 NORTH
AMERICAN MOOSE
All North American moose seem to
have originated from Siberia.
However, views of when they
arrived in the taiga around the
Great Lakes differ. The first
invasion probably did not occur
before the end of the last
glaciation, 10,000 to 14,000
years ago.
Peterson (1955) hypothesized
that moose reached the taiga
before development of the
Wisconsinian ice shield.
Peterson speculated that these
four distince refuges of moose
became the centers of origin of
the four modern subspecies of
moose in North America. The
three southern races were
separated by extensive
grasslands, whereas the northern
race was separated by the
extensive ice shield itself.
Other hypothesizes exist
discussing northern herds moving
south and vise versa causing
changes with the existing groups
of moose.
During the mid-Wisconsinian
glacial period, sea ice in the
southern Bering Sea possibly
provided a migration corridor
for taiga moose from the Far
East over the Aleutian chain
without intermixing with the
more northern forest/tundra
moose.
In English, the Latin name Alces
means “elk”, a term erroneously
used by the first American
settlers for the North American
Elk (Cervus elaphus) or
“wapiti.” Historically, in
Eurasia, the moose is referred
to as the elk, and red deer has
been synonymous with wapiti.
Presently in Eurasia, the terms
elk and moose are synonymous.
The present moose Alces alces
appeared in Europe about 0.5
million years ago (Flerov 1931,
1950, Vereshchagin, 1967). The
accepted genus Alces was
originally named Cervus by
Linnaeus (1758), but also
included Alce (Hamilton-Smith
1827) and Paralces (Allen 1902).
The systematics of North
American moose are not
definitive and some changes may
occur. Presently, the following
subspecies are accepted.
Alaskan/
Yukon or Tundra Moose
Shira’s or
Yellowstone Moose
Eastern or
Taiga Moose
Northwestern Moose
Moose
Antlers
Calcium:
Hydroxyapatite is the main
mineral in antlers and is
responsible for antler strength.
Mineralization proceeds slowly
during the first two-thirds of
the antler growth. Both the
antler cortex and core remain
relatively porous and fragile.
During the last third of growth,
mineralization is dynamic.
Toward the end of the
mineralization phase, growth
stops and the antlers become
pointed.
Mineralization:
Generally, with maturity, the
density and specific gravity of
antlers decline. Miller et al.
(1985) suggested that only small
antlers (spikes and forks) are
nearly totally compact, thus are
not strong enough to resist the
torque imposed on their
flexibility during fights. In
contrast, palmated antlers
develop not only large surfaces,
but also a spongy core that
strengthens the antler and
absorbs the impact of blows and
twists during fighting.
The
Pedicle and Antler Death:
The pedicle (antler base) is
covered by a skin. The skin rim
seals the potential cleft
between the bone and the skin of
the pedicle. It protects against
infect ion and prepares itself
for future proliferation of the
bone-forming tissue after the
antler sheds. It is at this
location that thick arteries and
veins develop to develop
nutrients to the growing antler
(Rorig 1900, Suttie and Fennessy
1990, Goss et al. 1992).
The circumference of the antler
base grows with age, but remains
identical with the pedicle. Dead
antlers remain connected to the
pedicle as long as the core and
cortex of the pedicle do not
begin to regenerate. Mature
bulls with large antlers
generally cast them in early
winter, and immature bulls with
small antlers generally retain
them until late winter and some
even into spring.
Velvet:
All antler growth and
mineralization develop under the
velvet (Vacek 1955, Goss 1983,
1985, Goss et al. 1992, Bubenik
1993b). According to Vacek
(1954), velvet is the most
sensitive skin among mammals.
The length of the velvet period
in species is age dependent and
may last from 60 to 160 days. In
prime moose it lasts about 140
days.
To keep any tissue alive, oxygen
and nutrients must be supplied
and waste must be removed.
Damage to velvet during
development affects normal
antler growth, and extensive
damage can result in extreme
deformities. During the velvet
stage, bulls are very protective
of their growing antlers when
moving through forest. They have
a great sense of the antlers’
size and thereby avoid injuring
them. The “bump” on the skull
seen occasionally between the
antlers in older bulls is
proliferated bone tissue, the
result of sparing and fighting
during the rut. Ribs and
shoulder blades may lose as much
as 40 percent of their calcium
during the rut process (Banks et
al. 1968b).
Nearly every hormone-producing
tissue and hormone in the body
has an influence on
antlerogenesis. In the adult,
testosterone is important in
direct control of antler growth
cycles (Blauel 1935, 1936,
Wislocki et al. 1947). The
absence or deficiency of
testosterone achieved by
castration or noted in
cryptorchids (males with
un-descended testicles) has a
tremendous effect on
antlerogenesis. Castration
during the hard-antler stage
induces casting within 2 weeks
and new but uncoordinated antler
growth.This sometimes builds
into bizarre features called
freak antlers.
Velveted antlers have been
recorded in both sexes of moose
(Kapherr 1924, Murie 1928,
Skuncke 1949, Seton 1953,
Wisehart 1980, 1990, Hohle and
Lykke 1986).
Prime antlers are carried by
moose aged 5 to 12 years. These
antlers show a great range of
variance in both taiga and
tundra moose (Gasaway et al.
1987). They grow steadily in
size until the bulls’ tenth year
when they reach optimal size and
form. Between the eleventh and
thirteenth years, a plateau in
antler growth seems to occur (Timmermann
1971, Bubenik et al. 1978).
The architecture of the
brow-palms and their points
appear to have behavioral
significance. Brow-points
provide the optimum defence of
the forehead. Most prime bulls
have this characteristic.
Brain Size:
In moose, individual brain size
varies considerably. In taiga
moose of northwestern Ontario,
the brains of 6-month-old calves
are between 19.0 to 26.2 cubic
inches (312 – 430 cm³), and
increases to 22.9 to 32.3 cubic
inches (375 – 530 cm³) in full –
grown adults (Bubenik and
Bellhouse 1980).
Eyes and
Vision: Little is known
of the acuity of vision in
moose, but it is recognized that
moose depend less on sight than
on hearing and smell to detect
activity in their proximity.
Moose must move their eyes to
assess objects at close range.
They can also move their eyes
independent of one another.
Ears and
Hearing: Compared with
humans, moose have very acute
hearing. Both large ears and
possibly the antlers play an
important role in hearing.
Chemical
Reception: As in other
members of the deer family,
chemical communication is of
paramount importance to the
moose. There are three organs
that serve as receptors of
chemical signals – the nose or
rhinarium, the vomeronasal or
jacobson’s organ, and the
tongue. The distance between
moose nostrils is almost as
great as the distance between
human ears.
The moose tongue has the longest
movable part among tongues of
all deer (Hofmann and Nygren
1992). It is not known whether
moose can differentiate between
more than the four basic tastes
of sweet, salty, sour and
bitter, as is known for humans
(Freedman 1993).
Skin:
Moose skin is similar to that of
other deer, particularly
caribou. Skin thickness varies
from 0.53 inch (1.34 cm) on the
withers and 0.09 inch (0.23 cm)
on the legs (Sokolov and
Chernova 1987). The skin is
thickest during winter. The skin
of a mature moose constitutes
7.3 to 7.4 percent of the body
mass.
Hair:
Moose have four types of hair –
guard hair, wool hair or
underfur, eyelashes and
vibrissae.
Guard hairs of varying length
cover the entire body. In
winter, on the moose neck and
torso, they can be about 4
inches (10.2 cm) long. Longer
guard hairs grow over the spine
near the hump and can be 10
inches (25.4 cm) or longer.
Wool hairs also cover the body,
but are absent on the legs and
face. The wooly hairs of the
underfur are twisted and can
reach 1.0 inch (2.54 cm) in
length. They probably only grow
in the summer. The underfur is
the most important insulative
sheet over the body.
The stiff eyelashes, 0.6 to 0.8
inch (1.5 - 2.0 cm) long, and
the vibrissae around them are
sensory organs. They stimulate
the eyelids to close to avoid
injury from foreign objects.
Vibrissae are concentrated
around the eyes and mouth.
Vibrissae around the muzzle
serve the same purpose, in
addition to facilitating search
for underwater plants. The
vibrissae are sparse and about
1.6 to 3.0 inches (4.0 – 7.5 cm)
long (Sokolov 1964, Kheruvimov
1969, Sokolov and Chernova
1987).
Bulls in good condition and
barren cows are the first to
grow both the summer and winter
coats. Lactating cows and
juveniles molt last. As in all
deer, the spring molt is
conspicuous, the annual molt is
hardly noticed.
Bell:
The bell of the moose is a
sexually dimorphic structure
that functions as a visual
communicator. The blood supply
does not always protect the bell
from freezing. Occasionally,
part of a bell may freeze and
fall off. Because of this, bells
are seldom present in older
bulls. In some biologists view
that have studied bells, their
view is that the bell evolved
primarily as a visual cue whose
size and shape may be a
secondary indicator of sex,
relative to age and rank,
especially during the antlerless
period.
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Moose off School Grounds Mor
Are there more
than one species
of Moose in North
America? More>
Find out about
Moose Antlers
More>
What is Velvet?
More>
Do You know how
big my brain is?
How good my
vision is?
How good my
hearing is?
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