Significant aspects of the above observation are (1) the spirited initiative of the leader, (2) the amount of time spent in scratching, urinating, and defecating, (3) the decision of the last two wolves to take a different route from that of the first three even though their goal seemed to be to catch up to the first three, and (4) the fact that the scent posts were located at trail junctions. In the last regard, we often noted from the ground that wolves urinated at the junction of newly formed human trails heading perpendicularly from roads they were following. Copulation in wolves was only observed once during our study, on February 19, 1969. Two members of a group of four were seen coupled for 2 minutes on Kekekabic Lake. On Isle Royale, which is at the same latitude, copulations were witnessed on February 21, 24 and 27 (Mech 1966a). On April 17, a den west of Big Moose Lake known to have been used at least intermittently for 13 years was seen from the air to have fresh activity of some kind in the snow in front of it, and on April 24 we saw a wolf at the mound. A few days later, two local human residents unaware of our interests approached this den and looked in. An adult wolf, presumably the bitch, leaped over their heads and fled the area. The men then dug up the den and removed six pups whose eyes had not yet opened. Intraspecific Intolerance and Indifference Instances of chasing or attack by a pack of wolves on conspecifics not a part of their group have been described by Murie (1944) and Mech (1966a). Observations of such behavior are important in trying to determine conclusively whether or not wolves are territorial. Pimlott _et al._ (1969, p. 75) wrote "It still is not clear, however, whether or not their use of range should be defined as territorial." Mech (1970) summarized the available evidence for territoriality in wolves and postulated that it may be spatiotemporal such that packs might avoid each other at any particular point in time but over a long period might cover the same area at different times. A number of our observations are pertinent to this question, for we have evidence of both, tolerance and intolerance between population units of wolves. Two direct cases of intolerance were observed, both involving the radiotagged pack and other wolves within the usual range of the pack. Following is a direct quote from the field notes of Mech: "Feb. 7, 1969--about 11:30 a.m.--aerial and visual--1059 and 2 other wolves traveling overland about halfway between Heart L. and August L. (R10W-T61 N. Sect. 17 center). They were traveling quickly and intently along a fresh wolf trail, with a lighter reddish individual in the lead. The other 2 animals were darker colored, and one of them was smaller than the other. One of them must have been 1059.