Arctic Animals.

雪儿 · 发表于: 2011-6-26 18:56:14

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雪儿 · 发表于: 2011-6-26 18:56:32

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Photograph by Steven J. Kazlowski/Alamy

Arctic Fox—Fall

Decreasing daylight triggers these Arctic animals' bodies to make less of the pigment melanin. Melanin is the substance inside hair or feathers that gives them color.

雪儿 · 发表于: 2011-6-26 18:56:45

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Photograph by Daniel Cox/Photolibrary

Arctic Fox—Winter

Once a fox stops producing much melanin, its whole coat is a dazzling white. In the spring the reverse happens.

雪儿 · 发表于: 2011-6-26 18:56:57

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Photograph by Tim Fitzharris/Minden Pictures

Snowshoe Hare—Summer

Snowshoe hares are well known for their patchy-colored camouflage.

雪儿 · 发表于: 2011-6-26 18:57:12

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Photograph by Doug Lindstrand/ Alaska Stock

Snowshoe Hare—Fall

Their winter hair grows in patches, rather than showing up evenly.

雪儿 · 发表于: 2011-6-26 18:57:28

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Photograph by Michael Quniton/Minden Pictures

Snowshoe Hare—Winter

This adaptation makes it difficult for predators to distinguish them from the landscape.

雪儿 · 发表于: 2011-6-26 18:57:44

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Photograph by Michael Durham/Minden Pictures

Collared Lemming—Summer

Collared lemmings are the only rodents with coats that change to a white color. They have another interesting adaptation to winter.

雪儿 · 发表于: 2011-6-26 18:57:56

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Photograph by Andrey Zvoznikov/Nature Picture Library

Collared Lemming—Winter

As snow starts to fall, lemmings grow oversize claws on the third and fourth toes of their front feet. This allows them to dig tunnels in the snow all winter. Staying below the surface helps them avoid predators while they shovel in search of food. By spring, their intense burrowing wears down their claws to a normal size again.

雪儿 · 发表于: 2011-6-26 18:58:11

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Photograph by Michael Durham/Minden Pictures

Ptarmigan—Summer

The ptarmigan (TAR-mih-guhn) is a bird with feathers that change from brown to white, providing camouflage in the snow.

雪儿 · 发表于: 2011-6-26 18:58:24

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Photograph by Chris Schenk/Minden Pictures

Ptarmigan—Fall

Feathers on their legs and feet help keep the birds warm. Downy feathers close to their skin trap body heat. Just as insulation in a house keeps warm air inside during winter, this bird's natural insulation makes freezing conditions more bearable.

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