Dangers and Beauty of the Great Barrier Reef: The Cone Shell

The Great Barrier Reef is a beautiful and awesome sight and a great place to visit or vacation but beware of the sea, it holds many dangers. One such creature is the Cone Shell.

Cone Shells are numerous, comprised of about eighty species in Australia of which seven of these are dangerous to man and can be found in shallow and medium depths of the reef.

The ones that live out of the water on the sand, rocks or rubble have a layer called periostracum and covers over the multi-colored, hard outer surface of the shell. This makes it much easier for them to be camouflaged from other dangers in the reef. The underwater sand dwellers have very clean shells and the beautiful colors of their shells are clearly visible. These cone snails (as they are often called) are nocturnal, meaning they are active at sunset and just before sunrise.

The shells are speckled, with various colors and this can make them pretty enough, especially for unsuspecting children to pick up and this can be deadly.

The Cone Shells have very sharp teeth that have the capability of piercing right through clothing, so beware! Their venom is made up of several neurotoxic peptides that can and do result in death of humans.

The venom works by causing weakness, inability of coordination, blurred vision, and loss of speech and hearing. Severe cases could result in death by causing muscle paralysis or respiratory failure. Less severe cases just cause extreme nausea.

The best way to avoid a sting from a Cone Shell is not to touch a live one. It is not safe to touch the wide end because the extendable harpoon-wielding proboscis can reach most parts of the shell. Wear heavy shoes when walking through the waters of the Great Barrier Reef to protect your feet from harm. And please do not put the shells into pockets or sleeves!

The venom is in the saliva, which comes from two glands, each larger than the creatures brain. The same poisonous saliva that is present in toad or puffer fish is the same type that the Cone Shell uses to kill humans. You may not feel the bite right away, but very soon you will notice numbness around your mouth, followed by paralysis. Death results from respiratory failure!

Cones feed on worms, mollusks, and are know to be cannibalistic (meaning they feed on other cone shells).

To catch fish a snail needs fast acting venom and the cone shells definitely have that. They detect their prey from chemicals in the water drawn through its siphon. Then it extends it proboscis, (a hollow feeding tube) which has a hollow barbed tooth on the end with a poisonous sac attached.

The tooth is driven into the victim, and then poison is injected through the tooth. They can only use the tooth once but a supply of spare teeth is kept in a tooth sac and they are moved into position as needed. The cone holds victims by the tooth and releases poison into them and then draws it into the proboscis to be digested.

The cone shell carries a toxin concoction that is capable of killing humans and the venom from just one cone can kill (in theory) seven hundred people.

When you travel to the Great Barrier Reef enjoy yourself but you have been fore warned about one of the most deadly creatures that inhabit this beautiful place. Just be careful and you can have a wonderful and enjoyable time along with millions of others who have survived the dangers and beauty of the Great Barrier Reef.