Reptile Reproduction

Most reptiles reproduce oviparously, laying eggs that hatch outside the female’s body. A few, like the popular blue-tongue skink (Zootoca vivipara), are viviparous and give birth to live young.

파충류샵

To copulate, males release semen from their cloaca and it travels to an opening adjacent to each of the ovarian tubes. Once the sperm find an ovary, fertilization occurs.

Sexual Intercourse

Reptiles reproduce in two different ways. Males of some reptiles have a penis (such as turtles and crocodiles) while others, such as lizards and snakes, have two hemipenes (which look somewhat like the male genitalia in mammals). Regardless of whether they have one or the other, the purpose is the same: deposition of sperm inside the female’s body.

This usually takes place via cloa 파충류샵 cal apposition, where the male positions his cloaca close to that of the female, allowing her to receive the sperm. Another technique is the use of an intromittent organ. This is used by tuatara reptiles, where the male inserts his hemipenes into the female’s cloaca for sperm transfer.

Some reptiles use a technique called genotypic sex determination, in which the embryo’s sex is determined by its genes during a sensitive period in its development. Other reptiles, such as crocodiles and some lizards, have a temperature-dependent sex determination mechanism.

Temperature-dependent sex determination allows a single lizard or snake to produce offspring of both male and female sexes. It also allows for the occurrence of parthenogenesis, wherein the female can produce offspring without the aid of a male. This is possible because some sex hormones are produced during the sensitive period, and these can have opposite effects on an embryo’s sex. In addition, a certain amount of sperm may remain intact for years within the female.

Fertilization 파충류샵

Fertilization is the process that brings together an egg and sperm to form a new individual. In most animals, males produce sperm in their testes and then store them in the epididymis until they are released during sexual intercourse. Once they meet with an egg, the sperm are able to adhere to the egg through a protein known as fertilin. This binds to a protein called integrin in the egg plasma membrane and causes it to open up for sperm penetration. The egg then releases a zygote, which then undergoes cell division to become an individual.

Reptiles are almost all oviparous, meaning that they lay eggs instead of giving birth to live young. However, there are some lizard species that reproduce asexually and lay eggs without mating with males. They are able to do so by having cloacae that have both openings for waste, sperm and eggs.

In most snakes and lizards, the sex of the egg is determined by the chromosomes in the sperm at the time of fertilization. However, in most turtles and crocodilians, the sex of the egg is actually determined by the temperature of the eggs during a certain period of development after fertilization. Eggs incubated at a lower temperature will produce one sex, while those incubated at higher temperatures will produce the other (Bull 1980).

Strict parthenogenesis is seen in many fungi, bacteria and some plants, while incomplete forms of it occur in insects, amphibians and fish. This type of reproduction is also seen in the Central and South American electric ant, Wasmannia auropunctata, where fertilized eggs produce queens through automictic parthenogenesis with central fusion, which results in the separation of male and female gene pools.

Eggs

A reptile’s ability to lay eggs is vital to its success as a species. ‘Eggs’ can refer to two different biological structures: the female gamete that unites with the male to form a zygote, and the shelled structure that female oviparous reptiles deposit.

The hard outer shell protects the embryo from shock, harsh weather, and predators but is permeable enough to allow passage of oxygen and carbon dioxide. Inside the shell, there are protective extra-embryonic membranes (the amnion and the allantois) that serve to respire and store waste products, as well as a yolk sac that provides nourishment.

Most oviparous reptiles have internal fertilization. The process involves a male mounting the female and inserting his single penis or his two hemipenes into her cloaca. He then releases sperm into her body cavity so that it can be fertilized by the egg, producing a new offspring with his genes.

Some oviparous reptiles may also choose to retain their eggs in internal gestation until environmental conditions are favorable for offspring development. This is called ovoviviparity, and it has been observed in bearded dragons, blue-tongue skinks, some geckos, and turtles. Scientists have recently discovered evidence that the first amniotes developed extended embryo retention rather than a hard-shelled egg, and this may have played an important role in their successful evolution into viviparous reptiles.

Birth

Although most reptiles lay eggs, some reptile species give birth to live young. These are called viviparous reptiles. In viviparous reptiles, the female carries the unfertilized eggs inside her body until they are ready to hatch. This usually happens within days to months, depending on the temperature of the soil where the eggs are laid.

To reproduce, male reptiles deposit sperm into the female’s reproductive system through an opening in her body known as a cloaca. A cloaca is an organ that serves as the common opening of the reptile’s intestinal, urinary, and genital tracts. It can be apposed to the male’s penis (in turtles and tortoises, or crocodilians) or to the female’s hemipenes, which are retracted inside the body and appear as two bulges at the base of the tail in most reptiles (lizards, snakes).

The sperm find their way up one or both oviducts until they are above the glands that secrete the shell of the egg. Fertilization occurs once the sperm reach these glands, which may happen shortly after copulation, within an hour of ovulation, or even several weeks before ovulation.

Because reptiles don’t have external genitalia, it is difficult for pet owners to determine the sex of their reptiles. However, many sex characteristics can be used to distinguish between a male and a female, including the color of the head and body, the shape of the body, and the head size.