Garden snails Cornu aspersa

 

Garden snails Cornu aspersa mating.

One of the reasons garden snails are so successful is that they are hermaphrodite. In animals with separate sexes in equal numbers only half the population can produce eggs; in hermaphrodites like these snails every individual can lay eggs.

But they still need to mate, to exchange sperm, after a Cupid-like courtship ritual. Two individuals glide along side by side and fire calcareous love-darts into each-other, coated in a hormone which facilitates mating. and sperm exchange.