Fauna Series No. 5

Fauna of the National Parks — No. 5 The Wolves of Mount McKinley

CHAPTER THREE:
DALL SHEEP (continued)

The Rut

Observations on the rutting of the mountain sheep were limited because during much of the rutting period I was checking on wolf movements along the north boundary, and snow made is difficult to cover much territory. The time of the beginning and ending of the rut was not learned. The rutting was probably early because the following spring the lambing period was early.

On November 15, 1940, I noted that the rut was in progress. On Polychrome Pass one old ram and 2 younger rams were with 5 ewes, and another old ram was very active rounding up a flock of 5 ewes. The following day considerable rutting activity was noted on East Fork River. A large ram herding 4 ewes walked a short distance to a large ram in possession of 4 other ewes. After standing around about 10 minutes he returned to his own harem just over the rise. One old ram had 7 ewes, and another was lying near a single ewe. Eleven large rams, 3 young rams, and 12 ewes were scattered over a small area observed. Some of the rams were not in possession of any ewes at the time.

Sheldon (1930) in 1907 found active rutting from about the middle of November to the middle of December. He noted several encounters between rams, and makes the following comments on the rut (p. 240); "Friendly rams remained among the ewes, serving them indifferently. The fights always occurred when stranger rams attempted to enter the bands. As times new rams intruded among the ewes and shared their privileges without apparent objection on the part of rams already with the band."

The rutting activities of the white sheep are apparently very similar to those of the Rocky Mountain bighorn. One ram may serve a number of females and two or more rams may serve the same one. The ewes come in heat over a period of about a month, but judging from the lambing time it appears that most ewes come in heat during a two-week period.

Gestation Period

In 1907 Sheldon (1930) observed the sheep actively rutting in the latter half of November and early December. How late in December active rutting took place is not known because Sheldon's observation of the sheep was interrupted by trips after moose. The following spring he observed the first lamb on May 25. In 1940 I observed sheep rutting in mid-November but do not have data on the duration of the rut. The first lamb the following spring was seen on May 8. The gestation period seems to be between 5-1/2 and 6 months.

Lambs

PRECOCITY

Lambs a day or two old, so small that they can walk erect under their mothers, clamber up cliffs so precipitous that even the mothers can scarcely find footing. Not only can the lambs climb but they possess unexpected endurance. Frequently very young lambs were seen hurrying after their mothers from near the base of a mountain to its very top without resting.

The travels of a captive lamb illustrate the endurance they possess. On May 13, 1928, a ranger brought to his cabin a lamb only a few hours old. It soon became a pet and amused itself by leaping about on the chairs and beds. It followed him and his cabin mate around all day and showed no desiretso join the other sheep that were sometimes in view. It was raised with a bottle, on powdered milk. When only 2-1/2 weeks old it followed the men for 30 miles over rough ground and through glacial streams. When a month old is became wet in a glacial stream when overheated and died of "pneumonia."

It surprised me when I first observed the speed of the lambs on relatively smooth slopes. On May 28, 1939, when most lambs were a little less than 2 weeks old, I came suddenly upon six or seven ewes and their lambs. My nearness gave them quite a fright, causing them to flee full speed down a gentle slope to the bottom of a draw and up the other side. Although the ewes galloped at full speed, the lambs kept up easily and at times two or three of them even forged out ahead. Upon reaching the bottom of the ravine and starting up the other side, the lambs seemed to have an advantage and "flowed" smoothly up the slope ahead of the ewes. When the group finally stopped to look around the lambs were as fresh as ever, and seemed anxious to make another run. This precocity of the lambs is, of course, of great value in avoiding wolves and other predators.

Figure 31: Ewes with lambs frequently congregate on rugged cliffs when the lambs are young. When they go off to feed, some ewes leave their lambs in the care of other females. [Polychrome Pass, May 1939.]

EWE-LAMB RELATIONSHIPS

During the first week or two, ewes that have lambs are especially wary. When approached, they hurry off with their lambs, often crossing over to another ridge so as to leave a draw between them and the intruder, or else climb high into rough cliffs. Before the lambs are born these same ewes might be rather tame, and as the lambs become older they again become tame.

The lamb is not left lying alone as are the young of deer, elk, and antelope. It remains near its mother, pressing so close to her at times when traveling that it may be almost under her. When resting, the young lamb usually lies against the mother or only a few feet away. This habit of remaining close to the mother is of high protective value should eagles attack.

When the lambs are young, several mothers often congregate in rough cliffs. In such places a few of the ewes may remain with the lambs and the others go out 300 or 400 yards to feed on the gentler slopes. On May 26, 1939, 13 lambs were seen frisking about on some cliffs on a rocky dike on East Fork. With the lambs were 6 ewes—3 lying down just above the group, and 3 standing in their midst. While I watched, one of the ewes moved off 150 yards and commenced to feed. A lamb followed her 10 yards, then dashed back to the others. One lamb ventured out alone 20 yards and a ewe at once became alert and moved four or five steps in its direction, whereupon the lamb hastened back to the group. Four ewes were feeding on a slope about 250 yards away from the cliffs. Occasionally one of them would look toward the lamb assemblage. From a point about a quarter of a mile away three ewes stopped feeding and came galloping across the face of a shale slope, calling loudly as they came. When they were still about 100 yards away two lambs galloped forth, each joining its mother and nursing at once. The third ewe did not have such an alert or hungry lamb, for she smelled of five lambs in the top group, then walked briskly down to the rest of the lambs 15 yards below where she found her lamb, who belatedly came forth to nurse.

Figure 32: A ewe and her lamb in the fall of the year. [Polychrome Pass, September 7, 1939.]

On June 5, 1939, there were 22 lambs on this outcrop of cliffs and an equal number of ewes were seen, but some of the ewes were feeding 200 or 300 yards away. One lamb on this occasion ran out about 60 yards to meet its mother and to nurse.

On July 12, 1939, a band of 52 ewes, lambs, and yearlings were feeding on some rather gentle slopes of Cathedral Mountain. The mothers frequently moved off 100 or 200 yards from their lambs which remained in a scattered group resting on the slide rock. Five or six ewes at different times stopped feeding and called loudly. Each time, a lamb would recognize the call of its mother and gallop down to nurse, usually for a minute or less. The sheep were quite noisy at times, the ewes "ba-a-ing" loudly, and the lambs answering more softly.

The tendency for ewes with lambs to bunch up is probably a natural outcome of their all having the same inclination to remain in the rougher terrain. Later there is more intermingling of the ewes with lambs and those without lambs.

Figure 33: A band of ewes, lambs, and yearlings on Cathedral Mountain. Vegetation on the loose slide rock is dominantly dryas. A wide variety of herbs and some grass are also present. Note how some of the lambs remain close to their mothers. Others rested alone while their mothers fed lower on the slope. [July 12, 1939.]

LOST LAMBS

When a ewe leaves her lamb in a group and goes off to feed she may lose her lamb temporarily. On June 7, 1940, I climbed to a small group of ewes and lambs which ran out of sight when I neared them. I was standing on the spot where they had been, when a ewe, which I had passed on the way up, approached me calling. There was not much room on the cliff where I stood so, when the ewe was seven or eight paces from me, I stepped to one side to let her pass. She was evidently perturbed at finding me where her lamb had been, for she called loudly and came toward me with lowered head which she jerked threateningly upward as though to hook me with her sharp horns. After I had warded her off with my tripod she stood for a few moments calling, then hurried in the general direction the others had taken and no doubt soon found her lamb, for the band had not gone far.

On June 13, 1941, I spent some time on Igloo Mountain observing about 50 ewes and 30 lambs. At first most of them were in a broad grassy basin. One ewe nursed her lamb, walked off 200 yards and fed with another ewe for an hour, never once looking toward the lamb. As I climbed, a small group of ewes and lambs, including the lamb of one of the two feeding ewes, moved upward, feeding higher and higher until they were out of my view. When the two ewes rejoined the main band which in the meantime had moved 200 or 300 yards to some cliffs, one of them found her lamb at once but the other was not so fortunate. Calling continually, she searched through the entire band, duplicating her visits to some parts of it, but still with no success. She finally recrossed a gulch and climbed in the direction taken by the little group with which her lamb had gone. She showed good sense, and no doubt soon found her lamb. After the sheep had rested in the cliffs for some time another ewe suddenly commenced to call at short intervals from a prominent point. The ewe had called a long time when two lambs came forth from a large crevice in a rock a short distance away where they had been lying. The ewe saw them emerge and hurried to join them. One of them was her lamb and it immediately nursed.

Figure 34: Ewe, lamb, and yearling plow through a September snow. [Igloo Creek, September 19, 1939.]

PLAY

The lambs play a great deal, romping with speed and agility. Sometimes they butt each other, coming together after a 2- or 3-foot charge. Occasionally a ewe may play with the lambs. Once one played with three lambs, dashing after one, then another. A lamb would leave its mother, get chased, and rush back again to its parent. Apparently is was great fun.

WEANING

Lambs begin to nibble grass when they are a week or 10 days old, and as the summer progresses they feed more and more on green vegetation. Some of the lambs continue nursing well into the winter and I have seen them when they were yearlings trying to nurse. Sheldon (1930, p. 278) reports lambs nursing in February. Weaning is not an abrupt process. I expect that long before nursing is discontinued the lambs could get along very well without this nourishment. The lambs remain with the mother a year and sometimes in the case of female yearlings, another 6 months. It is not uncommon to see a ewe, yearling, and lamb together during the summer and fall. Often yearlings, 2-year-olds, and other youngish animals, along with barren ewes, may be found traveling together. In the spring male yearlings sometimes join the bands of rams.

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Last Modified: Thurs, Dec 20 2001 10:00:00 pm PDT
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