The Tundra Biome

Arctic Tundra

• Circles the Arctic Ocean across northern Canada, Alaska, Russia, and Scandinavia
• In summer, the sun never fully sets — providing 24 hours of daylight
• In winter, average temperatures are around -30°F (and can fall much lower) and the sun barely rises above the horizon

Alpine Tundra

• Found on high mountains above the treeline — where it's too cold and windy for trees to grow
• Exists on every continent including the tropics — the Andes, Himalayas, Rockies, and Alps
• Has similar cold, windy conditions to Arctic tundra, but the soil usually has no permafrost layer

Polar Bear

• Roam the sea ice hunting seals — their primary food source
• Thick fur and 4 inches of blubber protect them from Arctic cold
• Mothers den in snowdrifts to give birth during the coldest winter months

Musk Ox

• Have two layers of fur — a coarse outer layer and a soft inner layer called qiviut
• Form a defensive circle with horns outward when threatened by wolves
• Use their hooves to dig through snow to reach the frozen plants beneath

Arctic Hare

• Coat turns brilliant white in winter and gray-brown in summer for camouflage
• Can run up to 40 mph — one of the fastest animals in the Arctic
• Thick fur and compact body shape minimize heat loss in bitter cold

Lemming

• Stay active all winter under the snow in tunnels — they don't hibernate
• Population boom-and-bust cycles affect the entire tundra food web
• A critical food source for foxes, owls, and other Arctic predators

Arctic Moss

• Grows in damp places, including bogs and the edges of Arctic lakes, and soaks up water and nutrients for the short summer
• Grows extremely slowly — just a fraction of an inch per year
• Provides insulation and nesting material for many Arctic birds

Lichen

• Not a single plant — a partnership between fungi and algae living together
• Can survive being completely frozen and revive when thawed
• A critical food source for reindeer and caribou in winter

Dwarf Willow

• One of the smallest woody plants — it hugs the ground, growing only a few inches tall, to stay below the wind
• Roots spread wide and shallow across the active layer above permafrost
• Provides food for Arctic hares, musk oxen, and ptarmigans

Cotton Grass

• Distinctive white fluffy seed heads sway in the wind across the tundra in summer
• Can bloom and set seed in just a few weeks during the short growing season
• Grows in wet, boggy areas above permafrost across the Arctic

What is the tundra biome?

The tundra is the coldest biome. It has no trees, very little precipitation (about 6 to 10 inches a year in the Arctic, counting melted snow), and a short growing season of roughly 50 to 60 days. The ground below the surface is permanently frozen, a layer called permafrost.

Where is the Arctic tundra biome found, and what is alpine tundra?

Arctic tundra is found in the far north, beyond the tree line, in places like Alaska, Canada, Russia, Greenland and Scandinavia. Alpine tundra is found on high mountains, above the height where trees can grow. Alpine soil drains well, and it is cold at night but its growing season is longer than the Arctic's.

What is permafrost?

Permafrost is ground that stays at or below freezing (32°F) for at least two years in a row, and in many places for thousands of years. It can be less than 3 feet thick in some places and over 4,900 feet thick in others. Only a top layer, called the active layer, thaws each summer.

Why are there no trees in the tundra?

It is too cold and the growing season is too short for trees. Permafrost also blocks deep roots, so plants only have a thin layer of thawed soil to grow in. That is why tundra plants are low shrubs, grasses, mosses and lichens.

What plants and animals live in the tundra?

Arctic tundra animals include lemmings, caribou, Arctic hares, Arctic foxes, wolves and polar bears. Alpine tundra animals include pikas, marmots and mountain goats. Plants are low to the ground, such as shrubs, sedges, grasses, mosses and lichens.