THINGS YOU SHOULD KNOW ABOOUT REINDEER

The reindeer, also

known as the

caribou in North

America, is a deer

from the Arctic and

Subarctic, including

both resident and

migratory

populations. While

overall widespread

and numerous, some

of i

ts subspecies are

rare and one

has

already gone extinct.

Reindeer vary

considerably in color

and size. Both sexes

grow antlers, though

they are typically

larger in males.

There are a few

populations where

females lack antlers

completely.

Even far outside its range, the reindeer is well known due to the myth, probably originating in early 19th century America,

in which Santa Claus's sleigh is pulled by flying reindeer, a popular secular element of Christmas.

The reindeer is a widespread an

d numerous species in the northern Holarctic. In North America, it was found in Canada,

Alaska, and the northern conterminous USA from Washington to Maine. Wild reindeer have disappeared from many

areas. Large populations of wild reindeer are still found i

n Norway, Finland, Siberia, Greenland, Alaska, and Canada.

Size

:

The females usually measure 162

–

205 cm (64

–

81 in) in length and weigh 79

–

120 kg (170

–

260 lb). The males (or "bulls")

are typically larger (although the extent to which varies in the differen

t subspecies), measuring 180

–

214 cm (71

–

84 in) in

length and usually weighing 92

–

210 kg (200

–

460 lb), though exceptionally large males have weighed as much as 318 kg

(700 lb). Shoulder height typically measure from 85 to 150 cm (33 to 59 in), and the tail

is 14 to 20 cm (5.5 to 7.9 in) long.

The subspecies R. t. platyrhynchus from Svalbard

Island

is very small compared to other subspecies.

Antlers

:

In most populations both sexes grow antlers, which (in the Scandinavian variety) for old males fall off in De

cember, for

young males in the early spring, and for females in the summer. The antlers typically have two separate groups of points,

a lower and upper. There is considerable subspecific variation in the size of the antlers (e.g., rather small and spindly

in

the northernmost subspecies), but in some subspecies the bull reindeer's antlers are the second largest of any extant

deer, after the moose, and can range up to 100 cm (39 in) in width and 135 cm (53 in) in beam length. They have the

largest antlers rel

ative to body size among deer.

Nose and Hooves

:

Reindeer have specialized noses featuring nasal turbinate bones that dramatically increase the surface area within the

nostrils. Incoming cold air is warmed by the animal's body heat before entering the lung

s, and water is condensed from

the expired air and captured before the deer's breath is exhaled, used to moisten dry incoming air and possibly absorbed

into the blood through the mucous membranes.

Reindeer hooves adapt to the season: in the summer, when t

he tundra is soft and wet, the footpads become sponge

-

like

and provide extra traction. In the winter, the pads shrink and tighten, exposing the rim of the hoof, which cuts into the ice

and crusted snow to keep it from slipping. This also enables them to di

g down (an activity known as "cratering") through

the snow to their favorite food, a lichen known as reindeer moss. The knees of many species of reindeer are adapted to

produce a clicking sound as they walk.

Vision

:

Reindeer are thought to be the only mam

mals that can see ultraviolet light. A study conducted by researchers from the

University College London in 2011 revealed that reindeer can see light with wavelengths as low as 320 nm, considerably

below the human threshold of 400 nm. It is thought that th

is ability helps them to survive in the Arctic, because many

objects that blend into the landscape in normally visible light, such as urine and fur, produce sharp contrasts in ultraviole

t.

Diet

:

Reindeer are ruminants, having a four

-

chambered stomach. The

y mainly eat lichens in winter, especially reindeer moss.

However, they also eat the leaves of willows and birches, as well as sedges and grasses. There is some evide

nce to

suggest that on occasion

they will also feed on lemmings, arctic char, and bird eg

gs.

Reproduction

:

Mating occurs from late September to early November. Males battle for access to females. Two males will lock each

other's antlers together and try to push each other away. The most dominant males can collect as many as 15

-

20 females

to mate with. A male wi

ll stop eating during this time and lose much of its body reserves. Calves may be born the following

May or June. After 45 days, the calves are able to graze and forage but continue suckling until the following autumn and

become independent from their moth

ers.

Migration

:

Some populations of the North American caribou migrate the furthest of any terrestrial mammal, travelling up to 5,000 km

(3,100 mi) a year, and covering 1,000,000 km2 (390,000 sq mi). Other populations (e.g., in Europe) have a shorter

migr

ation, and some, for example the subspecies R. t. pearsoni and R. t. platyrhynchus (both restricted to islands), are

residents that only make local movements.

Normally travelling about 19

–

55 km (12

–

34 mi) a day while migrating, the caribou can run at spee

ds of 60

–

80 km/h (37

–

50 mph). During the spring migration smaller herds will group together to form larger herds of 50,000 to 500,000 animals,

but during autumn migrations the groups become smaller,

and the reindeer begin to mate.

During the winter, reinde

er travel to forested areas to forage under the snow. By spring, groups leave their winter grounds

to go to the calving grounds. A reindeer can swim easily and quickly, normally at 6.5 km/h (4.0 mph), but if necessary at

10 km/h (6.2 mph) and migrating her

ds will not hesitate to swim across a large lake or broad river.

Predators

:

A variety of predators prey heavily on reindeer. Golden Eagles prey on calves and are the most prolific hunter on calving

grounds. Wolverine will take newborn calves or birthing c

ows, as well as

(less commonly) infirm adults.

Brown Bears and polar bears prey on reindeer of all ages, but like the wolverines they are most likely to attack weaker

animals, such as calves and sick deer.

The Gray Wolf is the most effective natural preda

tor of adult reindeer, especially during the winter. As carrion, caribou are

fed on by foxes, ravens and hawks.

Blood

-

sucking insects, such as black flies and mosquitoes, are a plague to reindeer during the summer and can cause

enough stress to inhibit fe

eding and calving

behav

iors

.