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Squid Dissection
Pre-Discussion:
Ask the students as a class what they know about squids. Create a list of questions (answers if they have any) on the
board which students can keep in mind while dissecting. Examples:
What type of animal are squids?
What do they eat?
How do they swim?
Dissection:
For the dissection, the students will have a list of body parts, and blank diagrams of the external and internal
organs.
External: Help them locate each organ and fill out the diagram. Ask them to note things like how many
tentacles and arms there are. Point out the function of each of them and how the shape connects to function (ie fins for
swimming, suction cups for grabbing, etc.).
Cool extra things to locate!
Beak: At the mouth, find the beak and show it to the students. It is possible to push out the beak and let
the students handle it.
Eyeballs: TUTORS ONLY: If you have time, slice open an eyeball and see if you can dissect out the lens
(round ball). Warning, a lot of black juice will come out.
Internal: Lay the squid on its “back” (laying on its fins) and separate the mantle from the organs. Carefully cut
the mantle up the length of the squid without harming the internal organs. Spread open the mantle so students can see
the organs. Help them identify and label each organ as with the external organs.
Things to keep in mind:
Male vs. female: If there are large, white glands laying on top of the organs, this is a female. You will
need to remove these organs to get a better view of things. Females may have jelly-like eggs at the “top” of the
mantle. Males will have a milky white sac instead.
Gills/heart: Point out the fact that there is more than one heart, and each gill has a heart. Advanced
question: Why do they have hearts for each gill? Try to explain how gills are like our lungs, and provide oxygen
for the blood.
Ink sac: TUTORS ONLY: Cut out the ink sac carefully without piercing it as the ink will spill and oscure the
organs. Lay it aside in a small cup where it will be used for writing later.
Stomach: The stomach is a long, white milky tube. If you can identify it, try cutting it open and see if you
can find a recent meal for the squid.
Head: you will have to cut through the tentacles to get to the brain. It is between the eyes and not that
obvious. If you come across a bunch of white goo, that’s the brain.
Gladius/Pen: The gladius will be along the mantle underneath the organs. It is thin, long, and like
cartilage. Grab the head and organs firmly and pull them away from the mantle. This will reveal the gladius,
which you can pull out.
Writing:
TUTORS ONLY: Remove the ink from the sac by cutting it and squeezing with forceps/toothpicks/whatever
works. Let it accumulate in the plastic cup. If the ink seems thick, you can add a little water to it. Let the students dip
the pointed end of the gladius (“pen”) into the ink and write their names on a piece of paper as a souvenir. If the gladius
is not firm enough, or broken, they can use toothpicks instead. Also, some ink sacs may be empty of ink, so share with
those that have empty ink sacs.