Marine invertebrates
CITE
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Squid. (2022). In Q-files Encyclopedia, Life, Marine invertebrates. Retrieved from
https://www.q-files.com/life/marine-invertebrates/squid
"Squid." Life, Marine invertebrates, Q-files Encyclopedia, 10 Feb. 2022.
https://www.q-files.com/life/marine-invertebrates/squid.
Accessed 19 Mar. 2024.
Squid 2022. Life, Marine invertebrates. Retrieved 19 March 2024, from
https://www.q-files.com/life/marine-invertebrates/squid
Life, Marine invertebrates, s.v. "Squid," accessed March 19, 2024.
https://www.q-files.com/life/marine-invertebrates/squid
Squid
Squid have eight arms and two longer tentacles attached to their heads. Their bodies are enclosed in a mantle, with a fin on either side. They move by sucking water into their mantles via a siphon, then blasting it out again in a powerful jet. Their streamlined shape enables them to glide through the water at high speed. Squid have an internal shell, called a pen, that protects their inner organs. They have extremely large eyes and good eyesight for catching their prey of fish and shrimp. Squid can change their colour in seconds, a feature they use to scare off predators.
Arms and tentacles
Squid are carnivorous. Their favourite foods include small fish, crabs, shrimp and other squid. A squid stalks its prey by hiding out of sight until it comes within range, then shooting out its arms to capture it. The squid then pulls the animal to its mouth with its arms. Its sharp, horny beak is used to tear the prey into small pieces before eating it. Squid have two long tentacles on either side of their mouths. They use them for gripping or feeling objects, or for movement.
Giant squid
The giant squid is, after the little-known colossal squid, the second longest invertebrate. Including its ten long, sucker- and hook-covered arms, it can measure up to 13 metres (43 feet) in length, of which about 5 metres (16 feet) is the body. The giant squid’s huge eyes help it to see prey in the dark ocean depths, where it lives. No one had seen a live giant squid until one was photographed in 2005. Before that they were known only from washed-up dead specimens and the stomach contents of sperm whales, their chief predators.
Firefly squid
Although only 8 centimetres (3 inches) long, the firefly squid can make itself noticed with the light-producing organs at the tip of its tentacles. It flashes them on and off to attract small fish, then pounces on them with its powerful arms. The squid's whole body can light up, creating dazzling patterns to attract a mate or confuse a predator.
Cuttlefish
Cuttlefish have eight arms and two tentacles with suckers which they use to grasp their prey: small molluscs, crabs, shrimp and fish. They possess an internal shell called the cuttlebone, which provides them with buoyancy,
Giant cuttlefish gather to mate off the coast of southern Australia in August. Larger males are more likely to gain attention, so smaller males, too small to fight for dominance, must work hard to be noticed by females. Males usually change colour to show their interest in a female, but small males may change colour to look more like females. While the larger males are fending off rivals, the smaller “mimic” swoops in on a female, unnoticed by other cuttlefish.
Consultant: Chris Jarvis