Saturday, April 17, 2010

A flawed gem

Luria lurida (Linn., 1758) is a common snail from the family Cypraeidae found in shallow Maltese waters. The specimen above was very timid and did not emerge from its shell fully, even after 30 minutes of waiting on my part. However, the tip of the siphon can be seen on the right hand side, together with a very small part of the mantle covering the shell's edge.

Gastropods happen to be a favourite food of their far more cunning relative, the octopus. An octopus can usually pull other snails right out of their shell, but L. lurida has a narrow aperture and is well-protected in this regard. Besides, it withdraws deeply into its shell, beyond significant reach of the octopus' tentacles. The octopus therefore resorts to drilling a hole in the shell with its tongue, enabling it to secrete enzymes and extract the animal (Wodinsky, 1969).

Such drill-holes are commonly found on beached L. lurida, as can be seen in the photograph below.

Wodinsky, J., 1969. Penetration of the shell and feeding on gastropods by Octopus. American Zoologist, 9 (3): 997-1010.


  1. Hi David Cillia,
    Does Malta has any scuba diving sites? Did you see the octopus attacking such cowries in the wild?

  2. Hello! As for scuba, Malta is a great place for such an activity and also very well-known in this regard. Unfortunately I've only been snorkelling so far, though I intend to start soon.

    Regarding the octopus - I've never seen one actually preying on the cowries, however, penetrated cowry shells are common at octopus hide-outs and actually alert divers to the presence of octopi nearby, together with many empty Haliotis shells and crab carapaces, all these being favourite octopus foods.


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