About Reindeer

What's a reindeer? Is it the same as a caribou?

Reindeer and caribou are the same species but different subspecies. Alaskan reindeer are classified as Rangifer tarandus tarandus while Alaskan caribou are known as Rangifer tarandus granti.

Here's a complete taxonomy chart for Rangifer tarandus:

PhylumChordata (backbone with spinal cord)
Class Mammalia (milk producing)
SubclassUngulata (hooved)
Order Artiodactyla (even-toed)
SuborderRuminantia (true ruminant)
Family Cervidae
Genus Rangifer

As a result of thousands of years of domestication and selective breeding, reindeer and caribou have some distinguishing physical and behavioral characteristics.

Caribou are migratory creatures, traveling long distances to winter pasture and back again for spring calving. They tend to be lean, with long legs well suited to long migrations. When herded or chased, caribou tend to spread out and scatter. Caribou bulls may be larger than reindeer bulls, but females are usually similar in size.

Reindeer are much more sedentary than caribou. While they do exhibit seasonal grazing patterns, their movements remain primarily within a well established home range. Reindeer tend to have a more robust body shape, with shorter legs and a flatter face. When herded, reindeer gather together into a cohesive unit instead of spreading out. It is interesting to note that just one or two caribou in a reindeer herd will cause the entire herd to behave more erratically and scatter.

Rangifer tarandus is the only deer species in which both the males and females grow antlers. Even calves grow antlers during their first year! Antlers, by definition, are shed and re-grown every year. Bulls lose their antlers during the winter, typically around Christmas time. Non-pregnant females will also lose their antlers during the winter. Pregnant females will not drop their antlers until they give birth in the spring. Because animals with antlers are dominant over those without, this adaptation allows pregnant a female to protect her food resources during scarce winter conditions, ensuring adequate nutrition for the continued development of her fetus.

Female reindeer typically reach reproductive maturity as yearlings, though it is possible for a female to become impregnated during the fall of her first year and give birth as a yearling. Females may stay productive for a dozen years or more.

Bulls don't fully exhibit the characteristics of rut until about three years of age. Because they are unable to compete with other bulls prior to this, they rarely successfully breed as very young animals. They are, however, reproductively viable by the time they are yearlings. In the absence of older bulls, they are capable of servicing females, though they are able to maintain only a small harem.

Bulls typically don't live past about 8 years of age. During the rut, they are active in keeping their harem together and they eat very little during this time. When winter arrives, they are in poor condition and must struggle to gain weight during the scarcest time of year. Older bulls often cannot survive the harsh winter once they become weakened by the rut.

Breeding season for reindeer happens during August and September. Gestation lasts for 200-220 days and females will begin to give birth in April, continuing into May. The reproductive cycle of North American caribou is about a month behind that of reindeer.

The birth weight of reindeer calves typically ranges from 6 to 8 kilograms. They grow quickly, and weigh between 65 and 75 kilograms by the time they are yearlings. As adults, females (non pregnant) weigh from 70-90 kilograms while males weigh 90-120 kilograms, depending on the season and whether or not they are castrated.

Adaptations to Life in the Arctic
Reindeer are uniquely adapted to thrive in the harsh environments of the arctic. To learn more, click here to view a fun and educational slideshow.

From season to season
Each season of a reindeer's life is marked by significant physiological and behavioral changes. To learn more, have a look at this seasonal calendar.

History in Alaska
Alaska has been home to reindeer for more than a century. For a detailed acount click here.

The Seward Peninsula
Though reindeer are found throughout western Alaska, the population is concentrated in free ranging herds on the Seward Peninsula. Read more here.

Reindeer in the circumpolar north
Check back soon for more information about reindeer throughout the north.

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Contact Information
Reindeer Research Program
Page Last Modified: 05/15/15 1:29 pm by: dsblodgett@alaska.edu