It's the Milky Bar snail - a giant carnivorous albino Powelliphanta found living in New Zealand bush.



A group of trampers stumbled across the rare find - only the second recorded - during a trip though the Kahurangi National Park at the tip of the South Island.



"Our group had seen three or four snails already that morning as it had rained and they'd come out in the wet conditions," said tramper Bill Brough, of Motueka.



"Then I saw the white snail and went wow! We were excited to see it, knowing how extraordinary it was."



Powelliphanta snails are found only in New Zealand and are the giants of the snail world. They are carnivores, with their favourite prey being earthworms. They also eat slugs.



Photos taken by the Waimea Tramping Club show the Powelliphanta hochstetteri hochstetteri had a characteristic golden brown-spiralled shell but a body that was glowing white rather than the usual deep black colour.



Department of Conservation Powelliphanta expert Kath Walker says in more than 30 years studying the native snails it is only the second albino she has seen.



The first was 23 years ago in 1988, when a Powelliphanta gilliesi gilliesi snail was found at Mt Burnett in Golden Bay.



However, that gilliesi snail was only partially albino. It had dark internal patterning still visible on its otherwise white body and, like the recent find, still had a normally-coloured shell.



Brough said no patterning was apparent on the Powelliphanta hochstetteri hochstetteri he saw.



He describe the snail as "off-white, like Milky Bar white chocolate" in colour.



Waker said albinism was known to occur in many animal species around the world.



The absence in pigment, which could be partial or complete, was due to a genetically-inherited defect in the enzyme which produced melanin.



She has since searched the spot where the latest white Powelliphanta was seen but was unable to find it.



"I was curious and interested to see the albino snail as it is exceptional to come across one," Walker said.



"From the photos it looks to be an adult snail at least 10 years old and I am amazed it has survived this long. Its white body would make it clearly stand out to be picked off by weka or other predators."



Earlier this month it emerged the Department of Conservation accident froze 800 Powelliphanta Augustus snails to death after taking them from the Stockton plateau on the West Coast for protection.



SNAIL FACTS



*Powelliphanta snails, found only in New Zealand, are the giants of the snail world with striking spiralled shells in an array of colours and patterns. They are carnivores, their favourite prey being earthworms. They also eat slugs.



*These snails live among the leaf litter on the forest floor from which they emerge in cool, wet weather. Shells are more often seen than snails out of their shells which are only spotted infrequently.



*The white snail is a brown-based Powelliphanta hochstetteri hochstetteri which grows up to 80 mm across. It is found on the Arthur and Lockett Ranges. A yellow-based form of the species lives north of Takaka Hill.



*The species is endangered due to predation by introduced pests: possums, rats, pigs and thrushes. DOC carries out possum control in the area primarily to protect the snails. The Friends of Flora community group also carries out pest control over around 5500 hectares in that part of the park to enhance the native vegetation and wildlife.

BLACK AND WHITE: A typical example of the same species.