Cone snails, also known as cone shells, or cones, are a large group of small- to large-sized extremely venomous predatory sea snails, marine gastropod molluscs. There are over 900 different species of cone snails and they are typically found in warm and tropical seas and oceans worldwide. They belong to the family Conidiae.
Until fairly recently, over 600 species of cone snails were all classified under one genus Conus, in the family Conidae. However, in recent years, it was suggested that cone snails should occupy only a subfamily that should be split into a very large number of genera.
These species have shells that are more or less conical in shape (hence their common name) and many species have colorful patterning on the shell surface. All cone snails are venomous and capable of “stinging” humans. They can even be fatal when handled live. However, cone snail venom is showing great promise as a source of new, medically important substances.
The larger snails, which are the most dangerous to humans, prey on small bottom-dwelling fish, while the smaller species mostly hunt and eat marine worms.
These snails are highly prized for the beauty of their shells, and for their potential medical purposes. Both of these reasons could result in the decline of the cone shell population but, as it stands today, cone shells are not currently endangered or threatened.
Cone Snail Characteristics
Cone snails are usually between 0.5 and 8.5 in (1.3 and 21.6 cm) in size and weigh around 3.5 oz (100 g). They are, as their name suggests, cone shaped, wide at one end and narrow at the base. At the wide end of the cone snail’s body, you will find spires or whorls of various heights. Some species have a shiny body while others have a dull or plain look.
The shells show a large variety of colors and patterns, and local varieties and color forms of the same species often occur. They are often brightly colored and have interesting patterns, although in some species the color patterns may be partially or completely hidden under an opaque layer of periostracum. Most cone shells have a background color of some variation of white, cream, pink or blue and are patterned in black, brown, orange or yellow, while some may be only one color.
There are radular teeth contained in the radular sac, and the size, number and design of these teeth varies by Conus species. The body mantle is thickened at the edge, and in one area a cavity for gills exists between the mantle and the body. The head has two tentacles, each with an eye about halfway down the outer surface. The foot is strong and muscular and may be colorful. The siphon is well developed and may also be colorful.
The cone snail has not been documented well and so it is difficult to know how long they live for. However, it is estimated hat these animals can live for between 10 and 20 years.
Cone snails are carnivorous. They eat marine worms, small fish, mollusks, and even other cone snails. They are very predatory animals and, although they are slow-moving, use a venomous harpoon-like tooth (called a toxoglossan radula) to capture faster-moving prey, such as fish. The venom of a few larger species, especially the piscivorous ones, is powerful enough to kill a human!
Cone snails are mostly active at night, although some will hunt at dusk and dawn, too. They are usually a solitary species, and will hunt and eat alone.
Reproduction in cone snails has not been widely studied. It is thought that fertilization is internal, and usually up to 5,000 eggs are laid. These egg capsules remain attached to the substrate before they’re ready to hatch and parents play no role in bringing up the baby cones. Two types of hatchlings have been described, the veligers (free-swimming larvae) and veliconcha (basically baby snails).
Cone Snail Location and Habitat
Cone snails are found in warm and tropical seas and oceans worldwide, including the Indian and Pacific Oceans, southern Australia, Great Barrier Reef, Hawaii, Baja California, and California.
They live in tropical and subtropical seas, from the intertidal zone to deeper areas, living on sand or among rocks or coral reefs. When living on sand, these snails bury themselves with only the siphon protruding from the surface. Many tropical cone snails live in or near coral reefs, under rocks in the lower intertidal and shallow subtidal zones and even among mangroves.
Cone Snail Conservation Status
Cone snails are often taken from their environment because of their interesting shells, which are then used to make necklaces and other jewelry out of. They are also collectables. Some countries have put restrictions on their collection.
Medical use of cone snail’s venom is another reason their numbers could decline in the future. Their are many different uses for the venom, including targeting particular receptors in the nervous system, and even as a source of insulin.
Fortunately, currently no species are listed as endangered or threatened although there is increasing concern among scientists that this may happen soon.
The biggest predators of cone snails are large fish. They use their venomous harpoon to help protect them from predators.
Cone Snail Venom
Cone snails are regarded as one of the most venomous species of snails out there. They use their venomous harpoon to sting and deposit venom inside their prey. The venom of cone snails contains hundreds of different compounds, and its exact composition varies widely from one species to another.
Humans often pick up these snails because of their bright colors and patterns. However, this can be dangerous, and harpoons of some of the larger species can penetrate gloves or wetsuits.
The sting of some of the smaller snails may be no worse than a bee sting or hornet sting, but the sting of some of the larger species can even cause fatalities. Symptoms and side effects of a serious cone snail sting include intense, localized pain, swelling, numbness and tingling and vomiting.
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