What Divers Should Know About Squid

Squid are active open-water predators, occupying a similar ecological role to teleost fish. These soft-bodied molluscs possess an elongated body, large eyes, eight arms, and two distinct tentacles, all surrounding a powerful beak. Their internal anatomy includes a small, rod-like gladius or pen that provides stiffening and muscle attachment. Displaying bilateral symmetry and a mantle, squid move primarily through precise jet propulsion from a funnel, enabling them to be rapid and strong swimmers. Some species can even "fly" for short distances out of the water.

Highly intelligent for invertebrates, some groups, like Humboldt squid, have been observed hunting cooperatively. Their acute sight helps them locate prey, which they seize with two long tentacles and secure with eight arms before using their beak to cut food. Squid can change colour for camouflage and signalling, a noteworthy trait. Many species employ ink clouds to distract predators, while some are bioluminescent, utilizing light for counter-illumination. These fascinating cephalopods typically have an annual life cycle, growing fast and spawning before dying.