Hamish Tyson, of Port Chalmers, asks :-

What is the biggest type of snail in New Zealand?

Murray Efford, a Zoologist with Landcare Research, Dunedin, responded.

The flax snails or pupuharakeke Placostylus bollonsi that live on the Three Kings Islands in the far north have tall, narrow shells that can reach 11.5 cm.

Our largest native snail by weight has a suitably long scientific name: Powelliphanta superba prouseorum. Large specimens have shells that are up to 9 cm or even 10 cm across and may weigh 100 g. The species lives in northwest Nelson. Its eggs look like small birds' eggs, 14 mm long and 12 mm wide! Like many of our larger native snails, this one is carnivorous: it feeds on native worms. Oddly, some of its carnivorous close relatives Delos are only 2-3 mm across.

By world snail standards this isn't enormous: the Giant African Snail can be 15 cm long and weigh 300 g - quite a meal, although perhaps rather tough. It eats leaves, so perhaps our own Powelliphanta can claim to be the largest carnivorous snail in the world.

Our smallest land snails are only 1-2 mm across, but this is a murky area: many of these tiny crawlers don't even have names, yet.