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Meet an eight-legged actor

If you think the Oscar nominees are good at pretending, wait till you hear what this octopus can do

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If the mimic octopus really can imitate these and other animals, the biologists will need hundreds more hours of videotape to prove it.

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A missing piece of the puzzle

The mimic octopus does seem to be a wonderful actor, but one "player" in the drama is still missing. Animals don't evolve mimicry to impress divers, biologists, and readers of The Christian Science Monitor. What predator is the mimic octopus trying to fool?

"It would be nice to find the predator," Hanlon says. "We don't know who is preying on the octopus, so we have to guess. Who is watching all this? What did the mimicry evolve for?"

Scientists are also still guessing why the octopus mimics many different animals. Tregenza thinks that a predator faced with lots of mimicry is less likely to see through the octopus's deception.

The mimic octopus has enough tricks up its eight sleeves to keep predators - and biologists - watching its act for a long time.

For more on the mimic octopus

A short video clip of the mimic octopus impersonating a flatfish can be viewed at: www.macdonaldproductions.com/preview.html

For more information on how squids and octopuses make their rapid color changes, go to: hermes.mbl.edu/services/MRC/adaptive.html

Biologist Roger Hanlon will be back in Indonesia next December, trying to solve the mystery of the mimic octopus. Interested volunteer divers should check out: www.coralreefalliance.org/travel/kungkunganbay.html

A round of applause, please, for this cast of animal impersonators

Around the coral reefs of the South Pacific, everybody loves the cleaner wrasse. The little striped fish grooms larger fish, picking off tiny parasites and dead scales. Instead of lunching on the cleaner wrasse, larger fish line up to get the wrasse's "beauty treatment."

Enter the sabre-toothed slime fish. It looks and acts like a cleaner wrasse - except it has two long sharp teeth. Instead of grooming the larger fish, the sabre-toothed slime fish swims up behind it, takes a big bite, and zips away.

Best supporting actor (playing a bad guy): scarlet king snake

We often use red, black, and yellow as warning colors. Think of fire alarms and "danger" signs. These are also nature's warning colors. The poisonous coral snake of the Southeastern United States has bright bands of red, black, and yellow that say "watch out!" The harmless king snake's similar color bands help it scare off predators, too.

Best special effect: comet fish

If a toothy predator were chasing you, would you stick your head in a hole and wave your bottom around? Probably not, but that's what the comet fish does.

This small fish from the tropical Pacific is dark brown with tiny white dots, just like a common (and fierce) moray eel. The comet fish also has an "eye spot" near its tail that looks like the eye of a moray eel. When chased by a bigger fish, the comet fish dives headfirst into a hole and wiggles its "fake eel" fanny.

Best costume: viceroy butterfly

Imagine putting a tasty-looking chocolate in your mouth - and biting down on a bar of soap! That's how a bird feels when it tries to eat a lovely-looking, nasty-tasting monarch butterfly. Once a bird has tried a monarch, it stays away from the black-and-orange insect. The tasty (to a bird) viceroy is slightly smaller than the monarch, but mimics its beautiful colors. So when a bird sees a viceroy, it thinks "yuck!" not "yum!"

A makeup artist's bag of tricks

Imagine you could instantly turn your curly red hair and freckles to straight black hair and olive skin. An octopus does something like that. It can change its color.

An octopus's skin contains pinprick-size sacs of color. The color sacs come in red, brown, yellow, and black. Tiny muscles surround each color sac. If an octopus wants to turn red, it flexes the muscles surrounding only the red color sacs. When the red color sacs are open, the octopus looks bright red.

What if an octopus wants to look blue or green? It doesn't need color sacs for those colors. It has tiny plates in its skin that reflect the blue-green color of the water. When an octopus wants to look blue, it "turns on" its reflectors. Using its color sacs and reflecting plates in combination, an octopus can be blue-spotted, red-striped, or almost any other combination. An octopus in Tahiti was videotaped changing its "look" 177 times in an hour - three times a minute!

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