Look away if you are an earthworm

Spotted on Lucas Brouwers’ Twitter feed (@lucasbrouwers), this great video of a Powelliphanta snail from New Zealand snarfing an earthworm. Keep your eye on the video – it all happens incredibly quickly! Odd thing to say about a snail, but true.

According to this PDF from the NZ Department of Conservation, Powelliphanta snails can grow up to 9 cm across and are nocturnal. They are also endangered, primarily because of human activity, although a recent survey suggested they were making a slight recovery. According to Wikipedia, “There are 21 species and 51 subspecies within the genus. The relationship between the species is complex, and it has been suggested that the group Powelliphanta gilliesi-traversi-hochstetteri-rossiana-lignaria-superba forms a ring species.”

There are other carnivorous snails on NZ, including the Rhytididae, which seem to be particularly vicious, according the NZ Dept of Conservation:

“They can eat other snails by biting their heads off and then they carry them to a quiet spot on the back of their foot where they insert their tails up into the prey’s shell. The tail secretes a liquid that slowly dissolves the prey’s flesh and the calcium from its shell. The Rhytida snail then absorbs the dissolved nutrients. It can take the snail several days to actually complete such a meal.”

One rhytidid snail, Wainuia urnula urnula, seems to use a similar rapid action to that seen in Powelliphanta and probably has the same basis. According to Murray Efford in The Journal of Molluscan Studies, “In the laboratory, W. urnula urnula captured landhoppers by rapidly everting the TVU-section odontophore beneath the prey and immediately drawing it into the mouth in a single action.”

So that’s how they (probably) do it. No sucking, just incredibly rapid movement, using that odontophore…

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