[ Daily periods of activity and rest]
According to Charles Schweder, the Caribou do not move about much at night; that seems to be their principal time for sleep. They exhibit a definite tendency to pause and rest also toward the middle of the day. Several instances have already been given of the animals resting at such a time on frozen lakes and rivers: lakes southwest of Reindeer Lake, March 18; lakes south of Lake Athabaska, April 16; Seal River, May 31; Windy Bay, June 6 (mid-morning). Open hilltops are evidently sought likewise for both nocturnal and mid-day rests: knoll by Windy River, June 3; Josie’s Hill, June 20; ridge by Little River, August 24 (about 9 a.m.). (For details, see sections on Winter range, Spring migration, and Fall migration.)
Although we noted a small band of Caribou passing through a thick and extensive stand of spruce at dusk on October 2, Fred Schweder, Jr., remarked that they do not rest in such a place; they are safer from Wolves in open areas. Charles Schweder reported about 50 Caribou, in three slightly separated bands, appearing on the south side of Windy River near Four-hill Creek during the evening of September 24, but not making up their minds to cross; he thought they might have been scared by Wolves. Possibly there was a similar explanation for the crossing of the river at this point by large numbers of the animals during an October night several years previously.
According to Fred Schweder, Jr., a day’s movement of Caribou past the mouths of Little and Windy rivers during the fall migration generally does not commence before 10 a.m. and ends about 3 p.m. The explanation of such a phenomenon is none too obvious; and in any event, there were exceptions enough, though the general statement may hold true for the bulk of the migrants. As remarked in the section on Spring migration, the daily periods when the Caribou crossed the ice of Windy Bay were mainly from 10 to 11 a.m., from 2:30 to 5 p.m., and in the evening.
On August 27, about 5:50 p.m., a majority (say half a dozen) of a small band of Caribou were lying down on a slope near the mouth of Little River. They faced down wind to watch for enemies in that direction, while their noses would warn them of any approaching from the opposite direction. Their attitude was very much like that of Norway Reindeer figured by Seton (1929, 3: pls. 11, 15, 18).
Charles Schweder spoke of having seen whole herds lying down to rest, while none of the animals remained standing up on guard. He had noted one such herd of 600 or 700 along the Thlewiaza River in August. He further stated that when the Caribou lie down to rest and to chew the cud, they hold the head up. They may also sleep in this position. In the hard winter of 1944-45, when the snow was deep and the animals were tired and hungry, he came up to a resting herd. All but one of them got up and moved away. That one remained sleeping, head up and eyes closed; Charles walked up to within 10 feet and shot it. He has also seen resting Caribou lay their heads down on the side, but only for a few moments at a time.
References.—J. B. Tyrrell, 1892: 129; Jones, 1899: 359; Harper, 1949: 227; Banfield, 1951a: 23.
[ Organization of herds]
The Barren Ground Caribou is a distinctly gregarious species. It goes in herds for at least the greater part of the year; this is especially true of the spring and autumn migration periods and of the winter months. We know comparatively little of the behavior of the does at fawning time in June; but probably there is a tendency toward solitariness on their part at that season. It is true that solitary Caribou may be met with at almost any season of the year; but this doubtless represents merely temporary rather than permanent segregation of such individuals. At the very end of the spring migration and at the beginning of the autumn migration, there may be, among the sparse southernmost elements of the population, a larger proportion of solitary animals.
While marching over the Barrens and feeding as they go, the smaller bands maintain a fairly loose organization, as apparently best suiting their needs. On the other hand, the huge herds of former times, such as the Tyrrells met on the upper Dubawnt in 1893 (J. B. Tyrrell, 1897: 49-50, pl. 1; J. W. Tyrrell, 1908: pls. facing pp. 80, 81; Seton, 1929, 3: pl. 22), obviously maintained very compact ranks. In my limited experience, the animals bunched more closely in crossing the rivers than was normally the case on land among feeding herds. While swimming, they would follow each other in files at minimum intervals; but in stepping across rapids they might extend these intervals somewhat.