Welcome to the Squid Page:

Squids are cephalopod molluscs. They are closely related to octopi and in the same phylum as clams and snails. Squid have generally long, arrow shaped bodies, with a pen (internal shell-like shaft). They have 8 arms and 2 tentacles that they use to capture prey. They move by jet propulsion, by sucking water into their body cavity and expelling it with great speed. Cephalopods are thought to be the most intelligent of all molluscs and possibly of all invertebrates. Their diet consists mainly of fish, crustaceans (crabs, amphipods, krill etc), and worms. Squids range in size from the giant squid (Architeuthis sp.) to the smallest Idiosepius sp. The largest giant squid ever recorded (Architeuthis princeps) was captured in 1878. One of the "arms" (probably a tentacle) measured 35 feet long. It is estimated that the animal weighed in the neighbourhood of 4000 pounds. The smallest Idiosepius squid found was 6mm. Squids are very diverse. So for your report you might want to pick one genus or species to look into more in depth. The loligo squid is the most common squid worldwide.

FAQ:
Respiration of Octopods
Squid Color Vision
Octopus Information

Respiration of Octopods

Q: Can you tell me about the respiration of octopods?

A: Cephalopods (including octopi) are different in many ways from all other molluscs. They are considered more advanced - in terms of intelligence, sensory structures, and cardiovascular systems.

They breathe via a pair of ctenidia (gills). Unlike other molluscs, they have no countercurrent exchange system. In a countercurrent system, the blood flows in one direction, while the water flows in the opposite direction. This ensures the most efficient transfer of oxygen in, and carbon dioxide out, of the body. Water flow across the gills is maintained by cilia in lower molluscs, but in cephalopods, water flow is caused by the constant filling and emptying of the mantle cavity that occurs during jet propulsion movement. Gas exchange occurs during the slow filling of the mantle, rather than on the rapid emptying.

Squid Color Vision

Q: 1. What attracts squid to the lights that commercial squid fishermen shine on the water?
2. Is there any specific color light that attracts squid the least and greatest?
3. The squid I see in the Channel Islands,CA are about six inxches long. By chance, could you tell me what type of squid this may be?

A: Experiments have shown that squid are attracted to white light, and so lights are often used for fishing. Squid, and other cephalopods, have excellent eyesight - rivalring our own. I am not sure exactly what attracts to them to the light. Some squid are also capable of bioluminescing (they can light up themselves!), so perhaps light attraction is for communication purposes. It is not clear what individual colours in the spectrum that squid are attracted to. Many commercial and government docks now use yellow/orange lights and these do not seem to attract the squid. Scientist need to do more research to find out why.


Octopus Information

Q: Why does an Octopus have three hearts?

A: Basically an octopus has three hearts because it needs them for blood circulation and gas exchange. The octopus has one main heart that drives the blood in its body. But here comes the interesting part. Octopi have something called a booster heart (branchial heart) that pumps blood into the capillary networks of the Ctenidia where gas exchange takes place. Basically the extra hearts of the Octopus are for assisting in the uptake of oxygen and the releasing of carbon dioxide. Without these extra hearts the Octopus might not be able to breathe properly.

Up