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5 clever animals that change costume

Come Halloween, people across the country will transform from everyday people to ghouls, goblins, and more. But humans aren’t the only ones who change costumes.

An Arctic fox with gray and white fur sits in the grass with yellow wildflowers in the background

© Christopher Cockerill / Swedish Arctic Fox Project

Check out the animals below that change their color, shape, and more seasonally or over time. Maybe they’ll inspire your next costume!

Arctic fox

A white winter-coated Arctic fox walks through snow in Churchill, Manitoba, Canada
Arctic fox during the winter

© Fritz Pölking / WWF

An young Arctic fox with mostly brown fur stands near its den in Lapland Finland
Arctic fox in warmer months

© Petri Piisilä / Metsähallitus / WWF

The magnificent Arctic fox changes costume with the weather. In the winter, the species dons a bright white or blueish-gray coat to blend into the snow covering inland Arctic areas. That coat changes to brown or gray when the snow melts, revealing the rocks and plants of the tundra. WWF works to support and protect fragile ecosystems like the Arctic so the Arctic fox and other wildlife may thrive.

Mimic octopus

A brown and white mimic octopus "walks" along the dark, sandy ocean floor
A mimic octopus "walks" across the ocean floor

© Francesco Ricciardi/Shutterstock

A mimic octopus assumes a light tan and white color to blend into the sand on the ocean floor
A mimic octopus changes color to blend into the sand

© Sascha Janson/Shutterstock

As its name suggests, the mimic octopus changes shape and color to resemble other marine animals, like flatfish, lionfish, seahorse, and crabs. In general, octopuses are known to change color, but the mimic octopus specifically takes the defense tactic a step further by also changing shape to avoid potential predators.

American goldfinch

A bright yellow and black American goldfinch with an orange beak sits on a small tree branch with flowers in the background
An American goldfinch in warmer months

© Element allqulity Designe/Shutterstock

A brown and black American goldfinch sits on a branch with brown leaves
An American goldfinch with winter plumage

© Brian Lasenby/Shutterstock

The American goldfinch sports luminous yellow feathers in the summer, making the species easy for birdwatchers to spot. But as the weather cools and winter rolls in, the goldfish dons subtle brown feathers.

Stoat

A brown-coated stoat stands on its hind legs inside Lacreek National Widllife Refuge
A stoat in the warmer months

© USFWS

A white winter-coated stoat peeks through rocks inside the Izembek National Wildlife Refuge
A stoat in the wintertime

© J. Sarvis / USFWS

The stoat is generally not the first species that comes to mind when we think of animals in cool climates. This weasel-like creature lives mainly in alpine meadows, marshes, and riparian woodlands, where it has a brown coat and a whiteish-yellow belly. But in very cold places, that coat—much like the one of the Arctic fox—turns pure white. This keeps the stoat camouflaged so it can hunt.

Monarch butterfly

A black and yellow monarch caterpillar climbs up the stalk of a milkweed plant
This caterpillar will transform into a monarch butterfly

© WWF-US/Clay Bolt

Action photo of a monarch butterfly in flight about to land in a field of goldenrod. It shares the plant with a bee.
A monarch butterfly flits its wings

© Morgan Heim / Day's Edge Productions / WWF-US

Monarch butterflies perform the ultimate costume change: shifting from a caterpillar to a beautiful, winged creature. Monarchs lay one small egg on a milkweed plant. That egg becomes a larva—what we know as a caterpillar—and eventually transforms into a pupa. After a time, the monarch will pump its wings and expand into a butterfly. WWF works to promote good forest management to preserve monarch habitat in Mexico and helps fight climate change that can impact monarch migration.

Three monarch butterfly plush against a white background

© WWF

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