Comparative Success in the Application of Aging Techniques to a Population of Winter-Trapped Mink

Skinned carcasses of 126 winter-trapped mink (Mustela vison) were classified as juveniles and adults by means of a combination of reported aging melthods. The percentage of the sample that could have been aged accurately by using each method of age determination singly was determined. Methods involving the baculum, jugal-squamosal sutures, lateral supra-sesamoid tubercles, region of the epiphyseal closure of the femur, and posterior edge of the ischium were found to be most useful for aging mink. Age determination by dry lens weight was a:ttempted but was found inapplicable under the condition by which mink were obtained. Many investigators have attempted to age wild mammals. Alexander (1958) and Leopold (1933) discussed the need for accurate, readily applicable aging methods. Various techniques, including those re- ported by Petrides (1950), Elder (1951), Lechleitner (1954), and Greer (1957), have been used for aging mink (Mustela vison). Lord (1959) introduced and successfully used the dry-lens-weight method to separate eastern cottontails (Sylvilagus floridanus) into more than two age groups. Other workers have used this method for various animals, but not for mink. Our purpose was to quantitate the relative success experienced when individual aging methods were attempted on a population of winter- trapped mink that had been aged by using a combination of techniques. In addition, we attempted to separate winter-trapped mink into more than two age categories by means of the dry-lens-weight method. MATERIALS AND METHODS. During the 1963-64 and 1964-65 trapping seasons in Kansas (December and January), carcasses of 126 mink were obtained from trappers and furriers in Ellis, Rooks, and Russell counties. Locality was accurate only to county, and date of death for each specimen was recorded as the day prior to receiving the carcass. At the time each mink was brought to the laboratory, the eyes