Muskox

## Description

Muskoxen are Arctic hoofed mammals, noted for their thick coat and for the strong odor emitted during the seasonal rut by males, from which their name derives. Both male and female muskoxen have long, curved horns. They have a thick coat, large head, and small tail that is often concealed under a layer of fur. Their coat, a mix of black, grey, and brown, includes long guard hairs that almost reach the ground.

## Distribution

Muskoxen live in Greenland and the Canadian Arctic of the Northwest Territories and Nunavut. They inhabit tundra; during the summer, muskoxen live in wet areas, such as river valleys, moving to higher elevations in the winter to avoid deep snow.

## Behavior

Muskoxen are diurnal and social animals. They live in herds of 12-24 individuals in the winter and 8-20 in the summer. They do not hold territories, but they do mark their trails with preorbital glands. Male and female muskoxen both have separate age-based hierarchies, with mature oxen being dominant over juveniles. Dominant oxen tend to get access to the best resources and will displace subordinates from patches of grass during the winter. Muskox bulls assert their dominance in many different ways. One is a "rush and butt", in which a dominant bull rushes a subordinate from the side with its horns, and will warn the subordinate so it can have a chance to get away. Bulls will also roar, swing their heads, and paw the ground. Dominant bulls sometimes treat subordinate bulls like cows. A dominant bull will casually kick a subordinate with its foreleg, something they do to cows during mating. A subordinate bull can change its status by charging a dominant bull. Muskoxen have a distinctive defensive behavior: when the herd is threatened, the bulls and cows will face outward to form a stationary ring or semicircle around the calves. The bulls are usually the front line for defense against predators with the cows and juveniles gathering close to them. Bulls determine the defensive formation during rutting, while the cows decide the rest of the year.

## Diet

Muskoxen have a herbivorous (graminivorous, folivorous) diet. They eat grasses, Arctic willows, woody plants, lichens, and mosses. When food is abundant, they prefer succulent and nutritious grasses in an area. Willows are the most commonly eaten plants in the winter.

## Reproduction

Muskoxen exhibit a polygynous mating system in which one male mates with multiple females in a single breeding season. The mating (or "rutting") season of the muskoxen begins in late June or early July. During this time, dominant bulls will fight others out of the herds and establish harems of usually 6 or 7 cows and their offspring. Fighting bulls will first rub their preorbital glands against their legs while bellowing loudly and then display their horns. The bulls then back up 20 meters, lower their heads, charge into each other, and will keep doing so until one bull gives up. Subordinate and elderly bulls will leave the herds to form bachelor groups or become solitary. However, when danger is present, the outside bulls can return to the herd for protection. While the bulls are more aggressive during the rutting season and make the decisions in the groups, the females take charge during gestation. Pregnant females are aggressive and decide what distance the herd travels in a day and where they will bed for the night. The herds move more frequently when cows are lactating, to allow them to get enough food to nurse their offspring. Cows have an 8-9 month gestation period after which they usually give birth to a single calf. Cows do not reproduce every year. Calves are born precocial and are able to keep up with the herd within just a few hours after birth. The young are welcomed into the herd and nursed for the first 2 months. After that, they begin eating vegetation and nurse only occasionally. Cows communicate with their calves through braying and the calf's bond with its mother weakens after two years. Young females become reproductively mature at 1 to 4 years of age, while males are ready to breed when they are 3 to 4 years old.

## Population

### Threats

There are no major threats facing Muskoxen at present. Historically, this species declined because of overhunting, but the population recovered due to the enforcement of hunting regulations. In Greenland, there are no major threats, although populations are often small in size and scattered, which makes them vulnerable to local fluctuations in climate. Most populations are within national parks, where they are protected from hunting. Muskoxen occur in four of Greenland's protected areas, with indigenous populations in Northeast Greenland National Park, and three introduced populations in Arnangarnup Qoorua Nature Reserve, and Kangerlussuaq and Maniitsoq Caribou Reserves. Within these areas, muskoxen receive full protection.

### Number

According to the IUCN Red List, the total population size of the Muskox is 133,914-136,914 mature individuals. There are estimated populations of the species in the following areas: Canada: Northwest Territories - 75,400 individuals, Nunavut - 45,300 individuals, northern Quebec, Le Henaff and Crete - 290 individuals; Alaska: Nunivak Island - 609 individuals, Nelson Island - 318 individuals, Seward Peninsula - 2050 individuals, northwest Alaska - 369 individuals, northeast Alaska - 268 individuals; Greenland - 9,500 to 12,500 individuals. Currently, Muskoxen are classified as Least Concern (LC) on the IUCN Red List and their numbers today are stable.

### Ecological niche

Muskoxen are important predators of plants in their native landscapes and most likely help to disperse seeds as they graze. They are also an important food source for arctic scavengers such as Arctic wolves, Polar bears, and Brown bears.

## Domestication

Muskoxen are occasionally domesticated for wool, meat, and milk. Their wool, qiviut, is highly prized for its softness, length, and insulation value.