cone snail , An amazing and poisonous snail

Cone snail, also know as snail, is an invertebrate of the family Conus of the order Neogastropoda. The shell of the cone snail is conical or biconical, solid, with a low spiral tower and large body whorls; the shell mouth is narrow and long; the shell surface has long veins, spiral veins, spiral grooves, particles and nodules on the shoulders, and presents various colors such as dots, cloud-like spots, axis and other shapes; the shell skin is thin or thick; the radula has only marginal teeth and a barb at the end; the shell surface is smooth. The cone snail is named because its shell is shaped like a chicken heart.

Cone snails are distributed along the coasts of China, Taiwan and the South China Sea Islands. They are also distributed along the coasts and islands of the Indian and Pacific Oceans. They often live on coastal coral reefs in the equatorial waters. Cone snails only come out at night. When hunting, they will ambush their bodies in the sand, leaving only their long noses exposed. The tip of the snail hides an opening that can shoot poison needles to instantly paralyze prey. Cone snails are carnivores that usually prey on worms, small fish and other mollusks in the sea. The breeding season is spring and summer. The egg sacs are bag-shaped and often attached to rocks. The female can lay 10-100 egg sacs at a time.

Toxins

Cone snails can inject toxins into their prey by contacting it, and the toxins can quickly invade the nervous system and kill the prey. The toxins of a cone snail can kill 10 adults. If you are stung by a cone snail, you will experience severe pain and ulceration of the injured part at the least; in severe cases, it will cause cardiac arrest and be life-threatening. Cone snail toxins are good chemical probes for studying ion channels and have been widely used as tool drugs, thus having dual-use value for military and civilian use.

History of Zoology

The cone snail, also known as the cone snail, is an invertebrate in the family Conidae of the order Neogastropoda. It is a general term for various cone snails. There are approximately 500 different cone snail species in the world. The cone snail is named after its shell, which is shaped like a chicken heart.

Morphological characteristics

The largest individual can grow to about 23 cm. The shell is conical or fusiform, solid, with a small, low spiral and a long, large body whorl. The opening is wider near the base than near the shoulder. The top of the shell is flat or has a protruding spiral. Some shells are smooth, while others have spiral decorations. The shell surface is yellow with various patterns and spots; the opening is long and narrow.

The shell surface has long veins, spiral veins, spiral grooves, grains and nodules on the shoulder, and presents various shapes such as dots, cloud-like spots, and axes in various colors; the shell is thin or thick; the radula has only marginal teeth and a barb at the end; the shell surface is smooth. The operculum is horny and small, and cannot cover the shell opening. The shell is thin at the front and thick at the back. The body is inverted cone shape, shaped like a chicken heart or taro.

Distribution area

It is a warm-water species that is commonly found near coral reefs in equatorial waters (more common in Brazil). Cone snail is distributed in tropical oceans, along the coasts and islands of the Indian and Pacific Oceans. It is also found in coral reefs along the coasts of China, Taiwan, and the South China Sea Islands , as well as along the coasts of Africa, Australia, New Zealand, the Philippines , and Japan.

Living habits

The cone snail is a beautiful snail that lives on coastal coral reefs and beaches . The cone snail only comes out at night. When hunting, it will hide its body in the sand, with only its long nose exposed. This not only allows it to obtain oxygen , but also allows it to monitor the movements of its prey. Its tip hides a small opening from which a poisonous needle, scientifically called a “harpoon”, can be shot out, which is enough to kill the victim.

The cone snail has a flexible “hypodermic syringe” connected to a sac filled with toxins in its body, which can quickly inject toxins into the body of its prey within a few seconds. Before being attacked by the cone snail, the fish relies on its biological nervous system to control its body. After the cone snail pierces the fish’s body with a needle, it stops the fish from struggling in less than a second. Then, the toxin launches the first round of attack, quickly entering the chemical valve that controls the fish’s nerve signals, keeping the valve open for a long time, and the toxins continue to invade the fish’s body.

Due to the effect of the cone snail’s toxin, the fish’s muscles began to spasm. Just before the fish managed to regain control of its movements, the cone snail attacked again. The toxin attacked the connection between the fish’s nerves and muscles, preventing the muscles from receiving commands. As the spasms became weaker and weaker, the fish was completely paralyzed. A series of marine venomous creatures such as cone snails have evolved a variety of physiological functions due to their long-term survival in a specific marine ecological environment. These physiological functions are reflected in their toxins. 

Feeding

This marine animal is carnivorous and usually feeds on marine worms, small fish, and even other mollusks. Since cone snails move quite slowly, they have to use their poisonous “harpoon” (known as a toxic radula) to catch fast-swimming prey like small fish.

The “harpoon” is formed by the improvement of its radula. For predators of mollusks, the radula serves as both a tongue and a tooth. The “harpoon” is hollow and sharp, connected to the root of the radula. When the cone snail finds prey approaching, it extends its long tubular beak toward the prey, and through muscle contraction, it shoots the “harpoon” filled with venom from the beak like a bullet into the prey. The venom can instantly paralyze the small fish, and then the cone snail retracts its radula and drags the subdued prey into its mouth.

Habitat

It often inhabits coral reefs, rocky and sandy seabeds in the intertidal and subtidal zones of equatorial waters.

Reproduction method

Eggs are usually laid in spring, and the breeding season is spring and summer. The egg capsule is sac-shaped and often attached to rocks. Each female can lay 10 to 100 egg capsules at a time. The egg sheath is flat and cup-shaped or bottle-shaped, and each sheath contains many eggs.

Main Value

There are many types of cone snails, and their shells have different colors and patterns, which can be used for viewing. Cone snail toxin is an excellent chemical probe for studying ion channels and has now been widely used as a tool drug, thus having dual-use value for both military and civilian purposes.

Species endangerment

Some cone snails have poison glands, so be careful when collecting them. Cone snail venom contains hundreds of different components, and the composition of the components varies greatly from species to species. These different toxins are called conotoxins, which include different peptides that target specific nerve pathways or receptors. The toxins also contain analgesics, which can cause prey to become immobilized and very calm before death. Some cone snails also contain tetrodotoxin , the same neuroparalytic toxin found in pufferfish , which is also found in pufferfish and blue-ringed octopuses .

The bright colors and color patterns on the surface of cone snails make it easy for curious people to pick them up, and this is exactly where tragedy occurs. Another type of cone snail is often call a “cigar snail,” meaning that after being stung by it. You usually only have time to smoke a cigar to save it.

Cone snails can inject toxins into their prey by contacting it. The toxins can quickly invade the nervous system and kill the prey. The toxins of a single cone snail can kill 10 adults. If a cone snail stings you, it can cause severe pain and ulceration of the injured part, or even cause cardiac arrest, which can be life-threatening. Its toxins are usually target at small fish. Since humans and fish have similar nervous systems, humans are also susceptible to cone snails. Tests have shown that victims of cone snails do not feel any pain before they die. Scientists have found more than 100 compounds in cone snail toxins, including compounds that block the transmission of information by the nervous system.