Gills, a Heart, a Lens, an Ink Sac… The Wonders of Life We Found Inside a Squid
I’m Ken Kuwako, the Science Trainer. Every day is an experiment!
Hidden Treasures Inside a Squid? A Science Club Dissection Adventure
Have you ever heard someone say, “We’re going to dissect a squid,” and thought, “Wait… the same squid we eat for dinner?” That’s exactly how many people react at first. But once we picked up a pair of kitchen scissors and carefully opened one up, we discovered an incredible world of biological engineering hidden inside. Today, I’d like to share the excitement and discoveries from our science club’s squid dissection.
Here’s the squid we bought for the activity.
For many middle school students, the word “dissection” can sound a little intimidating. But once they realize they’re working with the same squid that’s often served at the dinner table, the tension quickly melts away. Squid are actually ideal for beginners because their organs are compact and easy to examine. During our science club meeting, everyone worked together, discussed their observations, and enjoyed a relaxed, curiosity-filled atmosphere from start to finish.
Materials and Preparation
For this activity, we prepared the following:
– Fresh or frozen Japanese flying squid (one per student or group is ideal)
– Kitchen scissors
– Tweezers
– A tray or an opened milk carton as a work surface
– Disposable gloves and newspaper
– Soy sauce (for observing the stomach)
We also followed an excellent squid dissection video available on YouTube. Watching it together before starting helps everyone understand the overall procedure.
Opening the Squid
Using kitchen scissors, we carefully opened the squid’s body. Unlike preparing food in the kitchen, this time every cut came with a question: “What’s hiding inside?” That sense of curiosity is what makes dissection so fascinating.
To everyone’s surprise, we found that squid have clearly recognizable gills and even a heart.
“So squid really do have gills, just like fish!”
The students were amazed. Although squid don’t look much like fish, they also breathe by taking oxygen from the water through their gills.
Next came one of our favorite discoveries. We gently poured soy sauce into the squid’s mouth, and suddenly the shape of the stomach and its internal pathways became much easier to see. The dark color of the soy sauce highlighted structures that would otherwise have been difficult to distinguish. It’s a wonderfully simple trick, yet it perfectly demonstrates the kind of creative thinking scientists use when making invisible structures visible.
Then we turned our attention to the squid’s eye.
Inside, we carefully removed a beautifully transparent lens.
A squid’s eye is remarkably similar to the human eye, complete with a sophisticated lens that allows it to focus underwater. Even more fascinating, squid and humans evolved these similar eye structures independently. This is a classic example of what biologists call “convergent evolution,” where completely unrelated organisms arrive at strikingly similar solutions to the same challenge.
Finally, we examined perhaps the squid’s most famous feature: the ink sac. When we carefully removed and opened it, thick black ink slowly flowed out.
Squid ink does much more than create a cloud of darkness. Because it’s slightly sticky, it can hold its shape underwater for a short time, forming a decoy that distracts predators while the squid escapes.
Moments like these are impossible to capture fully in a textbook diagram. Seeing how an organ’s structure directly relates to its function makes biology come alive in a way that pictures simply can’t.
Why Even First-Time Dissections Went So Smoothly
This was actually our science club’s very first squid dissection. Even so, the students approached the activity with confidence and curiosity. One reason was that the day before, they had already completed a pig eye dissection.
Because they had already practiced handling the tools and making careful observations, they were able to focus naturally on exploring the squid’s anatomy. It reminded me how valuable it is to build scientific skills step by step.
Dissection is sometimes seen as a special or unusual science activity, but in many ways it represents the very heart of scientific inquiry.
“Why is it built this way?”
“What did this organ actually do?”
Questions like these not only reveal the amazing design of living organisms but also encourage students to develop a deeper appreciation for life itself.
Squid dissections are inexpensive, safe, and packed with fascinating discoveries, making them an outstanding teaching resource. Whether you’re running a science club or teaching biology in the classroom, this activity is sure to spark students’ curiosity and inspire them to ask even more questions about the natural world.
Contact and Collaboration
Science is full of amazing surprises, and I love making them easy and fun to explore! On this site you’ll find plenty of hands-on science experiments you can try at home, along with practical tips and explanations. Feel free to look around!
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