Snails with shells coiling to the left survive snake attacks (w/ Video)

Snails with shells coiling to the left survive snake attacks (w/ Video)
Mating between sinistral and dextral snails is almost impossible because their genitals are on opposite sides of their bodies. In the large Satsuma snails, for example, mating takes place face-to-face. All snails have both male and female reproductive organs, and when both snails are dextral or both are sinistral, everything lines up nicely. When one is dextral and the other is sinistral the genitals line up male-male and female-female.

Dextral snails are far more common than sinistral snails, and therefore have far more mating opportunities. This and the difficulty in mating means sinistral snails should become extinct unless sinistrality has some unknown advantage. Now, scientists in Japan and Taiwan have discovered the advantage is a resistance to snake predation.