One additional difference in the sex ratio was found between two other subsamples of the wolf-kill--that is, the wolf-kill before and after an unusually high snow accumulation, which reached its peak about February 1, 1969 (table 1). Of a total of 77 animals killed before this snow condition occurred (including those from previous years), 38 percent were females. Of 44 animals killed after the heavy accumulation, 57 percent were females. One possible explanation for this is that females may normally be less vulnerable to wolf predation, for Kelsall (1969) has shown that they probably have a lighter weight-load-on-track than males. Thus when snow conditions changed greatly, making deer generally much more vulnerable to wolves (see Mech _et al._, p. 35), a preponderance of does suddenly might have become available. There is some evidence that does may be generally less vulnerable under most conditions, for all seven of our wolf-killed deer over 10 years old were females, and the oldest was over 14. Condition of Wolf-Killed Deer Because the data show that wolves in our study area tend to kill a disproportionate number of older deer, it is not surprising to discover that wolves also tend to capture a disproportionate number of individuals with abnormalities and pathological conditions (table 8). The explanation for such selection is obvious in regard to the abnormalities of the lower limbs (figs. 14-17): deer with injured or abnormal limbs simply cannot run as fast or as agilely as normal animals (table 7). Our observations show that deer usually depend on their alertness and speed to escape approaching wolves (Mech 1966b, Mech _et al._, p. 1). Any trait or condition that tended to interfere with either alertness or speed would decrease an individual's chance of escape. It is more difficult to explain how dental abnormalities or pathological conditions of the mandible (figs. 8-10) would predispose an individual to wolf predation. However, in the case of dental abnormalities the genetic or environmental conditions that caused the abnormality might also have caused some other trait that increased the animal's vulnerability. Or the abnormal condition itself may have caused a further, more critical, disruption of the animal's physiology or behavior, which in turn predisposed it to wolf predation. The finding of several wolf-kills with poor fat stores could indicate that primary or secondary malnutrition was a factor in the animals' deaths. However, it would take a statistical comparison between the fat stores of the deer at large and those of the wolf-kills to establish this.