top of 

 each other inside a nest box during 

 periods of low temperatures. As 

 spring and the breeding season ap- 

 proach this is impossible without 

 fighting. 



Despite careful handling many 

 live-trapped muskrats are lost and 

 the reasons are not always readily 

 apparent. Particular attention 

 should be given to the following 

 points : 



1. Muskrats are handled most easily 

 by carefully picking them up by the tail 

 near the tip ; avoid sudden jerks which 

 can dislocate the vertebrae and result 

 in paralysis of the hind quarters. 



2. The region about the nose is es- 

 pecially sensitive to the slightest blow ; 

 death may result from fracture of the 

 delicate bone structure and from con- 

 cussion. 



3. The muskrat cannot stand long 

 exposure to extreme temperatures 



above water. Intense sunlight, heat, 

 or cold can cause death very quickly. 



4. Many muskrats die from non- 

 apparent injuries sustained in traps, 

 such as internal bruises and torn 

 tissues. 



5. The muskrat usually is not a vi- 

 cious animal when properly handled, 

 but it is highly excitable ; and animals 

 from the same litter often seriously 

 injure each other when excited. It is 

 remarkable how easily one can with its 

 sharp incisors kill another. 



Banding and Tagging 



Experimental studies to deter- 

 mine the radius of spring dispersal, 

 normal range and mass movements, 

 growth rates, and longevity, re- 

 quire the banding or eartagging of 

 the trapped muskrats before their 

 release. Of all the types of bands 

 tried by the various investigators, 

 the Achilles-tendon method of at- 

 tachment has proved the best. Most 

 banding methods can cause serious 

 injury and even loss of the muskrat, 

 and have been discarded in favor 

 of eartagging (fig. 52). The Al- 

 dous holding device has greatly 

 simplified the process. By this in- 



FioiTRE. 52. — A small, metal, numbered 

 tag attached to the ear of a nmskrat 

 is generally used in experimental 

 studies. 



38 



