THE UNIVERSITY OF CHICAGO PRESS, OCTOBER 2012Reproduction is without a doubt one of the most delightful parts of being a vertebrate. Unlike arthropods, whose mating rituals can range from seemingly perverse acts culminating in the death of the male (think praying mantises and certain spiders) to traumatic rape and insemination (think bed bugs), for us more civilized backboned animals, mating is mostly an act of great pleasure following courtship and foreplay. Without sex and the subsequent mingling of two individuals’ genetic material, gene pool transformation would not occur. Sex is therefore central to evolutionary change.
The rise of this most pleasurable and evolutionarily productive of all vertebrate behaviors is the focus of my latest book, The Dawn of the Deed.
There are many strange and interesting ways in which living vertebrates reproduce. The oldest and likely most primitive method is displayed by fishes, which typically spawn gametes into water: females lay eggs and males fertilize them by shedding sperm over them.
But some fishes—in particular sharks, rays, and their kin (called chondrichthyans)—perform a kind of copulation, which is necessarily preceded by mating behaviors such as ritual courtship. In some species of whaler sharks (Carcharhinus sp.) the males bite the females’ pectoral fins to prepare the females for mating and to properly position themselves for the act of copulation. Following their ...
