Sex

The tortoise mating process starts with courting rituals, in which the male and female perform a set of behaviors designed to entice and evaluate possible mates. Tortoises' vocalizations and activity levels may spike during mating season. Males may make low-frequency noises or put on a show by circling, prodding the female with their chins or forelimbs, or bobbing their heads. In order to establish dominance or compatibility between individuals and indicate the male's intentions, certain courting displays are used.

One courting practice that certain tortoises, like Alamos mud turtles, use is scent marking. To entice females and signify that they are ready to reproduce, men may emit pheromones or chemical signals. Scent signals may help female tortoises choose a partner and determine if they are a good fit for mating.

Following the completion of wooing rituals and the establishment of mating couples, the mating process usually involves mounting and copulation. Tortoises position themselves for copulation by mounting the female from behind and using their forelimbs to hold onto her shell or hind legs. To successfully inseminate a female during copulation, the male may make rhythmic motions with his tail or rear limbs.

Tortoises are oviparous, meaning they lay eggs instead of having live babies, which is an internal fertilisation process. During copulation, the male fertilizes the eggs by transferring sperm to the female's reproductive canal. When a female tortoise is ready to lay eggs, she uses her oviducts and ovaries to do so. The eggs are then transferred to the cloaca.

The female tortoise begins to display nesting behavior after mating in order to get ready to lay her eggs. In order to lay their eggs, they may use their hind limbs to excavate a small depression or burrow in the substrate. Because of their potential impact on egg development and survival, nesting locations are selectively selected according to criteria including temperature, humidity, and substrate composition.

After the nest is ready, the female tortoise deposits her eggs one by one, creating a clutch that may include anywhere from a few dozen to several hundred eggs, depending on the species. To insulate and protect her eggs as they incubate, the mother may use her hind legs to delicately place and cover them with substrate. In order to keep her eggs safe from predators, the mother may add more substrate or plants to the nest cavity after depositing them.

Once deposited, eggs mature and grow within the nest during a time known as incubation. Temperature, humidity, and species are among the variables that affect incubation durations, which typically fall within the range of a few weeks to a few months. When they are old enough, hatchlings use a particular tooth called an egg tooth to crack apart their eggshell and crawl out of their nest. Although certain species' eggs may get some parental care or defense from predators, in general, hatchlings are left to fend for themselves immediately after birth.