Certain groups of Asian snails include both left-handed and right-handed species, with shells coiling to the left and right, respectively  Some left-handed species have evolved from right-handed ones  Also, researchers found that snaileating snakes in the same habitat have asymmetrical jaws, allowing them to grasp right-handed snail shells more easily  If these snakes ate more right-handed snails over time, this would have given left-handed snails an evolutionary advantage over right-handed snails, with the left handed snails eventually becoming a new species
Thus, the snakes' asymmetrical jaws probably helped drive the emergence of the left-handed snail species
Experiments show that the snail-eating snakes in this habitat fail more often in trying to eat left-handed snails than in trying to eat right-handed snails.