Question of the month

Snails hitting the bottle

An accumulation of land snail shells. Photo courtesy of Kathryn McConnochie.

I saw this cluster of shells in the bush on Fraser Island, and I was wondering why they are here and whether they can be identified?

Answer

These shells are from an unnamed species of camaenid snail. Photo courtesy of Kathryn McConnochie. A Noisy Pitta, hungering for snails. Photo copyright Queensland Museum, Bruce Cowell.

Accumulations of snail shells can be the work of several different animals, including rats and bowerbirds. However, the type of damage seen on these shells is the work of a Noisy Pitta (Pitta versicolor). These colourful birds collect snails in the forest and bring them to a preferred ‘anvil’ (usually a rock) on which to crack them open. They grasp the shell by the aperture (opening) and smash them against the anvil, until they break at their weakest point (the spire, thinnest part of the shell because it is the oldest, and was made when the snail was much smaller). The Pitta then sucks the flesh from the shell.

Curiously, this Pitta has been using a glass bottle as an anvil. Fraser Island is a sand island, and has few stones that would make a suitable anvil. The discarded bottle is thus a boon for the Pitta, and doom for the snails.

The shells in the photos are from a species of land snail in the family Camaenidae. However, I can’t tell you its name, because it doesn’t have one! Land snails are massively diverse in Queensland, and many species still await formal naming and classification. Naming a new species is often a slow process, requiring specialised training. The scientific process of naming a species is called taxonomy, and scientists who specialise in naming species are called taxonomists. Due to the immense biodiversity of our planet, no taxonomist can know all the named species, so taxonomists tend to specialise on smaller groups (e.g., flies, ascidians, etc). Queensland Museum honorary research fellow Dr John Stanisic is Australia’s leading expert in land snails, and has named more than 300 species. Naming this new species is a focus of Dr Stanisic’s current research.

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