snail

Geography Cone Snail

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Various shells that used to belong to Geograph

Although you wouldn’t think it, these seemingly innocuous shells belong to one of the most dangerously venomous creatures on the planet, and they are called Geography Cone Snails. I saw the little shells at the Secret Cities of the Sea exhibition at the Natural History Museum amongst various (less dangerous) animals. These animals, named for the mountain-like patterns on their red-white shells, are the most venomous animals on Earth, capable of delivering a fatal sting through a barbed harpoon that is actually a modified tooth. There is no known cure for such a sting the only method of survival being to last until the venom in your blood wears off. Bizarrely, this predatory snail only hunts on small fish, which it stuns with a poison soup before spearing and ingesting through its proboscis. We can, for this reason, assume that the venomous barb is for mainly defensive purposes, since using this kind of poison on small fish would be the largest recorded case of overkill ever seen.

Around 10cm in length, not only is this snail hard to spot in passing, but it is also scarily common, found fairly regularly in reefs around the Red Sea and the east African coast. 0.001 mg of the venom used would be enough to kill half of the population if every person were given a dose of that size, and even 0.0002 mg can seriously paralyse someone. Ironically, the venom has recently been discovered to contain a type of insulin, previously unseen, that can also be used as a highly effective painkiller, several thousand times more powerful than morphine without any of the addictive side effects that normal morphine gives. The problem remains of how to produce large quantities of these proteins for public use. How do you milk a Geography Cone? Very carefully. The answer to this may lie in implanting bacteria with plasmids containing the appropriate DNA for this proteins production, similarly to the way that Factor 8 and human insulin are produced for hospitals. Research is on going.

While this creature is extremely interesting (the most venomous animal on Earth, after all) and actual cases of snail attacks are very low, I hope that I never run into one of these unseeming killers while it’s having a bad day.

Australian Trumpet

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The shell of a (deceased) Australian Trumpet.

One of the more eye-catching exhibits at the Secret Cities of the Sea exhibition at the Natural History Museum was this shell of the Australian Trumpet or Syrinx Aruanus. This spectacular shell belongs to the largest shelled mollusc in the world, and one of the biggest gastropods, extinct animals not included. Measuring in at around 90cm at its largest length and nearly 20kg in weight this monster is known mainly for its tremendous size and is often hunted both for the amazing shell and the flesh, which is edible and used for food and fish bait. The shell is typically a faded yellow colour, but on a living specimen a thin skin will cover the majority of the shell, making it look more of a brown muddy colour, much in the same way that land snails have greyish shells while alive, but empty shells soon become a magnolia colour. The proboscis, a sucking mouthpiece used by many invertebrate predators to drain fluids from their prey, is a full inch long and is used to catch its extremely large food.

Living, as the Trumpet’s name suggests, in the northern parts of Australia and areas above it such as southern Indonesia and much of Oceania, it is fairly common along the sandy sea bottom around 20-30m underwater. In some areas it is fished heavily and far less common, but generally it is a common animal and not unusual to see while diving. Using its large proboscis the Trumpet reaches under sandy banks and into rocky crevasse in search of gigantic tubular worms that can measure over a metre long, making the perfect enormous meal for another enormous predator. It will suck up its prey whole through its mouthpiece, rather than rasping against its food like non-predatory snails that we are used to in Britain.

This is a very interesting snail, and if I get the chance to go diving in the waters of Oceania (which would be truly amazing) I hope that I will have a chance to see this behemoth in the flesh.