Winter

Winter is one of the four seasons of temperate zones. Astronomically, it begins with the winter solstice (around December 21 in the Northern hemisphere and June 21 in the Southern hemisphere), and ends with the spring equinox (around March 21 in the Northern hemisphere and September 23 in the Southern hemisphere). In meteorology, it is by convention counted instead as the whole months of June, July and August in the Southern hemisphere and December, January and February in the Northern hemisphere.

Ecology

Animals

To survive the harshness of winter, many animals have developed different behavioral and morphological adaptations:

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• Migration is a common effect of winter upon animals, affecting basically birds. However some birds, i.e. the cardinal do not migrate.
• Hibernation is a state of reduced metabolic activity during the winter. These animals "sleep" during winter and only come out as warm weather returns. For example, gophers, bears, frogs, snakes or bats hibernate.
• Some animals store food for the winter and live upon it instead of hibernating completely. This is the case of squirrels, beavers, skunks, badgers and raccoons.
• Resistance is observed when an animal endures winter, but changes in ways such as color and musculature. The color of the fur or plumage are changed to white in order to be confused with snow and thus, to retain their cryptic coloration year round. Examples are the ptarmigan, the arctic fox, the weasel, the white-tailed jack rabbit or the mountain hare.
• Some fur-coated mammals grow a heavier fur coat during the winter. This improves the heat-retention qualities of the fur. The coat is then shed following the winter season to allow better cooling. The heavier winter coat made this season a favorite for trappers who sought more profitable skins.
• Snow also affects the ways animals behave, as many take advantage of the insulating properties of snow by burrowing in it. Mice and voles typically live under the snow layer.

Plants

Annual plants never survive the winter. As for perennial plants, many small ones profit from the insulating effects of snow by being buried in it. Larger plants, particularly deciduous trees, usually let their upper part die, but their roots are still protected by the snow layer.

Related Topics:
Annual plant - Perennial plant - Deciduous trees

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