Kauri Snail – Pupurangi

Paryphanta busbyi

Kauri snails are a beautiful bronze, carnivorous snail

Kauri Snails belong to the oldest family of land snails on earth, dating back 200 million years.

Kauri snails are found around the Tangihua lodge

The photo opposite is of a Kauri Snail who lives beside the Lodge and is sometime seen hunting along the edge of the bush or out on the grass at night. Based on its size, this particular snail is around 10 years old.

Kauri Snails have a hard, stripy bronzy coloured shell and a black body. Their shells have the spiral shape like regular garden snails but tend to be flatter, rather than rounded. Kauri Snails can live for at least 20 years and in that time they can grow a shell of up to 79mm in diameter.

Kauri Snail behaviour and diet

Kauri Snails are hunters as they are carnivorous, feeding on earthworms, insects, slugs and snails including other Kauri Snails, making them cannibals (see below)

Kauri Snails are nocturnal, hiding under forest debris during the day and coming out at night. They are highly mobile for snails, moving up to 10m a night. They stalk their prey slurping up earthworms like spaghetti or using their 100 rows of teeth to chomp up insects.

Kauri snail prefer earth worms and New Zealand has some of the biggest worms in the world. A native bush worm around 300mm long that was found near the Tangihua Lions Lodge, is a perfect meal for a Kauri Snail. For more information about Native bush worms click on the link

Video provided by by Kerry Weston, Department of Conservation

Kauri snail reproduction

Opposite are two Kauri snails found by the lodge who have been mating. The male is probably the one curled up in its shell asleep!

Kauri Snail mating can last for 10 hours or more and appears to be triggered by climate conditions such as rainfall.

They lay 10 to 12 eggs in nests on the forest floor beneath leaf mould, usually at the base of large trees. Each egg has a hard shell and is around 13mm long.

Once they have hatched the hatchlings climb up to 6m high into trees or shrubs. No one is quite sure how long they remain above the ground before venturing back on to the forest floor.

Kauri Snail distribution and Habitat

The favourite habitat of Kauri Snails is forests with lots of large trees, fertile soil, and lots of leaf humus. This habitat provides them with the damp conditions they need, lots of places to hide and plenty of insects and worms to eat.

As the name suggests, Kauri Snails are only found in the Kauri Forests in Northland and just north of Auckland. Contrary to the name, they don’t like to live under Kauri trees. The Kauri trees suck all the nutrients out of the soil and the leaves they drop don’t compost so the area beneath a Kauri tree isn’t the type of environment that worms and insects like and is therefore also not suited to Kauri Snails looking for food.

Threats and Conservation Plan

Kauri Snails, once common,abd widespread through out Northland are becoming rare and difficult to find.

Habitat destruction

Human settlement particularly land clearance altered or destroyed a large portion of their habitat.

Predation

Kauri Snails, once common, are becoming rare and difficult to find. As you walk the tracks around the Tangihua Lions Lodge you will find empty and broken shells. This is a result of introduced predators such as possums, rats and pigs feeding on the defenceless snails.

Protecting a Kauri snail habitat

The Tangihua Forest is an ideal habitat for Kauri Snails except for introduced predators who a decimating the population. For Kauri Snails to survive and thrive we must remove or reduce the numbers of predators.

The Tangihua forest block is managed by the Department of Conservation (DOC). They currently do not have the funding available to put in place the strategies needed to eradicate pests and protect the forest.

• We will identify 40ha that has a good habitation and existing population of Kauri snails.
• We will then put in place a very high level of pest control targeting pigs, rats and possums.

This will be around or close to the lodge. The bait stations and traps are in place

Our other projects

The Tangihua Lions Lodge has set up the following programs that you can be a part of;

Tangihua Community Pest Control Area: Targeting pests on farm land with local farmers and the Northland Regional Council

Conservation on DOC Land: Tangihua Lions Lodge Conservation and Education project

Conservation Education: Creating a high quality, accessible educational center surrounded by a fully functional ecosystem for schools and any one else who may choose to use the facility.

Volunteers Options : How you can help protect our native bush.

For Kauri snail to survive we must remove or reduce the numbers of predators such as rats, possums and pigs

We are going to do this by setting up a conservation program that will include bait stations for rats, possum, traps for cats and mustelids. Local pig hunters will take care of the pigs.

References

It is very apparent that specific information has been shared online between many organisations. Attributing to the initial source is impossible. As much as possible we have used our own photo’s and the following websites have been used as sources for our information;

• Te Ara The Encyclopaedia of New Zealand
• Wikipedia
• DOC website
• T.E.R:R.A.I.N Taranaki Educational Resource: Research Analysis and Information Network