To court a female sea turtle, a male turtle will approach a female sea turtle and gently bite her neck and flippers. If she does not try to get away, the male climbs onto the female sea turtle’s back shell and holds on to it with the long, sharp claws of his front flippers. He hooks on to the edge of the female’s shell which often results in a scratched shell and bleeding wounds in the soft parts of her body. Mating can take place under the water or floating at the surface.
Both male and females’ reproductive organs are at the base of their tail, in their cloaca – an intestinal, urinary, and reproductive organ, all rolled up in one. Males have a very long tail and females have a short one, which is an easy way of telling the genders apart. The male’s penis is located in his cloaca. He reaches his tail underneath the posterior end of the female’s shell to reach her cloaca.
Mating can take many hours. Afterwards, the male will try to hang on to the female's shell to prevent other males from mating with her. Several males may compete for one female at the same time, aggressively biting the already mating male's tail and flippers to get him to let go of her.
Mating is challenging for a female sea turtle. She has to support male and her own weight and regularly swim to the surface for them to breathe. This is even more difficult when several males compete for her and she may have a risk of being drowned.
After the male and female separate, they mate again with other sea turtles. A female will mate with several males and store the sperm for several months until she is able to fertilize all of her eggs and start nesting.
A female sea turtle can lay several clutches of eggs in one season. The eggs are all fertilized by a variety of males, which contributes to the genetic diversity of the population. The females are very vulnerable when they come on land. They are not well adapted to for life out of water and therefore moves very slowly.
As she starts laying her eggs, she goes into a trance-like state. Once done, she covers the nest with sand. On average, a nest can contain anywhere between 70 and 125 eggs. She then goes back into the ocean and leaves the babies to fend for themselves.