Chapter 3: Muskoxen in North America

In what kind of a climate, and on what kind of a plant-cover is the muskox living in the tundra and polar desert of northern Canada? What have scientists now found out about this?

J. S. Tener, with the Canadian Wildlife Service, reports in his book, Muskoxen (1965): "Especially important to living things is the duration of freezing temperatures. In high latitudes, frost can occur any day throughout the year. And the length of the plant growing season, defined as days with temperatures of 42°F or greater, is 40 days or less. The growing season on the mainland is 80 to 100 days. ... Porsild has pointed out, that the mean annual precipitation is so low, that, were it not for water, which results from summer melting of surface permafrost, large areas in the Arctic islands would be entirely without vascular plants.

"The melt season on the Arctic mainland begins in the first half of May and snow is usually gone, except for drifted areas, by the middle of June. On the islands, melting usually starts early in June and is over in about two weeks. ... Smaller lakes are free of ice early in July on the mainland, but larger lakes may retain some ice until August. However, the larger lakes, such as Lake Hazen on northern Ellesmere Island, may be partly ice-covered throughout the summer months.

"The northernmost region of muskox occurrence in Canada, northern Ellesmere Island, receives 24 hours of sunlight daily from about April 10 to the end of August each year. No sunlight is received from about October 22 to March 1. During the depths of winter, then, high Arctic animals, including muskoxen, must carry on their daily functions in darkness or near darkness." Tener, J. S. (1965:18-20).

"The range study site on Fosheim Peninsula, Ellesmere Island, extended across two valleys and the plain between them. The site was immediately north of the Eureka weather station (80°09´N, 86°00´W).

"The Lake Hazen range sites were on the north shore of the lake, opposite Johns Island (81°54´N, 70°50´W). The summer range studies were done on two adjacent areas on the lower slope of Omingmak Mountain." Tener, J. S. (1965:26, 27) 

Fosheim Peninsula Ranges

"The most outstanding characteristic of that range was the very large proportion of non-vegetated ground. Gravel, rock, silt, and clay together constituted 85.5 per cent of the points, sampled, and vegetative cover only 14.5 per cent. Stream beds and small rock outcrops accounted for part of the unproductive area, and clay hillsides and hilltops, dry and eroding, were frequently barren. On the whole, however, the percentage of vegetative cover was low, because of scattered growth of plants under unfavourable climatic and soil conditions, not because of large barren areas. Of particular significance are the percentages of willow and grasses, available for muskox food. The availability of those plants, along with sedges, is considered to be a prime factor in the abundance of muskoxen on the peninsula." (1965:28).

Muskox range on Fosheim Peninsula, Ellesmere Island.

Plant species:

Poa sp. covered 0.48 % of area

Dryas integrifolia covered 3.5 % of area

Salix arctic covered 2.25 % of area

Carex rupestris covered 0.18 % of area

Alopecurus alpinus covered 1.16 % of area. – J. S. Tener (1965:29) Table 5.

Thelon Game Sanctuary, Northwest Territories

Thelon Game Sanctuary, at 64°17´N, 102°41´W., at the northern treeline.

Dry weight production of selected muskox food species at Thelon Game Sanctuary

Summer range 1: 393.40 kg/acre (97.21 g/m²)

Winter range 1: 288.13 kg/acre (71.20 g/m²)

Winter range 2: 468.56 kg/acre (115.78 g/m²). - From: Tener, J. S. (1965:33) Table 8

Chemical analyses of muskox food plants

"Eight species of plants were collected in April 1956 in the northeast portion (64°29´N, 102°08´W) of the Thelon Game Sanctuary during a winter study of muskoxen. Two lichen species also were collected, as it was observed, that the animals ate the lichens, when they were entangled in the prostrate branches of shrubs.

"All the species analysed except Agropyron sp. were being consumed by muskoxen under observation. The protein value of each species varied between 2.76 per cent for an Agropyron sample and 7.22 per cent for the moss, Rhytidium rugosum (Hedw.) Kindb. The important muskox foods, birch, crowberry, Labrador tea, bilberry, and cowberry gave protein values between 4.5 and 6.00 per cent."

Chemical analyses of muskox food plants. Thelon Game Sanctuary, winter range.

J. S. Tener (1965:32, 33) Table 9. Date collected, April 4-22, 1956:

Protein (N x 6.25): 3.76, 7.22, 3.10, 2.76, 5.95, 4.71, 4.38, 5.93, 5.16, 5.52:

Average: 3.795% CP (dry wt).

Lake Hazen, Plant Production

Plant production at Lake Hazen was determined for two species only, willow (Salix arctica Pall.) and sedge (Carex stans Drej.), and is shown in Table 14.

Table 14. Dry weight production of selected muskox food species, Lake Hazen, Ellesmere Island. Production in kilograms per acre

Summer range Winter range 1

Carex stans Drej. 21.85 (5.40 g/m²)

Salix arctica Pall. 60.30 (14.90 g/m²) 23.80 (5.88 g/m²)

Total 60.30 (14.90 g/m²) 45.65 (11.28 g/m²)

The percentage of bare ground on the two Thelon summer ranges averaged 62.7 per cent, compared with 67.3 per cent on Lake Hazen summer ranges and 85.5 percent on Fosheim Peninsula. Tener, J. S. (1965:40, 42)

"Dry-weight production of selected food species per acre was much higher in the Thelon region, although direct comparisons are difficult, because of differences in genera and species of plants in the high and low arctic. The total annual production of all food species was about seven times as large per acre in the Thelon, as at Lake Hazen. Winter-range food production was from 6 to 10 times higher on the Thelon ranges studied, than at Lake Hazen. (1 acre = 4.0468 km²).

"Adult beef cattle require something over two pounds of dry food matter per 100 pounds (45.36 kg) of animal per day for maintenance, according to data provided by the Committee on Animal Nutrition of the National Research Council of the United States (1950). While precise muskox maintenance requirements are unknown, assuming the quality of food is equal, an 800-pound (363 kg) muskox would require about 17 pounds or 7.7 kilograms of dry, good quality forage per day.

"Based on food production alone, one acre (4.047 km²) of the Thelon summer range studied, would support, on the above basis, 1.7 adult 800-pound (363 kg) muskoxen per month. The two winter ranges in the sanctuary would support 1.2 and 2.3 muskoxen per acre per month.

"One acre (4.047 km²) of summer range and one acre of winter range at Lake Hazen would support 0.25 and 0.19 muskoxen per month respectively. In other words, an adult 800-pound (363 kg) muskox at Lake Hazen would need at least four acres (16.19 km²) of summer range, to obtain sufficient food for one month and at least five acres of winter range.

"The data, though scanty, thus suggest, that summer ranges in the Thelon Game Sanctuary may support up to about seven times as many muskoxen, as summer ranges at Lake Hazen, and up to 11 times as many muskoxen on the winter ranges.

"Winter range sites of the Thelon Game Sanctuary compare favourably in production of annual forage with Jasper and Banff Parks and southern prairie ranges. The Lake Hazen range, however, produced about one-third to one-fourteenth of the forage of the park and prairie ranges. Evaluations of the production of herbivorous animals in high Arctic areas must be predicted on the low amounts of forage, available for all herbivorous species." J. S. Tener (1965:43).

Thelon Game Sanctuary 393.40 kg per acre (97.21 g/m²) aboveground dry matter per year.

Lake Hazen 60.30 kg per acre (14.90 g/m²) aboveground dry matter per year. - Tener, J. S. (1956:44) Table 16.

Feeding behaviour

"The muskox gets its food by wrapping its tongue around such plants as grasses and sedges and tearing off leaves and stems, or by biting off, with its upper lip and lower incisors, the leaves and terminal twigs of short plants, such as the prostrate Arctic willow. On the arctic mainland, where willows may exceed six feet in height, the muskox may strip the leaves and terminal twigs, by wrapping its tongue around the foliage and jerking its head up or down. In the Thelon area, it is not unusual, to first detect the presence of a muskox by the thrashing of a willow bush.

"As a rule, muskoxen do not feed intensively in one spot in summer, even in abundant vegetation. When in willow thickets, the animals move through slowly and may spend several hours, alternately browsing and ruminating. It is unusual for a herd, to remain at one site, feeding on one restricted area, for more than a day. The animals move up and down river systems, along lake shores, or across tundra, browsing and resting, but never remaining in one spot, until all food is fully used up." J. S. Tener (1956:47)

"Winter observations of muskoxen suggest, that a herd may remain for several days feeding in one place, possibly, because a particularly good food source is available. Other herds and individuals, however, do move more frequently, but the rate of movement does not appear to be as rapid as in summer. Perhaps, conservation of energy is achieved in this way, in the season, when energy requirements are high." J. S. Tener (1956:48)

Size

Four bulls of the moschatus subspecies from the Arctic mainland (Table 18) averaged 750 pounds (342 kg), and one wardi specimen from Melville Island weighed 715 pounds (324 kg).

"Those weights are in marked contrast to weights of two moschatus bulls, raised in captivity by John J. Teal at Huntington Center, Vermont. At 51 months of age, one bull weighed 1135 pounds (515 kg), the other 1450 pounds (658 kg). At six years of age, the latter was estimated to weigh 1400 pounds (635 kg). As Teal remarked, such weights are probably the result of excellent nutrition, as well as being representative of the larger race. Two adult cows of Teal’s, one seven years of age and the other six, weighed 620 pounds (281 kg) and 655 pounds (297 kg) respectively." J. S. Tener (1965:53).

Calving

"Calves, born in late April, may encounter temperatures as low as –30°F (-34.4°C), or in early May, -20°F (-28.9°C). For example, on April 25, 1951, a calf, a few hours old, was found on the south shore of Slidre Fiord, Fosheim Peninsula. The minimum temperature that morning was –27°F (-32.8°C). On April 22, 1956, the minimum temperature was –16°F (-26.7°C) in the Thelon Game Sanctuary, where a calf, less than a day old, was observed. Calves, born in May, usually encounter temperatures above zero (Fahrenheit) (-17.8°C), but below freezing.

"It is likely, that a selective balance has been achieved between the arrival of calves under tolerable winter conditions and the ability of the young animals, to achieve maximum growth benefits from new forage during the short summer season. New vegetation appears by mid-June even in the high Arctic regions and calves, which begin grazing within a week of birth, are able to utilize it.

"Calves commence suckling the cow within a few minutes of birth. Within a week, they start to eat the dry vegetation, on which their parents are feeding. A calf, collected May 11, 1960, for example, and estimated to be four days old, was found to have grass fragments in its stomach." Tener, J. S. (1965:75, 76)

"Previous sections of this paper have discussed the sparseness of vegetation on muskox ranges and have examined muskox feeding habits. While the species prefers certain plants, such as willows and grasses, it will also eat sedges, forbs (= plants with large leaves), and woody species. Otherwise, it is doubtful, if muskoxen could survive in the Arctic, where annual production of most food species is so low.

"The present study has indicated other physiological adaptations to the less nutritious and less abundant food of winter. The marked increase of liver weights, as the summer season progresses, suggests, that food, stored in that organ, may be an important source of energy during periods of food shortage in winter months. The production of milk with good fat, protein, and lactose content would assist calves, to cope with low temperatures and dried forage, until spring vegetation appeared. Prolonged lactation by the muskox, which may continue until the calf is at least 15 months of age and perhaps longer, would provide supplemental food to the calf during periods of environmental stress." J.S. Tener (1965:105)

"Muskoxen may spend one to several days feeding in a restricted region, but destruction of forage species has not been observed, to take place, because of their habit, of changing feeding sites frequently and because the numbers of muskoxen in each herd are small. … The quality and availability of food are two of the most important factors, influencing the abundance of ungulates. ... It would appear that, while muskoxen are able to live in the Arctic, their environment is marginal, rather than optimum, because of nutritional limitations. The barely adequate nutritive value of winter food species indicate, that muskox populations in northern regions will not reach densities, which will support intensive utilization. ... Food is so scarce in the high Arctic regions, that muskox numbers will always be low, unless favourable climatic changes occur." J. S. Tener (1956:108, 111, 116)

Three adult bulls in defence formation, Fosheim Peninsula, Ellesmere Island. Shedding of inner hair is just beginning. The thin snow cover is typical of most muskox winter ranges. From: J. S. Tener, Muskoxen in Canada 1965, Canadian Wildlife Service.