|
 In addition
to hunting, the three major
determinants of moose survival
are predators, snow conditions
and disease.
The timber wolf is the most
serious predator of moose in
Alaska. They often detect moose by
scent. When the moose population
is thriving, wolves act as a
culling agent for old or
diseased animals and weakened
calves. When the moose becomes
aware of danger, it can either
stand and fight or run. A single
wolf or a small group of wolves
are no match for a healthy
moose, which uses all four
powerful legs to strike an
opponent. However, a group of
more than four or five wolves
can pull down and kill a large
moose. If the moose decides to
run, wolves give chase and
attempt to slow the moose by
grabbing it by the nose, rump,
or hocks. In this case, an
organized attack by a large
group of hungry wolves is often
fatal for the moose.
In the Yukon and Alaska, calf
predation by grizzly and black
bears has been shown to have a
major effect on the size of
moose populations. This may also
be the case in Alaska, but to
date no data are available.
Predation and snow conditions
are interrelated factors that
can have a significant effect on
moose numbers. When snow is deep
and moose ''yard'' together,
they are more accessible in
greater numbers to wolves. Moose
have relatively long legs that
allow them travel through deep
snow easier than most other
ungulates. However, snow depth
of over 90 cm greatly hinders
their movements and their
foraging ability is seriously
restricted. Crusted snow can
also be detrimental to moose in
that it can pierce the skin on
the forelegs and crack the
hooves, making it vulnerable to
predation.
Moose are susceptible to a
variety of parasites.
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Tapeworms that cause cysts do
not directly influence moose
mortality, but instead hinder
their response to stress. Three
types of tapeworms that can be
found in moose in Alaska are
liver tapeworm cysts (Taenia
hydatigena), hydatid disease in
the lungs (Echinococcus
granulosus), and muscle tapeworm
cysts (Taenia krabbei). |
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"Moose disease" is caused by a
parasitic roundworm (P. tenuis)
carried and transmitted by
white-tailed deer. Infestation
in moose can damage the central
nervous system and ultimately
invade the brain, usually
causing death. The symptoms of
the disease include walking in
circles, bumping into objects,
losing fear of man, and general
lack of co-ordination. "Moose
disease" is not found in
Alaska
and Western Canada at this time. |
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Ticks (Demacentor albipictus)
feed on the blood of
the moose, severely
weakening the
animals and causing
hair loss which then
increases heat loss. |
In some places a significant
number of moose are killed
through collisions with motor
vehicles. This has a significant
impact on the moose population
each year in Alaska because of
moose accidents with motor
vehicles. Other minor
causes of mortality to moose are
drowning, falls, and wounds
caused during rutting combat. |
