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Muskox
Reproduction
Throughout
most of the year, muskoxen are placid animals. But towards the end of
summer, the arctic stillness is broken by the crash of muskox horns as the
bulls challenge each other for supremacy of the herds.
A lead bull must continuously defend his position. Skirmishes may occur at
any time of year, but when the rut begins, fighting between bulls becomes
serious and prolonged. Normally a mere threat from a dominant bull is
sufficient to frighten away an intruder, but at the height of the rut,
threats give way to noisy and dramatic battles with bulls charging each
other and meeting head on with resounding thuds. The impact of the great
blows is absorbed by the thickness of the horns and skull, and the weaker
contender usually moves off before much damage is done. During the
battles, cows and immature animals pay little attention and continue
grazing placidly.
Rutting reaches its
peak in late summer and courtship continues through September. As the
dominant bull establishes his position, the herds change to harem-like
groups composed of one adult bull with several cows, calves and sub-adult
bulls. Defeated bulls either group together or become solitary. Young
bulls may aggressively try to rejoin herds, while older ones seem content
to wander about the tundra alone, feeding and sleeping.
The period of gestation
for muskoxen is 8 to 9 months. Calves are born at similar times throughout
the NWT despite differing temperatures on the most northerly and most
southerly ranges. Calving has been observed from the first week in April
until mid-May. Temperatures are still well below freezing and the snow
cover is deepest when the calves are born, but unless conditions of
extraordinary wind or freezing rain occur, new-born calves are well able
to survive the harsh conditions.
Muskox calves can stand upright and suckle within a few minutes of birth.
For the first few weeks, they remain close to their mothers and within the
safety of the herd. Lone cows and calves have been observed far from a
herd, but this must be unusual behaviour, for without herd protection, a
cow and her new-born calf have little hope of surviving a wolf or grizzly
bear attack.
As the calf grows, it moves around the herd's feeding area and plays with
other young animals, but at any sign of danger it rushes to its mother,
sometimes hiding itself completely under her flowing skirts.
Muskox
calves are almost pig-like in appearance. They are born with short
woolly coats, which begin shedding in July. By September, the small muskox
is a miniature replica of its elders with new underhair and longer
over-hair. During the third winter, the full coat or pelage of an adult
muskox develops.
The calf may stay with its mother until well into its first year. In
productive areas, the females produce calves in successive years and
weaning probably occurs in late fall or early winter. In less productive
areas, such as the High Arctic, the female may only breed in alternate
years and the yearling may continue to nurse until it is 15 to 18 months
old. Prolonged lactation provides extra nourishment during harsh winter
months when food is difficult to obtain.
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