Departamento de Ciencias
Laboratory #1
Squid Dissection
Sergio M. Alegre -------- October 19, 2007
Gilberto González ------- Prof. Wilma M. Giol
Carlos Rosario ----------- Biología II
Squids are classified in the animal kingdom with the following taxonomy: the kingdom is Animalia, the phylum is Molluska, the class is Cephalopoda, the order is Teuthoidea, the family is Loliginidae, the gene is Loligo, and the species Pealleii. Squids are one of the most developed invertebrates on the animal kingdom. In size, the smallest squid tend to be 2.5 centimeters long, but the giant squid ever recorded so far was 20 meters long and weighted more than 1000 pounds. All mollusks have a soft body, which is why they have a skin cote known as the mantle to protect internal organs like hear, stomach, and gills.
Squids have the ability to change color to blend into their surroundings. They use this technique to protect themselves, or to attract mates during courtship season. These changes in colors come from chromatophores which are pigments cells located on the squids outer skin layer. The change in color occurs when these cells expand and contract to either show or hide different color like blue, red, yellow, and other. Unfortunately squids aren’t very fast swimmers. Squids move using their fins and a jet propulsion which happens when the squid pushes water out of its body through the siphon. Their speed can reach a limit of 23 miles per hour using their fins which are located at the end of the mantle. If this speed isn’t enough to get out of danger one of the squid’s most known defense mechanism kicks into action, the famous ink spraying. When squids feel that they are in some kind of danger their ink sack produces a mucous type of ink which is released through the siphon and one it’s out it confuses the predator giving the squid the time it need to escape.
Squids have a total of ten arms, eight of them are short and the last two are long. The two long arms are called tentacles which only have suction cups at the end of the tentacle and the purpose of these two arms is to catch the prey. The squid’s diet consists on small crustaceans, fish, marine worms, and even other squids. After catching the prey the last eight remaining arms, which are completely full of suction cups, are in charge of pushing the prey into the beak, a structure build like the beak of a parrot to break down the shell of other mollusks that form part of the squid’s diet. Another part of the squids mouth that allow the prey to be broken down more easily is the radula, a type of sharp teeth that cover up the tongue muscle to drill up other mollusks with shells.
Female and male squids differ in the color of their reproductive organ, the male’s gonad is white and the female’s is clear. Squids don’t live a very long life, which is why during mating season females lay or release a very reasonable amount of eggs to ensure the continuation of the species. Fertilization occurs inside the female’s body when the male’s sperm store package called spermatophores penetrates the female’s mantle. After mating a female squid can produce ten to fifty egg strings each containing hundreds of eggs each. After laying the eggs will hatch in about ten to fourteen days and will reach full maturity in three to five years. Unfortunately for the parents, after mating most of them die after leaving the eggs on the spawning grounds.
The giant squid is the largest invertebrate in the animal kingdom. The giant squid has eyes bigger than a human head and are capable of detecting the smallest amount of life under the sea where they usually dwell. Giant squids live in depths of 660 to 2300 feet under the sea and because of these depths it’s very rare to spot one of these amazing creatures. Also they serve like food for sperm whales.
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