These snails are carnivorous, eating mostly earthworms, although they’re also known to eat slugs. But what’s interesting about them is their rather peculiar table manners.
The Powelliphanta snail, endemic to New Zealand (represented by at least 20 species and 59 sub-species), feeds by sucking up its prey through its mouth in quite a gruesome spectacle. The largest species of this genus, Powelliphanta prouseorum, measures about 9cm across, weighs 90g, and can be found in Kahurangi National Park.
The snail has a tongue-like belt of teeth, called the radula, which it uses to scrape chunks of flesh into its oesophagus. Although it looks like the prey is being swallowed whole, it’s actually subjected to prolonged radulation – enveloped by the snail’s mouth and suffocated inside, the predator’s 6,000 teeth scraping, rasping, and boring into its flesh.
Powelliphanta snails are vulnerable to dehydration, so they cannot survive in dry conditions – therefore they are more common in the western parts of New Zealand, where forests are generally wetter.
Despite being a serious threat to an unsuspecting earthworm or slug, Powelliphanta snails have their own predators, and many species within the genus are in danger of extinction.
According to the New Zealand Department of Conservation, 34 taxa are in danger of extinction, and another 13 are endangered – mostly from predation, habitat loss and degradation, and climate change contributing to increasingly dry conditions.
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These snails are so rare that their extraordinary behaviour can only be filmed in captivity – like in this clip from BBC Earth, narrated by actor Sam Neill.
Top image: Powelliphanta lignaria johnstoni, Mōkihinui River. Credit: Chris Pugsley, CC BY 4.0, via Wikimedia Commons
