The flax snail is an amazing animal, growing up to 1.15 metres, an incredible size compared to the average garden snail most people are familiar with. There are three species of this large northern land snail: Placostylus found in the Three Kings Islands; Placostylus which is in Te Paki, and the eastern Northland snail species of Placostylus hongii. Prior to human settlement in New Zealand, these creatures were widespread but are now endangered or threatened.
The flax snail habitat is scrubland or broadleaf forest, and they usually make their home underground cover vegetation. Young flax snails live above ground though, on the leaves in the tree canopy and shrubs up to six metres above the ground. They only go to live on ground level when they have reached a suitable maturity and size. Their diet is herbivorous, including fallen leaves. Flax snails are endemic to New Zealand and are part of the world’s oldest land snail family. Their ancestors were in existence an amazing 200-300 million years ago.
Their life expectancy is up to 20 years and they reach maturity at three to five years. They seem to mate when the weather conditions are suitable, for example when it rains. Mating can apparently last for over 10 hours! They mate every year, except during times of drought. The shells of the flax snail are a beautiful coiled long brown shell and this may have proved to be one of the reasons for the flax snail’s endangered status. They were highly prized by collectors until shell collecting became illegal in 1982. The mammals introduced to New Zealand have also proved fatal to these snails like many other native animals. Rodents, possums, hedgehogs and pigs have all been unwelcome predators. Human settlement and land clearing as grazing by many of these introduced species has destroyed much of the flax snail’s habitat.
The Department of Conservation has recommended that landowners fence off the areas where there are giant snails to avoid livestock trampling on them. Pigs especially are to be controlled since they not only threaten the snail’s habitat but also eat the adult snails. Rodents, who threaten many of New Zealand’s native animals, also eat young flax snails. This concerted recovery programme has also replanted habitats conducive to the flax snail’s recovery, and as a result, some species of the snail have increased their populations from near extinction to colonies of hundreds.