The discovery that 13 percent of the fawns and 84 percent of the yearlings killed during January, February, and March had not yet shed their deciduous incisors and premolars, respectively, also fits well with the rest of our information. Evidently some unusual factor had caused the delay in tooth development and replacement. One possibility is that the animals were born in August or September, much later than normal. Although most deer in Minnesota are born in May and June, there are records of births in July and August. In addition, a fetus 181 to 200 days old was found in a doe killed on September 26 (Erickson _et al._ 1961). An alternate explanation for the delay in tooth replacement is that the animals were suffering from malnutrition or nutrient deficiency. Severinghaus[35] has evidence that yearling bucks that have not replaced their deciduous premolars during November, and thus are aged at 17 months (Severinghaus 1949), generally have shorter, narrower antlers and fewer points than 18-and 19-month-old individuals. Degree of antler development in turn is considered related to nutritional state (Latham 1950). Thus it is reasonable to conclude that animals behind in tooth development and replacement, whether this is caused by age or diet, are physiologically inferior. Most of the abnormal conditions discussed above pertain to the skeletal parts of wolf-kills. If the soft parts of a large number of kills could be examined thoroughly, one might discover a much higher incidence of diseases and other pathological conditions. In conclusion, our data on both age and condition of wolf-killed deer show that at least during winter, wolves in our study area usually do not kill just any deer they discover, although they do try to. Evidently, most deer can usually escape wolf predation. The most frequent exceptions are those 5-1/2 years old and older, those born late, those suffering from poor nutrition, those with abnormalities or pathological conditions, and possibly fawns. The above conclusions parallel those of Murie (1944), Crisler (1956), Mech (1966a), and Pimlott _et al._ (1969) for wolves preying on Dall sheep, caribou, moose, and deer respectively, and further substantiate the claim by Mech (1970) that they can be extended to wolves preying on most, if not all, species of large mammals under most conditions. It is also apparent from the data presented above that deer over 5 years of age and those with abnormalities of the jaw or lower limbs represent such a small percentage of the total population that they are seldom taken by human hunters. In this respect, competition between timber wolves and human hunters appears to be minimal in the study area. FOOTNOTES: [35] _C. W. Severinghaus. Unpublished data_. [Illustration: _Figure 14.--Arthritis in right hind foot of specimen M-28. (Photo courtesy of University of Minnesota Veterinary Diagnostic Laboratory.)_]