Thursday, December 19, 2013

Snake Lips and Snails

Northern red-bellied snake -  Ryan Thies
I never thought of snake lips until I came across some studies while researching for the blog about slugs.  It turns out that when a few species come across a snail, they are real kissers.

Northern red-bellied snakes,  Storeria occipitomaculata occipitomaculata, eat slugs, snails and worms.  These soft bodied creatures are slippery prey.  To get a grip, they flare their lips which also may help them control the slime.  You could say they are real suckers for snails.  (Yeah, my editor groaned too.)

Ryan Thies
Midland brown snake - Ryan Thies
More studies have been done on the midland brown snake, Storeria dekayiwrightorum.
They feed primarily on earthworms, snails, slugs and soft bodied insects.  One study found that their diet was 75% slugs and 25% earthworms.  Needless to say, their preferred territory is marshes, swamps, floodplains and forests.

I find eating snails in a fancy restaurant to be a daunting task, associated with lots of red sauce on my shirt.  Remember, a snail is essentially a slug with a shell. Slugs have flexible slimy bodies, allowing them to escape predators.  They can squeeze through incredibly small holes in the ground and tiny crevices in tree bark.  The snail's defense is withdrawal into its shell, sometimes even having a little trap door to pull shut.  On the other hand, with its bulky shell, running away is not an option so anything with molars that can crunch them will have a tasty meal with their daily requirement of calcium roughage thrown in. 

Now snakes don't come equipped with molars, so how do red-bellied and brown snakes eat snails?  Tom Johnson describes in Amphibians and Reptiles of Missouri":

"Their flat head and elongated teeth enable them to grasp the soft part of a snail beyond its shell and hang on.  By pulling continuously and twisting its head and body, the snail eventually becomes fatigued and is extracted from its shell."
I will never think of snake's lips, not to be confused with the bluegrass song of the same name, the same way again.

Thanks to Ryan Theis for the pictures.  His extensive collection of Missouri herp photographs is at Ryan's Complete Herp Lifelist Page.

A list of some other snail predators is at haywardm.supanet.com

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