Cuttlefish

Cuttlefish have some of the most incredible camouflage of anything in the animal kingdom. Their highly complex brain allows them to control the cells in their skin to blend in perfectly with their surroundings, or flash colorful displays much like an LED billboard.

The cells on the skin of a cuttlefish are covered in tiny dots of all colors, much like the tiny dots that make up the screen of your computer. A cuttlefish can make their cells grow or shrink to bring out the perfect blend of colors to match whatever is around it.

Its skin can also change shape from its usual smooth texture to whatever matches its surroundings. When it combines its color and texture adaptation, a cuttlefish can become nearly invisible even in plain sight. Because it can change its camouflage almost instantly, cuttlefish are very good at stalking prey, or avoiding becoming a meal themselves.

Cuttlefish are excellent predators, feeding on small fish and crustaceans. They will sneak up on their prey until they are close enough to strike, then shoot out two of their longest tentacles like harpoons to grab onto their prey with their suction cups. Then they reel their victim back into their mouth. Cuttlefish will also sometimes flash waving patterns of bright colors to confuse their prey while they move in for the kill.

Cuttlefish are not actually fish as their name implies. They are mollusks, close relatives of octopus and squid. Unlike their boneless cousins, cuttlefish have an internal shell which acts a skeleton to help them hold their shape. Cuttlefish shells are often sold at pet stores as calcium supplements for birds.

Cuttlefish use their skin for more than just camouflage. They can also use their amazing control of color to communicate. They often change to bright colors when they are angry to warn other sea creatures or other cuttlefish to stay away. They also use their arms to communicate, holding them in certain positions as if they are using sign language.

I once found a cuttlefish while I was snorkeling in Cozumel. Unlike most marine life, it seemed genuinely curious about me. I swam in close and moved my fingers into the position it had its tentacles in. It waved its arms back and flashed bright colors at me as if it was trying to carry on a conversation. After a few minutes, the cuttlefish darted away and disappeared. I still wonder if I said something mean or just wasn't much fun to talk to.

Cone Snail Videos

I was happy to see how much attention the post on Cone Snails has gotten. I understand it is hard to picture a snail killing something, so I dug up a couple of videos of these slow but deadly predators on the hunt. It's somewhat disturbing and totally amazing to see these Cone Snails in action.

This is a very good clip from National Geographic showing the full process of a Cone Snail hunting.



And this video from Nature shows how quickly a Cone Snail can subdue a live and very active fish.



One of the reader responses to my previous Cone Snail post asked where Cone Snails can be located. I found a map from National Geographic showing just this.

It's small but you can see the regions where Cone Snails can be found highlighted in yellow. They are mostly located in tropical oceans. Florida is the only place in America that I know of where you can find Cone Snails. Still, if you think you might have found a cone snail, just remember the general rule of the ocean:
When in doubt, don't touch it.

Cone Snails: Deadly Predators

Oddly enough one of the most deadly animals in the entire ocean is a tiny snail called a cone snail. While it seems comical to even think of a snail as dangerous, let alone lethal, cone snails have some of the most sophisticated and deadly neurotoxins known to man. A cone snail sting can kill a person within minutes of injection.

While most snails simply graze on algae, cone snails are active predators. They are fully capable of catching and eating quick and agile fish. These mollusks move just as slowly as other snails, but they pack a hidden weapon. They have a long tube which conceals a deadly harpoon tipped with their powerful venom. They can fire this harpoon with lightning fast accuracy. Their prey is killed almost before even knowing it has been hit. The snail then reels the dead fish into its vacuum-like mouth and swallows it whole.

People are rarely attacked by cone-snails because they do not actively hunt humans. Only about 15 known cone snail related deaths have been reported to date. Most of these incidents occur because people pick up the beautiful shells they see on the ocean floor. When the snail is agitated, it fires its harpoon, and the person often dies within minutes. If you ever see a cone-shaped shell lying on the sand, it's best to just leave it alone.

Sea Slugs Part 3

Yes, I have even more amazing sea slug photos. There are so many diverse and unique species of sea slugs. These are just a few of the most colorful.

Sea Slugs Part 2

I found so many amazing photos of sea slugs that I needed a second post to fit them all. It never ceases to amaze me how colorful some sea creatures are. I guess if and animal is poisonous enough, it can afford to be flashy.

Sea Slugs

Nudibranchs, commonly referred to as sea slugs, are some of the most beautiful creatures in the ocean. They are shell-less mollusks related to octopus and clams.

They can be found in oceans throughout the globe, most commonly in shallow tropical waters.

Sea slugs eat a variety of foods, and are usually carnivores. Many species feed on sponges. Some are cannibals.

Sea slugs are often very brightly colored to warn predators that they pack deadly poisons. This kind of coloration advertises that they are bad to eat and keeps predators from trying to make snacks out of them.

Sea slugs are some of the few animals that carry both male and female reproductive organs. They can effectively breed with any other member of their species.

Octopus

One of my favorite sea creatures is the octopus. Most people know of them as eight-legged sea creatures, but few know just how fascinating they really are. They are actually very intelligent, perhaps the most intelligent invertebrates in the world. They have been known to learn and solve problems in research laboratories. They have many unique adaptations that allow them to thrive in just about any part of the ocean. They are skilled predators and crafty survivors.


These creatures are mollusks, related to clams, sea shells, and squid. They have a hydroskeleton, which means they are held up by water. They have no bones, and become a limp blob when out of the water. Strangely enough, this doesn't always deter them from slithering up onto land to get to food trapped in tidepools. They can squeeze their bodies into tiny crevices and through holes just a tiny fraction of their size.


They have a large number of defense mechanisms to ward off predators. They camouflage perfectly with their environment and become very hard to see. Their skin is covered in cells that allow them to change colors to match nearly any surrounding. The skin of many species can even change shape to mimic the textures of the world around them. If a predator does spot an octopus, they can spray dark ink into the water. This smokescreen shrouds them from view and allows them to jet away quickly.


Octopus normally crawl along the ocean floor on their eight legs. When necessary, they can force water through their body and out in a strong jet to propel them quickly backwards. It is much like when you let the air out of a balloon. Their legs are covered in suction cups which allow them to stick to surfaces, pick up objects, and hold onto prey. They are fierce and stealthy predators and will pounce on unsuspecting crabs and other small creatures they can catch. There are many interesting species of octopus which I will highlight in later posts.

Giant Squid

Sailors used to tell stories of the Kraken, a great sea monster with long tentacles which could swallow ships whole. It is believed this mythical beast was inspired by the real monsters in the ocean, the giant squid. This creature has been a mystery to science until very recently. The largest giant squid on record is over 60 feet long. It is by far the largest invertebrate in the world, and the biggest mollusk in the ocean.

Giant squid are very elusive and live in such deep water it is almost impossible to seek them out. Scientists knew these squid must be real because they found giant suction cup scars on Sperm-Whales that were known to feed on these giant mollusks. Giant tentacles were then found in the belly of dead Sperm-Whales, and then some bodies of giant squid were found washed up on the beach. But for centuries no living specimens were found, until 2004.

The photo above was taken by a Japanese research team that captured the first live giant squid on record. It was said to have put up quite a fight, but the team finally caught it and pulled it on board. It died while being captured, but its body was measured at 24 feet long. This was not a fully grown specimen. Giant squid are commonly known to grow over twice that size.