Cuttlefish vs Squid: the Difference and Facts

indahs November 19, 2017

33rd edition of Marine Life monthly post. Marine Life post published every 19th of the month. It aims to share information about the marine life species and to promote their conservation. All images in this post are taken by Indah Susanti unless stated otherwise.

On my early days of scuba diving, I had difficulties to distinguish the Cuttlefish and Squid. They looked alike at first glance. Both are not fish, they are marine invertebrate that belongs to the group of cephalopods. That means they are marine animals characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles. The Cuttlefish is bulkier and wider compared to the Squid whose body is long. Another thing that distinguished the two animals is their backbone, which the Cuttlefish has brittle hard backbone while the Squid has a translucent body, some of the squid species have bioluminescent organs that glow in dark.

Cuttlefish

Squid

Compared to Squid, the Cuttlefish usually stay cool and stay around whenever seeing scuba divers. They are not as shy as the Squid. Squids usually swim away quickly whenever they saw humans with scuba gear. For sure, the Cuttlefish has a large brain and it is one of the intelligent marine invertebrates. As for the squid, it is known as the fastest of all invertebrates.

Cuttlefish stayed calm while I took its picture. Taken in Maluku (Indonesia).

One difference between the Cuttlefish and the Squid that obvious to see is their eyes shapes. The Cuttlefish has W-shaped pupils, that make them able to see from two pupils – basically, they can see in front of them and behind them at the same time. Something humans can only do when they are inside a car with parking assistance monitor screen 😀

Meanwhile, the Squid has round eyeballs which they can see a range of 360 degrees and their eyeballs are quite large. It is reported that the giant squid has eyeballs that are the same size as a standard basketball (source).

Cuttlefish

Squid

Despite these differences, both the Cuttlefish and Squid have three hearts and a short lifespan (one to two years). Their eyes sight capabilities are incredibly amazing but it looks like both animals are color blind.

I hope I will meet these marine animals again during my dives, as there are still more of their behavior to explore 🙂

Squids on the water surface during a night dive in Raja Ampat (Indonesia)

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