By Kathy Kranking; Photos by Brandon Cole

Each year, thousands of cuttlefish gather along the coast of Australia. What’s going on?

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These giant cuttlefish come here for a very special reason: It’s mating time! Males fight for the right to mate with females, and then females lay their eggs. But the cuttlefish aren’t the only ones that come here—scientists, photographers, reporters, and tourists do, too!

This area, near the town of Whyalla (see map above), is famous because it’s the only place in the world where cuttlefish gather in such large numbers. So many come that people have given it the nickname of “Cuttlefish Coast”!

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Cuttlefish aren’t fish. Instead, they belong to a group called cephalopods (SEF-uh-luh-pahdz). Their closest cousins are octopuses and squids. Giant cuttlefish are—you guessed it—the biggest kind of cuttlefish. They can grow to be longer than your arm!

But let’s get back to the action. The mating season for giant cuttlefish starts in May and goes until late August. Scientists don’t know for sure why the cuttlefish gather in this particular area along the coast. But it may be because the seafloor there is covered with lots of flat, overlapping rocks. That means there are lots of spaces between the rocks for females to lay their eggs.

When a male finds a female to mate with, he tries to impress her by putting on a dazzling show. Cuttlefish are able to change the look of their skin in less than a second! They flash neon rainbow colors, create patterns of dots and lines, or even make stripes move in waves across their bodies. This show can say to females, “Let’s mate!” It may also tell other males to “back off!”

But even after a male cuttlefish finds a female he wants to mate with, he has his work cut out for him. There can be four or more males for every female on the mating grounds! A male trying to attract a female could have several other males nearby trying to do the very same thing.

Flashing his colors is one way for a male cuttlefish to warn other males away. But he can also use other tricks. One is to spread out his arms to make himself look bigger and scarier. Another is to shoot a blob of “ink” from his body to confuse the other males. And sometimes males actually fight, each biting with the sharp beak at the center of his arms. In the worst cases, a male could end up losing an arm or two in these battles.

Tap image for a closer view.

The biggest, strongest male cuttlefish are great at guarding females from other males. So you might think smaller males would be out of luck in the mating game. But some small males have a very tricky trick. These males are called “sneakers,” and here’s why: While the bigger males are busy wrestling with each other, a smaller male will quietly change his colors to match the colors of a female. In this disguise, he slips past the males and then mates with a female without the bigger males noticing! Sometimes being sneaky can pay off.

Once a male and female cuttlefish have mated, the female begins laying her eggs. She attaches each tear-shaped egg carefully to the underside of a rock. A female often mates with more than one male, so she may lay hundreds of eggs in all.

After she lays her eggs, the female leaves. Now they’re on their own. In three to five months, the baby cuttlefish will hatch. They are mini models of their parents, able to swim and shoot ink right away.

In another year or two, these cuttlefish will be grown and ready to mate. And then it will be their turn to join the action back at “Cuttlefish Coast”!

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