DEEP DOWN BY THE REEF

Caribbean reef squid - from Creative Commons

These are Caribbean reef squid. **Please read my post below this for a primer on these gorgeous creatures. They are found in the waters of the Caribbean, as well as in Florida and the Bahamas. In fact, if you are diving there and looking for squid, these are the only ones that will grace your presence. No other squid are visible in that area.

These squid travel in "schools" that are called shoals. Groups range in size from 4 to 30 adults. They hang out in the shallow parts of the water near reefs and can dive up to 100 meters.

Caribbean reef squid are sometimes confused with cuttlefish because they are more broad than most squid, and their fins wrap around their mantle. Like other squid, Caribbean reef squid have chromatophores, special skin cells that can change colors. This use of cells to change color is similar to how chameleons use their chromatophores to display mood or match their environment. But cepalopods such as squid and octopuses have a different body scheme. All chromatophores are cells which contain either pigment or light-reflecting surfaces. Chameleons are able to "translocate" their chromatophores in order to change colors.

Squid reef 2

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Cephalopods such a squid, however, have chromataphore cells which contain a kind of "sack". When the squid's nervous system is reacting to its environment, the muscles will contract and change the shape of the sack within each chromatophore cell. These reactions are controlled by individual neurons in the squid's nervous system, one at a time. That is why cephalopods such as squid appear to change color in "waves". 

This reaction changes the translucency, opacity or reflectivity in the squid's skin in dramatic ways. Cephalopods are also extremely talented in matching their background in not just color but also in texture. Caribbean reef squid in particular use this talent in a number of ways.

Reef squid can even display different colors and patterns on each side of their body simulatnaeously, such as when a male must court a female on one side with a nice mellow pattern and scare off a competing male with a scary zebra-type pattern on the other. A scientist at the Smithsonian Tropical Research Institute in the Bahamas studied Caribbean reef squid and believed that the reef squid use their displays as a kind of complex communication complete with nouns, verbs, and modifiers.

In his studies he came to believe that, like human language, the number of ideas that reef squid could communicate to others was infinite. The study was never completed before the scientist died, however. Caribbean reef squid will try to disguise themselves as they hunt. Some will take on the appearance of sargassum weed. Some will take on the appearance of the parrotfish which they are hunting. Juvenile reef squid have been observed to mimic their own ink blobs. 

Cephalopod's eyes are remarkably like our own. They have the ability to see with the same detail that humans do, and indeed the giant squid has the largest eyes of any animal on the planet. Other deep-sea species of squid can have eyes the size of headlights on a car. Unlike us, cephalopods can see polarized light. And the eyes of the cephalopod gives us clues to their level of intelligence. Cameraman Mike deGruy has this to say about cephalopods:

"We have a rapport with primates because we can make eye contact. That normally isn't there with fish and invertebrates. However, cephalopods will watch you when you walk into a room where they are in the tanks. It's an eerie feeling......"

I should also mention that the joyful photos of people catching squid to show off unusual species is quite revolting. Squid lose their majestic shape out of water because they depend on water to maintain their body shape. Also, they can survive for almost an hour out of water, so they suffer terribly if someone is just showing off and leaving it on their boat for fun. And the pictures of people showing off giant squid is absurd, because the giant squid is not the largest squid species. The colossal squid is. 

Cephalopods also surprise scientists with their amazing senses of touch, taste and smell. When they catch fish, they can tear it apart with their radula and beak (part of their mouth) and they can even sense gravity, which they use to coordinate muscle movements. Squid have eight arms and two tentacles. Both arms and tentacles have suction cups on them, and squid will shoot their tentacles out into the water and capture prey.

LINKS:

http://norb.homedns.org/nwp/storycode/mrj-web/large-5.html

http://norb.homedns.org/nwp/storycode/mrj-web/large-6.html

*** This post is dedicated to Geology Byotch, who not only gave me the idea for both posts, but also inspires me, teaches me and has, in my mind, become a good friend. Blessings, my dear.