What are cuttlefish?
They belong to the cephalopod classification, along with squid and octopus. They have one internal shell called a cuttlebone and, despite their name, they are not fish, but mollusks.
The several species all share some of the same characteristics. They have 10 arms and their body is built around a central shell called cuttlebone, which you might sometimes find washed up on shore. Unlike their cousins the squid, cuttlefish have a flat body. Their size varies from a few inches (flamboyant cuttlefish, dwarf cuttlefish) to over 1.5 feet long (50 cm) for the giant cuttlefish.
These animals have great camouflage abilities, which they use mainly for defense against attacks from fish and other predators. Just like octopus and squid, they have a sack of ink that it can deploy to escape an attack. They are very efficient hunters, capturing small fish, crabs and other prey with tentacle movement so fast that it is sometimes hard to see.
Where do they live?
Cuttlefish live in most the oceans around the world, in both temperate and warm water. They favor shallow water but can live as deep as 1,900 feet (600 m). Common species vary from location to location, with over 120 known different types.
Depending on your location, you might be able to spot some of these incredible chameleons of the sea on your dive. They can change color and patterns within a second to scare off a predator or to communicate with another cuttlefish. During mating season, males display some specific patterns to attract and seduce females. Some of the patterns last only a few seconds, while some remain longer.
Some common species
Let’s look at a few of the most famous species and where you can find them.
You can spot the tiny flamboyant cuttlefish in Indonesia, the Philippines, Malaysia and northern Australia. Its incredible color patterns vary from black to yellow to purple to white, making it a favorite among photographers and macro lovers. It “walks” on the seafloor rather than using its mantle to swim.
You can only find the giant cuttlefish, the world’s biggest, on the southern coast of Australia. Adults can weigh over 22 pounds (10 kg). One of the most spectacular times to see them is during the annual mating aggregation in Whyalla. Thousands of animals populate the shallow waters from mid-May through July each year, first spawning and then dying.
One of the smallest species, the dwarf cuttlefish grows only up to 2.75 inches (7 cm). You can find them from Indonesia up to northern Australia.
Their camouflage abilities can make it quite difficult to spot these critters, but they are quite common on reefs around the world. Even the common broad cuttlefish can display over a dozen different patterns. So, next time you’re diving, watch the reef carefully and see if you can’t spot this curious cephalopod.