Despite its name, the cuttlefish is a cephalopod, not a fish. It’s related to the squid, with eight arms and two tentacles armed with suckers to hold on to its prey. The internal “cuttlebone” made of aragonite (a form of calcium carbonate) supports the cuttlefish’s body. The hollow spaces in the cuttlebone are divided into many chambers, and the cuttlefish controls its buoyancy by controlling the amount of air inside the chambers. Cuttlefish eat crabs, shrimp, fish, octopuses, worms, and other cuttlefish, while they get eaten by dolphins, sharks, bigger fish, seals, and seabirds.
Cuttlefish are known as the “chameleon of the sea”. Don’t be too disappointed if you don’t see a cuttlefish while diving or snorkeling – this just means that it’s doing its job right! Cuttlefish have the amazing ability of mimicking the color of their environment so well that they become practically invisible. They manage to do this because of the three different types of cells that work in combination: the pigmented chromatophores, the leucophores that reflect while light, and iridophores that produce metallic colors. The chromatophores contain red, yellow, brown, and black pigments and the muscles around each chromatophore flex or relax to control which colors are visible or hidden. Cuttlefish skin has up to 200 chromatophores per square millimeter – comparable to high-definition TV! As leucophores reflect white light, the color they give changes with the depth of the water. They look white in very shallow water but turn blue and green as they go deeper. Iridophores contain stacked plates of crystals made from guanine that scatter the light passing through them, producing metallic blue and green colors. Did you know that cuttlefish can also change the sculpture of their skin to look like rocks or seaweed? It’s true! As bands of circular muscle under their skin contract, the near liquid in the center is forced up to form nodes, spikes, or flat blades that stick up.
Palawan is home to thousands of species of animals, both above and below the water. Come visit us to see them in person!
Cuttlefish Change Color, Shape-Shift to Elude Predators (National Geographic)