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.

Crabs

Crabs are Crustaceans and members of the Arthropod phylum. They have a hard exoskeleton surrounding their entire bodies which acts as a suit of armor. Most crabs use their powerful claws to fend off attacks and capture prey.

Some species such as the hermit crab scoot into empty snail shells and carry the shell on their backs. When threatened, they can disappear into the shell.

Other species rely on camouflage to hide from predators.

Most species of crabs can survive for short periods of time outside the water. Their shells hold enough water to keep their gills moist, therefore allowing them to breathe on land. Some crabs spend most of their lives on land.

Crabs range in size from barely visible to the giant coconut crab pictured here. Crabs can be found all over the world in a staggering variety of shapes and colors.

Mandarin Goby

One of my favorite fish in the whole ocean is the Mandarin Goby. Its lifestyle and behavior are much like any other goby, but its colors are absolutely stunning.

These vibrant and flashy fish can be found as the centerpiece of many saltwater aquariums. They are heavily sought after because of their beautiful display.

Dinoflagellates: Bioluminescent Algae

In some oceans when the night is dark enough, you can see the waves glow as the water stirs. This is caused by phytoplankton called dinoflagellates. They give off a soft blue glow when disturbed. The chemicals they use are similar to the ones causing lightning bugs to glow.


When a person swims through the algae, the motion gives off a glow all around them, looking like angel's wings. Boats and wave action can also cause ripples of light to cascade in their wake. This video was taken at a dock in Australia where this algae is plentiful. People throw water on it to cause it to glow in amazing patterns.

Sea Anemones

Sea anemones resemble flowers, but they are actually cnidarians, related to coral and jellyfish. They spend their lives rooted to surfaces using a big sticky foot. Their tentacles wave in the currents and catch any pieces of food or animals that pass by.

Sea anemones spend their larval stage as zooplankton floating in the currents. When they reach maturity, they settle on the sea bottom and anchor themselves.

The tentacles of a sea anemone are lined with tiny cells called nematocysts. These cells contain a microscopic spring loaded harpoon. When an unfortunate animal brushes by, the harpoon fires, ensnaring the victim and delivering deadly poison. Once the hapless victim is entangled, the anemone pulls it into its mouth. It digests the food in its stomach and excretes the waste back out through its mouth.
Sea anemones are often sought out as partners for other organisms which use their powerful poison as defense. Hermit crabs will often uproot small sea anemones and stick them on their backs. This serves the anemone well because it is now mobile and can more easily catch bits of food. It also gets to snack on any of the crab's leftovers. The crab benefits by having added protection from predators. Anything trying to eat the crab gets a powerful sting.

Another animal that uses the sea anemone as protection is the clown fish. These fish are adapted to keep the sea anemone from stinging them, and spend their entire lives nestled safely in their deadly tentacles.

Sea anemones come in many shapes, sizes, and colors, and can be found throughout the world, from the cold oceans of North America to tropical Australian coral reefs.

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.

Fish

When you think of creatures in the ocean, Fish are probably the first thing that comes to mind. Fish are some of the most populous and successful organisms in the ocean. They are fast, big, and perfectly suited for life in the sea. They are members of the phylum Chordata, meaning they have a backbone and spinal cord. Fish eat anything from algae and plankton to huge marine mammals.

Fish are some of the most diverse and populous organisms on our planet. Fish range in size from tiny fish we can barely see with our naked eye, to the giant whale shark, which dwarfs humans. Fish are spread throughout the oceans of our world and can be found in all seas except the Dead Sea (which is too salty to support any life). Fish can live anywhere from the hot tropical seas to the frigid arctic ocean. Fish have been found from the shallows of tide pools to the deepest reaches of the ocean humans have been able to explore.

I will cover some of the most beautiful, exotic, and bizarre species of fish over the course of this blog. Keep checking for more updates.

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.

Sponges

Sponges are from the phylum Porifera. They are some of the most simple animals in the ocean. They are huge colonies of cells without a central nervous system. They are really a huge group of individual cells built into a colorful and intricate structure. Sponges come in many different shapes and sizes, and they add splashes of color to a coral reef.

Sponges are full of holes and very porous. This is to allow water to pass through them. They are filter feeders, meaning they pull tiny plankton out of the water and eat the microscopic bits of food that flow in the current. They have tiny hairs that wave in the water, pushing water past them and allowing them to grab bits of passing food. They serve to help keep the water clean.

The household sponges we use today were designed after sea sponges. There used to be a major industry for harvesting sea sponges for use in household cleaning. Because of its destructive effects on the marine habitat, this practice has been replaced by more environmentally friendly synthetic sponges.

Coral

Coral reefs are home to millions of fish and some of the most abundant and beautiful life on our planet. Coral reefs also provide a barrier to protect land from erosion and they can even form entire islands. Much of the sand found on many tropical beaches is actually coral, ground up and refined.

Coral may look like brightly colored rocks but they are actually living creatures that secrete a hard exoskeleton where they live. Colonies of thousands of tiny creatures cling together to build a coral head. These coral heads build on each other to make an entire coral reef where a myriad of life can thrive.

Coral are actually related to jellyfish and sea anemones. They are very delicate and can only live in certain conditions. They need clear, shallow water to allow plenty of sunlight to reach them. They also need very warm temperatures to thrive. This is why most coral reefs are only found in the tropics. The reason they need so much sunlight is because they actually have algae living in their cells. The coral provides the algae with shelter and safety, and the algae provides coral with energy. Coral also feeds on floating animal materials that it snags in its outstretched tentacles.