Deep blue wonders

THE FIRST TIME I saw a cuttlefish swimming in the wild I was astounded by how prehistoric and alien it looked. Cuttlefish are astonishing creatures with heads like elephants, eight arms that they occasionally splay then join together like a trunk, and small bodies ringed with thin, rippling fins that look like a silk shawl. They glide across the ocean floor, changing their colour to match the surface underneath them, – from gold above sand to brown and red over seaweed – and even their texture – from smooth to thorny – blending in with the background so effectively that they are often only noticeable when they move their silken frills.

Cuttlefish are not just otherworldly in appearance, consider these facts: their pupils are shaped like the letter W, and it’s speculated that cuttlefish eyes are fully developed before birth and that the young start observing their surroundings while still in the egg. Their blood is colourless until exposed to air, when it turns blue-green. They have three hearts and a doughnut-shaped brain that is larger in proportion to its body size than that of any other invertebrate. The cuttlefish bone – that white oval-shaped object you often see washed up on beaches or in budgerigar cages – is actually a thick, calcified internal shell