Summer Movements and Behavior of an Arctic
Wolf, Canis Lupus, Pack without Pups
Main Article
Summer movements and behavior of most Wolf (Canis lupus) packs generally are characterized by individual pack members traveling to and from the pack's current den or rendezvous site where the pups are left; the adult pack members hunt and bring food back to the pups (Murie 1944; Mech 1970, 1988; Carbyn 1974; Ballard et al. 1991). Because most Wolf packs produce pups each year, little is known about Wolf-pack movements and behavior when no pups are present. The following observations of a pup-free arctic Wolf pack were made 5-30 July 1993 in the Eureka area of Ellesmere Island, Northwest Territories, Canada (80° N, 86° W). This pack was habituated to the author and observed each summer from 1986 through 1994 (Mech 1988, 1994, 1995; Packard et. al 1992).
When the alpha female of this pack was first seen on 5 July 1993, from a distance of 2 m, no nipple development was observed, contrary to all other years (i.e., 1986-1992) when the pack had pups (Mech 1995). None of the dens previously occupied in the area (Mech and Packard 1990; Mech 1988, 1993) exhibited any fresh digging or other signs of use during the current year.
In 1992, this pack consisted of only an alpha pair and three pups which survived at least through early August (Mech 1995). During the 1993 study, the alpha pair was accompanied by three smaller individuals (two females and a male) which I judged as yearlings. Two of the 1992 pups had been highly habituated to the author, and one had been less habituated. Of the three putative yearlings in 1993, two were highly habituated and one was less so, providing evidence that these three animals were the 1992 pups, as expected.
The pack or its members were observed for 188 hours in 1993 while they were resting, sleeping, traveling, and hunting. Their movements could best be described as nomadic during this period, for they did not center around a den. However, the pack often used a traditional rendezvous site within about 1.6 km of a weather-station garbage dump. The three yearlings tended to remain together during travels (at about 8.3 km/hr, Mech 1994) and when resting and sleeping; often they slept in contact. Their greetings of the alpha male, especially "licking up," were much more intensive, excited, and prolonged than those when greeting the alpha female. The yearlings spent a great deal of time hunting Arctic Hares (Lepus arcticus), usually 1-2-kg leverets, and tended to do the scouting and chasing, whereas the adults tended more to lie on promontories and wait for the Hares to run by as the yearlings chased them. The yearlings also caught a few Lemmings (Dicrostonyx groenlandicus) and nestlings.
Of the 12 occasions when I observed the pack at the rendezvous site during 5-24 July, the wolves left the site as a pack five times. Twice, the alpha pair left the yearlings at the rendezvous site, once for 4.5 hours and once for ≥32 hours. During the former occasion, only the alpha female returned after 4.5 hours (see below); she and the three yearlings left the site together 24 hours later, apparently before the alpha male had returned. The alpha male did return 24 hours after the rest of the pack had left the site, and he remained there for ≥2 hours but eventually left.
During the five other times when I observed the Wolves at the rendezvous site attempting to leave, the alpha pair tried to depart, but the yearlings would not follow and began howling; the adults then stopped for several minutes, howled, and returned to the yearlings or stopped and slept. My distinct impression was that during these times the alpha pair wanted to travel, but the yearlings did not, so the alpha pair relented.
Once (16 July 1993) when the alpha pair left the yearlings, I followed the pair 9.5 km on an all-terrain vehicle (Mech 1994). The alpha male then dug up a cached front shoulder of a Muskox (Ovibus moschatus) calf. The alpha male delivered the item to the alpha female who ate it for 10 minutes and returned to the yearlings. The yearlings had temporarily split up, but I did observe the alpha female regurgitating to the male yearling near the rendezvous site.
Four times when the pack was observed hunting Arctic Hares, the alpha male ambushed the leverets being chased by yearlings and killed the hares. Three of these times he either immediately dropped the leveret in front of the yearling and the yearling consumed it, or he quickly relinquished it when the yearling approached; once, described below, he gave it to a yearling after 45 minutes of apparently waiting to give it to the alpha female.
The alpha female, however, seldom fed the yearlings. She did not participate as much in the hunts as the alpha male, and she only caught two Hares while I watched. One of these times she ate at least part of the Hare, and another time she kept a Hare from a yearling for several minutes, although in both cases yearlings did manage to wrest part of the Hares from the female. On 12 July I gave the alpha female a 4-kg piece of Seal to see whether she would feed it to the yearlings, but she ate and guarded it for 4 hr + 40 minutes until most of the meat was gone from the bone. The yearlings begged, groveled, and wheedled much of this time, and the alpha female finally relinquished the bone to one of them. This difference between the frequency and readiness with which the alpha male and alpha female fed the yearlings may explain why the yearlings mobbed and licked up to the alpha male more than to the alpha female. Ballard et al. (1991) found that an alpha male provided more food for pups during summer than did the alpha female.
On 13 July, the five wolves traveled to the area around the pack's traditional den (Mech 1988; Mech and Packard 1990) and hunted Hares for 6 hours nearby. The alpha female visited the den at 2200 hours and lay nearby but eventually headed back 0.5 km to the area where the rest of the pack were hunting Hares. Once when the alpha male killed a leveret, he carried it to the den as if to give it to the alpha female. He looked around the den for several minutes and kept the Hare away from the yearlings which kept trying to get it. When the alpha female did not return after 45 minutes, he relinquished the leveret to one of the begging yearlings.
During this same observation, the alpha male and yearling male slept around the den from 0030 to 1220 hours, and the other three pack members from 0440 to 1220 hours on 14 July. From 0329 to 0439 hours, the alpha female entered the den six times for periods of 7-19 minutes each and dug out the den several times. At 1220 hours, the pack left the den and began traveling again until I lost them at 1430 hours, some 21 km travel distance away from the rendezvous site and about 13 km from the den.
This pack was known to use an area of ≥1,600 km² (Mech 1988), and during this study, they ranged over ≥381 km². Based on the directions the Wolves were heading when I lost sight of them, the directions from where they reappeared, and their nearby travel routes and ranges known from previous years (Mech 1995), they probably used an area ≥670 km² and possibly much more.
Several generalizations can be made about the behavior of this pupless Wolf pack. The pack generally traveled nomadically over much of their range as packs usually do during winter and as pupless wolf packs in forested areas also do (Mech unpublished). Second, the social cohesion of the pack seemed at least as great during this period as it was when the pack had a den and pups. Third, the yearlings sometimes behaved like pups in remaining together in a rendezvous site while the alpha pair hunted for many hours and delivered food to them. The latest reported use of a rendezvous site until this study was when the pups were about 32-weeks old (Mech 1970: 143). Fourth, lacking pups, the alpha pair invested their time and food in the yearlings. When pups are present, the yearlings are more independent in obtaining their own food, often deliver food to the pups, and are denied food by the adults (Mech 1988).
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