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Sepioteuthis sepioidea, Caribbean Reef squid

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Sepioteuthis sepioidea, the Caribbean Reef squid, is commonly observed in shallow near shore water of the Caribbean by divers and snorkelers. These squid are often confused with cuttlefish because they have large fins that wrap around their mantles. They are also broader than many squid and these traits make them look like cuttlefish (Sepia). Actually, if you look at their scientific name you will see that scientists also noticed that these guys look like cuttlefish—the "Sepio" which is in the genus and specific name refers to the fact that they look like cuttlefish while the "teuthis" tells one that they really are a squid. For the record, there are no true cuttlefish (Order Sepiida) off of North America although there are some Sepiolids.

I've had the pleasure of working on the inaugural 1998 squid communication study in Bonaire with Dr. Jennifer Mather, Roland Anderson, Alison King and others. This study was such a success that it has been ongoing ever since and in 2001 I was once again in Bonaire observing reef squid behavior. Believe me, these squid are very interesting to watch, especially at dawn and dusk when the mating displays are most common. The rapid color, shape and texture changes of these squid are amazing and it takes both still images, to capture the detail, and video, to capture the rate of change, to truly show what these animals are capable of. In 2001 we were filmed for 10 days for a Discovery Channel special. I can tell you that some really amazing underwater footage was captured and on the new HD format. I'm looking forward to returning to Bonaire again!

School of Caribbean Reef Squid in their typical daytime basic brown coloration. The images shown here were taken by James Wood with a Nikonos V during the 2001 study of communication in reef squid in Bonaire. This project is led by Dr. Jennifer Mather and has been ongoing since 1998.

A lighter shade of pale. When a predator swims by the squid quickly change color, often to pale and jet away.

Another trick they do when predators are around is a dynamic pattern. The squid orients itself perpendicular to the predator and stretches out its mantle and fins making it look larger. It also flashes 2 or 4 eye spots. In this case, the signal was directed at me as I was getting to close with my camera.

Ruth Byrne an graduate student of the Konrad Lorenz Institute in Austria were able to accurately identify over 100 squid based on the patter of dots on their fins. This enabled the team to follow the same squid every day.

Same squid, different color. Not only is the range of colors is amazing in these animals but the speed of the changes is incredible!

This is a courting pair of squid. The male (top and underneath) is doing a really nice stripe display while the female is doing a partial saddle.

Sometimes things heat up. These two males are displaying zebra displays to each other. This can escalate to both squid rising in the water column and challenging each other. The winner gets the female—well if she hasn't left both of them for a third squid that is. During these contests the males are very visible and oblivious to predators.

Can animals send two completely different messages at once? Squid can! The male in the middle of this image is giving the male on the left the zebra with half of his body and signaling an entirely different thing to the available female on the right.

If all goes well, the couple will be swimming parallel to each other, occasionally changing directions, and signaling saddle (interest?) and stripe (intention to mate?). This can lead to a very fast mating—if you blink you missed it.

We were extremely lucky to observe, film and photograph egg laying in Caribbean Reef squid. The female, escorted by her partner, finds a rock and attaches her eggs to the underside of it. In a few months both squid will be dead and the next generation will continue the cycle.

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The Cephalopod Page (TCP), © Copyright 1995-2018, was created and is maintained by Dr. James B. Wood, Associate Director of the Waikiki Aquarium which is part of the University of Hawaii. Please see the FAQs page for cephalopod questions, Marine Invertebrates of Bermuda for information on other invertebrates, and and the Census of Marine Life for general information on marine biology.