During the rut, in late September and early
October, bulls become unpredictable and dangerous. At this time, both sexes call
to each other. Cows emit a wail-like bawl while bulls respond with a heavy
grunt-like noise that can be heard up to half a kilometer away. Moose often form
temporary associations ranging in size from male and female pairs to several
adults. Bulls are polygamous and may seek out more than one cow to breed with.
The cows are receptive for 7 to 12 days, but experience true oestrus for only
about 24 hours. If breeding does not take place immediately, successive oestrus
cycles may occur at 20 to 30 day intervals.Serious
fighting between bulls erupts occasionally. It often starts by one
pushing the antlers of the other for six to eight steps, then the other
will plant its feet and push back. Such activity may be interspersed
with jerky grazing motions, and continue for hours. Serious fighting may
result in death or locking of the antlers. If the animals cannot break
loose, they eventually die of exhaustion and starvation.
In late May or early June, the cow moose seeks out a secluded location, often on
an island or peninsula, to give birth. A single calf is usually produced by
young cows, while mature animals often have twins, and triplets occasionally
occur. The calf or calves from the previous year may still be with the cow when
the young are born, but she will reject them in order to be alone with her new
calves. Cows give birth lying down and often nurse while still on the ground.
The cow thoroughly licks the calf at birth and this becomes a ritual activity,
reinforcing the maternal bond.
The new calf is totally helpless and is kept isolated and carefully guarded for
a few days. If the calf is frightened, it will fall to the ground and lie
absolutely silent until the danger passes. The protective instincts of the cow
are strong, and she will often charge at perceived threats such as a bull moose,
humans, and bears, by rushing forward and striking at them with both front feet.
A newborn calf has a reddish-brown coat, long
legs and ears, and a short muzzle. By the time it is a week old, it can run
faster than a man and swim short distances. Young calves are frisky and playful,
and do not develop a fear of humans until they are older. At about two months
they begin to lose their baby appearance, and the characteristic long muzzle
begins to develop. The pelage changes to a longer, dark grey-brown coat as
The moose grows more quickly than most animals as a result of the high fat
content of the mother's milk. A calf weighs an average of 14 kg at birth and
gains 0.05 to 0.09 kg daily in its first month. By the second month it starts
gaining over 1 kg per day. By six months of age the moose can weigh nearly 200 kg.
The rapid weight gain is facilitated by nursing which continues until fall, and
foraging which begins at two weeks of age.