Barren-ground Caribou Fact Sheet
The scientific name for barren-ground caribou is Rangifer tarandus groenlandicus. Rangifere is an old French
word that means “reindeer, an animal of the north country.
What do they look like?
Barren-ground caribou are medium-sized members of the deer family, with
- cinnamon brown coats (for most of the year),
- white on their necks, bellies, and under their tails, and
- bands of white hairs around their legs just above their hooves (they're called socks).
Their faces are darker brown than the rest of their bodies and they have creamy white snouts. Both males and females have antlers. [Caribou are the only species of deer in which the females have antlers as well as the males. Every year caribou shed their old antlers and grow new ones. While the antlers are growing they have a fuzzy covering called "velvet." The velvet has blood vessels that carry nutrients to the antlers so they can grow.]
Where do they live?
In Canada, barren-ground caribou range over the taiga forests and tundra of the Northwest Territories' mainland, and Southampton, Coats and Baffin Islands.
Canada has five main herds of barren-ground caribou. There are some smaller herds too. Biologists aren't sure exactly how many barren-ground caribou there are, but estimate between 900,000 and 1,300,000!
What kind of habitat do they live in?
Most barren-ground caribou have different summer and winter homes that they migrate between. Summer is spent in the treeless Arctic tundra, while winters are spent in the coniferous forest, also called "boreal forest" or "taiga.”
How have they adapted to their habitats?
Caribou have many adaptations for living in a cold climate.
- Their coats change with the seasons: In summer, they have short brown coats. In fall, long white-tipped hairs grow out over top of the summer coats. The hairs in this second coat are hollow. Air trapped inside of these hollow hairs acts like a thick blanket, keeping the caribou warm.
- Their ears and snouts have lots of thick, warm fur.
- Their hooves (feet) change with the seasons: Caribou have very large hooves that are wider than they are long. In winter, the soft pad in the middle of their hooves gets smaller. The hard, sharp edge around the outside grows. The sharp edges are good for walking on snow and ice and for digging through snow to reach food. Hair grows between and over their feet. It keeps their feet warm and protects them from being cut on hard snow and ice. In summer, the hard outside edges get smaller. The soft pads in the middle grow wider. This helps them walk on the soft boggy tundra.
What do they eat?
The main food in a caribou's diet is lichen. No other large mammal can eat lichen. Caribou have special bacteria in their stomachs to help digest chemicals found in lichen. Being able to eat lichen is one of the things that make caribou successful at living in the far north.
Caribou also eat sedges, grasses, other green plants and will nibble on shrubs such as willow and birch. They even gnaw on shed antlers to get nutrients from them!
What do barren-ground caribou do throughout the year
In one year a caribou can travel as far as 4,400 km. The temperature and amount of snow tell caribou when it is time to migrate. Every year each herd of barren-ground caribou follows the same pattern.
Snow plays a big role in a caribou's life. It affects how easily they find food and how they move around.
Winter (November to March)
Most barren-ground caribou spend the winter in the northern boreal forest, also called "taiga.” The forest protects them from the snow and cold. Male and female caribou live in different groups for the winter. Calves stay with their mothers near the edge of the forest, or "tree line."
Only female caribou have antlers over the winter. [Hmmm, what does that tell you about Santa's reindeers?]
In winter, caribou eat more lichen than at any other time of year. The lichen is buried under snow. To feed, caribou use their sharp-edged hooves to dig craters in the snow. Digging, or pawing, takes a lot of energy, so a caribou must be sure there is something to eat before it starts to dig. This is when a caribou's excellent sense of smell comes in handy! Caribous can smell food more than 70 cm under the snow! A caribou sniffs the air at the top of the snow or shoves its snout into the snow and sniffs. If the caribou doesn’t smell any food, it takes two or three steps and tries again. To get enough to eat, a caribou does this hundreds of times each day!
Winters are long and cold. From December to March the air temperature is far below -20°C. There is very little precipitation during the winter.
Spring Migration and Calving Grounds
At the end of March and beginning of April small groups of caribou come together
at the edge of the forest. Spring migration north to the calving grounds on
the Arctic tundra starts. Thousands of caribou travel in lines that are many
kilometres long.
Pregnant females lead the way. They need to get to the calving grounds on time! Calving grounds are usually found in high, rocky areas. The temperature at this time of year is still near freezing. Most of the ground is still snow-covered. Very few plants have started to grow.
When females get to the calving grounds they go off on their own to have their babies. Calves are usually born in the first two weeks of June. A few minutes after a calf is born it can stand up. About one week after having their calves, females shed their antlers.
Summer (July to mid-September)
Females and their calves slowly start to move back toward their winter home.
They eventually meet up with the male caribou, which are still coming from the
wintering grounds, and form herds of tens of thousands of caribou!
The beginning of summer brings huge numbers of biting insects, such as mosquitoes, warble flies, black flies and nose bot flies. The nose bot flies are especially gross and bothersome. The flies hatch in the caribou's nose and then move into the caribou's throat making it difficult to breathe.
Caribou try to avoid insects in three main ways:
- Run away: Caribou sometimes run for many kilometres at a time to escape insects. Running uses up lots of energy and if they are running they can't eat. Caribou can lose a lot of weight this way.
- Move to high windy places.
- Get close together in large groups: More caribou means fewer bugs (and bites)
for each caribou.
Summer is warm but short. It is also the wettest time of the year in the Arctic tundra. Plants on the tundra have to grow really fast in the summer because it doesn't stay warm for long.
In August and September the tundra is in full bloom. There are lots of plants and most of the pesky insects are gone. The caribou start to spread out from their large groups and EAT! They feed on sedges, grasses, mosses and of course, lichens.
A lot of the energy from the food they eat is stored as fat. They need it for the migration back to the boreal forest.
Fall Migration and Mating Season (September and October)
Fall migration usually starts with the first big snowfall. When the caribou get close to the boreal forest they form large herds again. October is mating time. At this time of year, male caribou look their best, with
- shiny coats,
- thick, white manes under their necks, which swell,
- sporty white stripes across their lower bodies, and
- smooth antlers, polished by being rubbed against trees.
For two to three weeks the males have small fights or "sparring matches" over females. The female caribou watch. The fights get bigger and then males chase after females.
When mating is over it is wintertime. The caribou have finished migrating back to their winter home. By the time they get there, there is usually already 25 cm of snow.
The adult male caribou shed their antlers. The males and females break up into separate groups.
The barren-ground caribou are ready for another quiet winter digging for lichen in the boreal forest.