Snake With Taste For Escargot Evolves Bizarre Strategy

[Ishbir 0]

If the French had teeth like the Iwasaki snail-eating snake, they wouldn't need tongs and tiny forks to eat escargot. The Japanese snake, Pareas iwasakii, preys mostly on snails and slugs, but its jaws are too weak to crush snail shells. Instead, it uses pin-sharp teeth to grab a snail's body and tug it from its shell. Most snails have shells that swirl to the right in a clockwise direction. So the snake has evolved an upper jaw with more teeth on the right side than the left.

 

 

A new study finds that the lopsided-jaw design helps the snake extract and scarf down its slimy meal.

 

Researchers led by Masaki Hoso at Kyoto University filmed four Iwasaki snakes feeding on snails with either left- or right-swirling shells. Videos show the snakes sneaking up on a snail, grabbing it by its foot, and then yanking it out of its shell with alternate retractions of their left and right jaws, a movement that some researchers call "mandible walking."

 

They found that snakes took a longer time and required more jaw retractions to extract the soft bodies of snails with left-swirling shells.

 

The study, to be detailed in an upcoming issue of the journal Biology Letters, reveals how this toothy adaptation opened up a unique menu for some snakes.

 

"Our results demonstrate that symmetry break in dentition is a key innovation that has opened a unique ecological niche for snake predators," the researchers write.

 

In a sample of 28 snakes, the researchers found each one had an average of 17.5 teeth on its left jaw and 24.9 teeth on the right. The asymmetry was present even in unhatched snakes, suggesting the trait is genetically determined.

 

The results also confirm the defensive benefits of a left-swirling, or sinistral, shell for snails. A separate study recently found that crabs that preyed on snails had a tougher time with left-swirling snails.

 

"The remarkable diversity of sinistral snails in Southeast Asia may be attributable to 'right-handed predation' by snakes," the researchers wrote.

[Grafitti 0]

How do we know they evolved that jaw? do we see early Iwasaki snakes with regular jaws? What if they always had that special jaw, because they always ate snails. Let's put some into a test where they're only fed snails with left-swirling shells, and see how long it takes for their jaws to reverse.

[brcmville 0]

How do we know they evolved that jaw? do we see early Iwasaki snakes with regular jaws? What if they always had that special jaw, because they always ate snails. Let's put some into a test where they're only fed snails with left-swirling shells, and see how long it takes for their jaws to reverse.

I am sure you know that we would not be getting any conclusive results for a very, very long time. Possibly in the thousands of years. Our planet is billions of years old, giving many thousands of years of time for animals to "evolve" the best characteristics for the environment they live in. I find this study pretty interesting because if something like this occurred in Humans, like say a right arm that was naturally bigger then the left arm or with one or more bones, the entire course of human history may have been different. Wars would have been fought with the idea that the right arm was dominant and military tactics would have been amazingly different.

 

Symmetry is a good thing to have though, with more benefits in the long run. If the Iwasaki snail-eating snake had a symmetrical arrangement of teeth, eating snails with a left and right swirling shell would be equally difficult to do, allowing the snake more options.

 

On a side note, I have a very pronounced fear of snakes. When watching the movie Snakes on a Plane, I probably lost 5 pounds from sweat. (Possibly less:P). Looking at pictures like this is pretty interesting though, and I am glad that I read this article. It gives me one more fact to back up my supporting the theory of evolution

[beatgammit 0]

Personally, I believe in creation, but I also believe in evolution. I believe that all animals evolve to fit changing needs. Many of my friends do not believe in evolution, so I like to hear about new proof, or at least quite conclusive evidence, for evolutionary theory.Evolution takes a long, long time to occur, as it involves nature "choosing" traits; those animals who are better adapted to their environment will survive to reproduce, passing on genes to future generations. If these snakes were placed into an all left-swirl environment, the ones who were better adapted to that environment would survive to reproduce, those who did not might not survive. Over a couple generations, leanings toward the left-aligned teeth would begin to be noticed.This is very interesting, thank you for sharing.

[threesix 0]

i don't see why the stupid snakes don't just crack them like eggs instead of waiting for evolution i mean they are snakes and snakes are supposed to be smart .......... i think.

[Aniki 0]

Ah, new evidence of evolution. Not just that, another example of the complete insanity of Earth. Theists argue that this 'perfect' world couldn't possibly have been created from a random event. But our world isn't perfect... just look at this snake, or the platypus.Anyway, it is really an interesting snake... I need to look into that a bit more.