Fauna Series No. 5

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

CHAPTER FOUR:
CARIBOU (continued)

Rutting Period

The rutting period begins some time after the middle of September and continues to the latter part of October. On September 14, 1940, two bulls were seen paying attention to cows, but most of the bulls seen were not yet with the females. On October 7, 1940, four small bands were seen, each with a bull in charge. Three of the bands consisted of 11, 4, and 13 cows, and in each band there were two calves. The fourth band was larger than the others but no count was obtained. During the rutting period the old bulls lose the large amount of fat accumulated during the summer period and face the winter in a gaunt condition. The fact that bulls have used up so much reserve energy during the rutting period may have a bearing on their survival through the winter months.

Caribou Calves

DESCRIPTION

The newborn caribou calf is reddish-brown, with a strip of black sometimes 3 or 4 inches wide running down the middle of the back. Some calves are more red than others. They lack the spots found in deer and elk. The blunt, squared-off muzzle is black. A few days after birth the pelage becomes a faded brown. The bulk of the calves are rather uniformly colored, but variations are fairly common. One calf was a bright orange color. Another was exceptionally whitish, and it was significant that the mother of this one was also unusually light colored. The first coat is lost in July, the change taking place first on the face. On July 13 several calves were noted which had lost most of the first coat and had acquired the new pelage which at first appeared almost black. This pelage soon becomes similar to that of the adult, but the white on the necks and sides is absent the first year.

A female calf born on May 18, 1940, had the following measurements: total length, 32 inches; tail length, 3-3/4 inches; hind leg, 14 inches; ear, 3 inches ; shoulder height (from tip of hoof), 24 inches. Another newborn calf was 22 inches high at the shoulders.

The calves have a deep guttural, short call, reminding one of the quality in the bullfrog's note or the deep grunt of a pig. The calves are often quite noisy, especially in a moving herd or in a herd that has been disturbed. A single calf is the rule, no twins having been observed.

CALVING

The calving period is roughly from the middle of May to the middle of June. In 1940 the first calf was seen on May 12, and in 1941 on May 14. Most of the calves were born during the following 2 weeks. The latest record I have is for June 22 when a calf only a day or two old was seen.

Figure 48: A calf caribou less than a day old. Note the black, square muzzle. [May 24, 1939.]

To give birth to their calves, cows generally wander off varying distances from the main herds. At this time a lone cow is almost sure to be near a newborn calf. Generally these lone cows still carry one or both antlers. Within a few days the cows with their calves join the main herds. Sometimes the mothers band together in groups of a dozen or so, and move about together for a short period.

The open rolling tundra in the region about McKinley, Cache, and Clearwater Rivers is often referred to as a favorite calving ground. The caribou calved in that region in 1939, but in 1940 and 1941 most of the calving took place on the gently rolling tundra between Savage and Sanctuary Rivers. Possibly the location of the principal calving grounds depends largely on where the caribou happen to be at the time. The fact that the same areas are used several years for calving may simply mean that the general movements of the herds are similar for those years.

In 1940 large herds of caribou first moved into the calving area between Teklanika and Savage Rivers on May 9. Large bands were last seen in this region on May 29. Most of the caribou had left before the 29th and had moved southward toward the head of Sanctuary River. In 1941 large bands moved into this same region on May 14. Some calved on the north side of the outside range and moved into the area later. On May 28, bands totaling 6,000 animals, not including calves, were seen moving southward between Sanctuary and Savage Rivers. On May 29 about 2,000 adult caribou with calves were seen in the region, and on May 30 only about 100 adults with calves were noted. There is some movement of the herds before all the calves are born, but for the most part during this period there seems to be an interval when the herds wander about locally.

The calves are unusually precocious. On May 17, 1940, I found a calf in a spot which I had passed about 3 hours before, so that it was known to be not more than 3 hours old. There was a packed-down area in the snow about 12 feet across, and a little blood was noted in two places. The calf's legs were still moist. It managed to stand up with considerable effort and after walking a few steps in the snow it fell down. It tried walking several times, seeming to gain additional strength with each effort until finally it was able to follow me around, which it insisted on doing. It gave the typical guttural grunt. While I was with the calf the mother circled about 200 yards away.

The behavior of this calf was similar to that of a number of other newly born calves which were observed. I was unable to check closely on a calf's development, but in a day or two they can follow the mother, and I would guess that in about a week or 10 days they are able to run almost as fast a their mothers. On June 1, I saw calves, chased by a wolf, keeping up with the cows. Most of these calves were not more than 2 weeks old.

RELATION OF CALVES TO COWS

I found no indication of cows leaving their calves while going off to feed, as do antelope, deer, and moose. From the time the calf is born it remains close to the mother. When able to follow readily, the calf as a rule remains close beside or behind the mother like a shadow. This close attachment, is important from the standpoint of survival in a herd animal, for a great many calves would otherwise lose their mothers. Some observers have stated that the calves seem to have little attachment for their mothers and wander off at random. After watching thousands of calves my impression is that the calves do remarkably well in remaining close to their mothers. It is true that when a large herd has been disturbed a few calves become separated, but with several hundred animals milling around it is surprising that more of them are not left astray. On several occasions I have seen cows and calves searching for one another.

On May 29, 1941, I observed an interesting incident in this connection. On the rolling tundra between Savage and Sanctuary Rivers I saw a band of about 700 adult caribou with calves moving westward and then circling northward. They had moved away from two grizzly bears. After the caribou had moved a little less than a mile, I noticed that two calves were lost, a half mile from the main herds. One calf joined up with a cow and calf and followed in their wake for some distance, and then moved off in another direction, obviously searching for its mother, which in the meantime had returned from the main herd and soon found her calf. When the mother came the youngster at once commenced to nurse vigorously. It had been lost at least a half hour. The other calf wandered toward the herd, started for several cows, then circled back toward the place it had left. It then disappeared in a swale and was not seen again. This calf was searching for its mother, and after following the herd had returned to where it apparently had last seen her. A cow, probably the mother of the second calf, was searching but while I watched she did not go back far enough to find the calf.

On July 1, 1940, a lone calf came running in my direction and stopped within 15 yards of me. It apparently was looking for its mother and came to investigate me. It later crossed some broad gravel bars and found her.

The cows are reasonably solicitous when their young are in apparent or real danger. On May 24, 1939, I approached a cow with a calf that was less than a day old. When the cow ran off the calf followed slowly. Part of the time the mother trotted slowly enough for the calf to keep up, even though I was hurrying after them about 75 yards behind. Each time the mother found herself a short distance ahead, as happened four or five times, she returned and nuzzled the calf. When it finally lay down, the cow stopped about 50 yards away and did not run off until I captured the calf. Then she ran over a nearby rise and circled above me, keeping watch from a distance of about a half mile until I left. This mother seemed more solicitous than a mother elk would be.

On May 24 two rangers and I chased a calf which was following a cow slowly. When one of the rangers overtook the youngster, the mother, a short distance ahead, turned and showed her defiance by pawing the air. After they ran off we caught up to another cow and calf and both calves dropped in the brush when they were unable to keep going. The mothers peered anxiously at us from the steep slope opposite. After going over the hill one of the cows returned and came within 75 yards as we were departing. Some cows run off more readily than others, often disappearing after a brief show of solicitude. Quite often they return to peer over a hilltop to see if the intruder has gone.

Figure 49: A mother caribou trots slowly so her newborn calf can keep up with her. [McKinley River, May 24, 1939.]

On occasions when wolves have killed a calf I have seen the mother searching the area for it. Once I observed a cow smelling of her calf at least several hours after it had been killed. On one occasion a cow with a calf too young to follow, ran off with the herd, but returned to the calf in 10 minutes.

The calves soon begin to feed on green food so that by the time they are a month old their main food is vegetation. On June 12 the calves were feeding extensively on vegetation. The stomach contents of a calf found dead on June 14, 1939, was well filled with green food including the twig of a willow. Since the bulk of the food of very young calves is vegetation, the weaning would not seem to have much effect on the physiology of the calves. By fall the bodies have become accustomed to being nourished almost entirely by vegetation which, we can assume, furnishes a balanced ration. I do not know how late the calves continue to nurse. A cow killed by O. J. Murie on October 18, 1922, had considerable milk in the udder so that the calves were apparently getting some milk at that time.

Continued >>>

Last Modified: Thurs, Dec 20 2001 10:00:00 pm PDT
http://www.nps.gov/history/history/online_books/fauna5/fauna4d.htm