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.

Pistol Shrimp

Pistol Shrimps are tiny creatures with a deadly weapon. They are capable of shooting supersonic blasts from their fingertips with enough force to instantly stun or kill their prey.



You may notice that one claw of a pistol shrimp is much larger than the other, and very strangely shaped. This claw serves as both its lethal weapon, and its voice. This claw can be forcefully snapped shut, shooting a jet of water out at such a high speed that it actually vaporizes the water. This causes a small air bubble to form. The bubble collapses with enough force to send concussive shockwaves capable of stunning and incapacitating prey.

A pistol shrimp will lie in wait under a rock or in a burrow until food comes along. When it is in range, the shrimp will forcefully snap its oversize claw shut, shooting out sonic waves that incapacitate its prey. The helpless victim is dragged unconscious into the burrow and eaten by the pistol shrimp.

Another unusual thing about pistol shrimps is that they often allow a fish to live with them. Certain kinds of goby fish often share burrows with pistol shrimp. The fish serves as a guard dog, protecting the shrimp from bigger predators. In return, the pistol shrimp works hard to keep the burrow clean and excavate their home.

The loud blast created by a pistol shrimp's claw can be heard from great distances. Because of this, they also use their claw for communicating with other pistol shrimps. When you listen underwater you may hear a lot of popping sounds. Some of them may be made by pistol shrimps firing off their sound waves to communicate with each other.

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.

Jellyfish

Jellyfish are cnidarians, related to sea anemones and sea slugs. They consist of a dome-shaped body and tentacles that trail behind them. Jellyfish are able to swim through the water by pulsing their jelly-like bodies. Their tentacles are covered in poisonous stinging cells called nematocysts. These tentacles can paralyze or kill fish. Some jellyfish, like the box jellyfish below, are powerful enough to kill humans. The venom in a box jellyfish can stop a person's heart in less than 3 minutes.

While most jellyfish are relatively small, some can grow to enormous sizes.

During certain times of year, jellyfish can be found in huge numbers, clouding the seas with their pulsating forms.

Some jellyfish can even glow in the dark.