Sex
Throughout the breeding season, male and female Chinese yellow-headed box turtles (Kinosternon galbinifrons) engage in a complex sequence of behaviors and interactions known as mating. The mating process in this species typically consists of a few similar phases, however the exact behaviors could differ across groups and individuals.
In order for Kinosternon galbinifrons to successfully mate, they engage in elaborate courtship rituals. In order to entice female turtles, male turtles would often put on spectacular shows. Head bobbing, chin stroking, and circling the female are all examples of this behavior. These actions help in mate identification, determine the female's receptivity, and establish dominance.
Another typical action seen during courting is scent marking. Potential mating partners may learn of a male turtle's location and reproductive state via the production of pheromones or smell signals. Scent marking is a useful tool for females to find and evaluate potential mating mates.
After the wooing rituals are over and the turtles are both ready to mate, the mating process begins with mounting and continues with copulation. Coming up from behind, the male turtle clambers up onto the female and uses his forelimbs to grip onto her shell or limbs.
This arrangement makes it easier for the male to deposit his sperm into the female by bringing their cloacal apertures into close proximity to one another. Depending on the people engaged, copulation may last anywhere from a few minutes to a few hours.
Like the vast majority of turtle species, Chinese yellow-headed box turtles use internal fertilization. The cloaca is a shared orifice for reproductive and excretory processes across sexes, and it is here that the male deposits his sperm during copulation. After fertilization, the eggs are usually released from the mother soon after the sperm have traveled through her reproductive canal.
After mating, female turtles begin to display nesting behavior in order to get ready to deposit eggs. Part of this process can include looking for places to lay eggs, which are usually near bodies of water and have soil that drains well. The mother bird uses her hind legs to create a nest chamber once she has located an appropriate spot to lay her eggs.
After the nest is dug, the mother bird lays her eggs one by one, usually in a clutch of a few dozen to several hundred, depending on the species and the weather. The mother takes great care to insulate her eggs from predators and keep the humidity just right by covering each one with dirt and other detritus after laying it.
The next step, incubation, is for the eggs to be warmed by the soil and other environmental factors inside the nest cavity. This process begins after the eggs are deposited. The incubation time may be anything from a few weeks to a few months, however it can be much longer or shorter depending on environmental conditions like temperature and humidity. The little turtles leave the nest as soon as the eggs hatch and make their way to the ocean to begin their life on their own.