Some insight into the fluctuating size of this pack was obtained on February 27 when the five animals were followed for 2 hours. During that time two members (one of which was larger than the other) often lagged behind the other three by as much as a mile. These two romped and played considerably, with one carrying a stick or a bone part of the time. Eventually they caught up again to the other three. The behavior of the two lagging wolves would be consistent with the hypothesis that they were either pups or a courting pair of adults. In either case, they seemed to be an actual part of the pack even though they temporarily traveled separately. [Illustration: _Figure 26.--One of the radiotagged wolves was a member of this pack of five. (Photo courtesy of L. D. Mech.)_] The fact that 1059 was observed traveling alone three times from April 17 to May 21 may be further evidence that the pack had a den in the area at that time. The presence of a den allows individual pack members to venture off singly and return each day to a known social center, as Murie (1944) observed, so they do not need to travel with each other to maintain social bonds. Wolves in our area breed during the latter half of February (see below), and the young should be born in the latter half of April. Since dens are prepared a few weeks in advance (Young 1944), pack members might be expected to begin traveling singly in mid-April. Some information on social relations within our radiotagged pack of five was also obtained. One of the members could often be distinguished from the others by its reddish cast and this individual appeared to be the pack leader or alpha male (Schenkel 1947). In urinating, this animal lifted his leg, a position seen almost exclusively in males. Except for only two temporary occasions, this animal always headed the pack, which usually traveled single file. The second wolf in line generally was noticeably small, possible a female, and the third wolf was twice identified as 1059 on the basis of sightings of her collar. The leader often gained a lead on the other wolves, especially during a chase (see below), much as reported for a lead wolf on Isle Royale (Mech 1966a). Upon returning to the lagging members of the pack, this animal usually held his tail vertically, an expression of social dominance (Schenkel 1947). On two occasions he led chases against strange wolves and demonstrated the highest motivation (see below). The leader was also the most active in his reactions when scent posts were encountered. Because the function of scent-marking behavior is still unknown, it is important that detailed descriptions of the natural behavior of free-ranging wolves around scent posts be made available (fig. 27). Thus the following excerpt from field notes by Mech dated February 27, 1969, is presented: [Illustration: _Figure 27.--Feces, urine, and scratching in a conspicuous spot indicate a wolf "scent post." (Photo courtesy of L. D. Mech.)_]