Fusion of the distal femoral epiphysis in male and female marten and fisher.

Abstract

The distal femoral epiphyses of 142 marten (Martes americana) and 391 fisher (Martes pennanti), all trapped from November to February in the Algonquin region of Ontario, were radiographed to determine their state of fusion and the presence or absence of scar lines. These criteria indicated that on the average fusion occurred first in female marten, then in male marten, female fisher, and finally in male fisher. Thus the time of fusion in these mustelids was a function of size and possibly also of sex. Radiography of the femur of winter-trapped marten and fisher is not a good method of aging these species because the degree of fusion does not necessarily differentiate juveniles from adults.