Kings of Camouflage

TV Program Description
Original PBS Broadcast Date: April 3, 2007

Join NOVA on a voyage beneath the waves, where you'll discover a bizarre, alien-like creature like no other. It's an animal with eight sucker-covered arms growing out of its head, three hearts pumping its blue-green blood, and a doughnut-shaped brain. It has the ability to change its color and shape to blend in with seaweed and rocks, and it has a knack for switching on electrifying light shows that dazzle its prey. Perhaps most surprising of all, this animal is quite intelligent, with a highly complex brain. In this program, underwater cameras capture the extraordinary, transformative powers of the cuttlefish.

Not a fish at all, the cuttlefish is a cousin to the more well-known octopus and squid. Together, they are a part of the class of marine mollusks (soft-bodied animals without a spine) called cephalopods, or "head-footers." But while cuttlefish are lesser known, they are very clever. In fact, they have one of the biggest brain-to-body ratios of all invertebrates.

They also have a special talent. Mark Norman, a marine biologist and senior curator from Australia's Museum Victoria, is one of the film's featured experts and has studied cuttlefish for over 20 years. According to Norman, it is the cuttlefish's amazing capacity to rapidly change its color, pattern, and shape that makes this creature so intriguing. By pushing up different parts of its skin, it can camouflage itself against the reef. And with the striking displays of color and light on its skin, it can appear like an alien spaceship hovering in the water, intimidating mating rivals or even hypnotizing a tasty morsel like a crab before attacking it (see Quick Change Artists).

The program introduces viewers to the elusive Broadband cuttlefish, known for its particularly flashy light shows. By presenting the cuttlefish with various lures, including small crabs and a toy lobster, marine biologists seek to find out what makes this cuttlefish put on its amazing light displays, as well as whether it is intelligent enough to quickly understand if a lure is unattainable. (It seems to be: it only takes a few tries for a cuttlefish to lose interest after determining that a crab inside a glass jar cannot be caught.)

So how do cuttlefish develop their visual pyrotechnics? At the Marine Biological Laboratory in Massachusetts, Roger Hanlon shows viewers how it's done. The secret, he explains, lies in specialized layers of skin cells. The top layer features pigmented cells that provide most of the yellow, red, and brown patterning. By pulling out and pushing in different muscles, the cuttlefish can display various groups of pigmented cells. A deeper layer of iridescent reflecting cells in blue, green, red, and pink, as well as a white base, complete the palette.

"Kings of Camouflage" also showcases several other kinds of cuttlefish, including a tiny species called the Flamboyant cuttlefish. The size of an egg, it walks on the seafloor rather than swims. And then there are the amazing Giant Australian cuttlefish, which come together to breed off the south coast of Australia every autumn.

One of the most amazing displays of the Giant cuttlefish proves that they have plenty of brains and not just brawn. Small males, who cannot compete physically with their larger counterparts, have developed a cunning way to sneak in and mate with their desired female, by "dressing" as a female cuttlefish. They pull in their arms, change their colors to a mottled pattern, and glide by the larger males. Once this female mimic swims underneath and finds the female, he often as not successfully mates with her. (See Mating Trickery for other animals that practice crafty courtship.)

Cuttlefish go through only one of these mating cycles—they burn bright and die young, usually between 18 months and two years of age. With such a short life span, it is even more surprising that they are so intelligent. Jean Boal of Millersville University in Pennsylvania shows viewers how much, and how fast, cuttlefish can learn (see her interview). Boal creates a special enclosure to assess the cuttlefish's ability to figure out the right escape route. As it turns out, her cuttlefish are able to learn the rules of finding the open exit, and repeat their success trial after trial—yet another example of the smarts of this beguiling creature.

Program Transcript
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Behind these seemingly pensive eyes lies the biggest brain of all invertebrates, but just how smart are cuttlefish?

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