Download Understanding Squid

Honors Biology
Mr. Velazquez
Understanding Squid
The Squid is an invertebrate (animal without a backbone) that swims in the oceans.
This mollusk is closely related to the octopus. Squid can change the color of their skin to
mimic their environment and hide from predators.
Squid are soft-bodied cephalopods. They move by squirting water from the mantle
through the siphon, using a type of jet propulsion. When in danger, squid squirt a cloud
of dark ink in order to confuse their attacker and allow the squid to escape. Squid
reproduce by releasing eggs into the water. Some squid eggs are free-floating, others
are attached to seaweed or to the ocean floor.
Anatomy: Squid range from 1 to 60 ft (0.3 to 18 m) long. The biggest squid is the Giant
Squid (Architeuthis). Squid have a large mantle/head (with a large brain), eight arms with
suckers, two longer feeding tentacles, a beak, a large head, two large eyes, and two
hearts. Their large eyes are very similar in structure to people's eyes. They breathe
using gills.
Diet: Squid eat fish, crustaceans (like shrimp), and other squid. These fast-moving
carnivores (meat-eaters) catch prey with their two feeding tentacles, then hold the prey
with the eight arms and bite it into small pieces using a parrot-like beak. The esophagus
runs through the brain, so the food must be in small pieces before swallowing.
Predators: Many animals prey upon squid, including many sharks and other fish, some
whales, squid, and people.
Classification: Kingdom Animalia, Phylum Mollusca, Class Cephalopoda, Order
Teuthoidea, Families Loliginidae, Sepiolidae, and Architeuthidae.