Reptiles are ectotherms and rely on external sources of heat to thermoregulate. Most reptiles are oviparous (laying eggs) but some like lizards and snakes are viviparous and give birth to live young.
Males have paired testicles and females have a cloaca without a true uterus. They are sexed by secondary sexual characteristics such as size, coloring and proportions of the head, tail and horns.
Fertilization
A multistep molecular process that takes place when highly specialized haploid gametes, called spermatozoa and ova (eggs) meet and fuse to form a fertilized egg, or zygote. It involves the migration of spermatozoa to the zona pellucida, the adhesion and penetration of sperm into the oocyte, and the fusion of the two pronuclei to create a single fertilized zygote.
Reptiles, including snakes, lizar 도마뱀분양 ds and turtles, have a very varied reproductive strategy that allows them to adapt to their different habitats. They can lay eggs, give birth to live young or reproduce asexually, depending on the species.
Most reptiles, including snakes and lizards, are oviparous, which means they lay eggs to reproduce. Female reptiles deposit their eggs in nests that they build or in the ground, where the eggs are protected until they hatch.
Male and female reptiles do not have external genitalia, so their mating is usually less public than that of mammals. However, the male reptile has a copulatory organ that consists of either a single penis (turtles and tortoises, order Testudines) or two hemipenes (lizards and snakes). During the mating process, the cloaca opens up to allow the discharge of semen. If the cloaca is in close alignment with the oviduct, the sperm will be deposited in her body cavity and fertilize her eggs. Otherwise, the sperm will be stored in a gonad until the next breeding cycle.
Ovulation
The ovaries of female reptiles are paired hollow, oval (or elongated) structures attached to the dorsal side of the body. These organs secrete steroid hormones, including estrogens and progestins. These steroids bind to three complementary classes of receptors on the uterus and surrounding structures. 도마뱀분양
Reptilian ovaries are capable of producing eggs in the oviparous species and are capable of storing sperm in some cases, as seen in the diamondback terrapin (Malaclemys terrapin). Asexual reproduction by males also occurs in six families of lizards.
Ovulation is typically initiated by the follicular maturation process. This involves the deposition of large amounts of yolk in the follicle. Once the follicles have matured, they are converted into secretory corpora lutea, which produce progesterone for a species-specific period of time. Luteolysis of these follicles is stimulated by prostaglandins.
Once a fertilized egg is formed, it is either passed out of the body or released in an aqueous environment. The latter is typical of the amniotes, or fully aquatic vertebrates. The amniotic egg is an important adaptation for fully terrestrial vertebrates, and it first appeared in reptiles.
Many reptilian patients with reproductive disease require surgical intervention. Surgical procedures include ovariectomy, ovariosalpingectomy, salpingotomy and orchiectomy. These procedures may be indicated in the presence of reproductive disease such as oophoritis, ovarioschisis, orchitis and paraphimosis. They are also indicated in cases of complications from reproductive activity, such as preovulatory follicular stasis and dystocia.
Gestation
Reptiles have different reproductive methods than mammals, such as laying eggs and giving birth to live young. Reptiles that lay eggs are oviparous, and this is what most people are familiar with when they think of reptiles. However, some reptiles, like the crocodile and the snake, don’t lay eggs at all but give birth to live offspring.
When a male and female reptile are ready to mate, they will produce hormones that cause them to become sexually receptive. After mating, the male will place sperm into the cloaca of the female reptile. The cloaca is the single opening at the base of the tail where waste, sperm and eggs leave or enter the body. Once the cloaca is fertilized, the female will lay her eggs.
The number of eggs laid varies by species, as does the time it takes for the eggs to hatch. The eggs are surrounded by amniotic fluid, which protects the embryo and provides oxygen while it grows. The embryo also has a shell, which protects it from predators and the elements.
Many reptiles lay their eggs in a nest. This may be on the ground, in a burrow or in the sea. Some reptiles, such as pythons and mud snakes, will protect their eggs by wrapping their tails around them. Some, such as alligators and some snakes, will even carry the eggs to water where they will be safe.
Birth
Like all vertebrates, reptiles reproduce sexually. In most species, fertilization of eggs occurs internally, but there are a few exceptions. Female lizards, for example, can retain sperm for several years, which then fertilizes subsequent clutches of eggs without additional contact with males. This is known as parthenogenesis, and it allows for the reproduction of offspring genetically identical to the mother.
The cloaca is the internal organ responsible for the production of amniotic fluid that encases and protects reptile eggs. It also functions as a sort of “sphincter” to prevent sperm from accidentally falling out during intercourse or while the animal is laying eggs.
Female reptiles typically lay a clutch of eggs, and a mother lizard will sometimes place her young in a nest she creates for protection from predators. Some snakes, such as boas and pythons, are ovoviparous, giving birth to live young.
During mating, male reptiles use their testicles to deposit sperm into the female’s cloaca, which is normally visible as a pair of bulges at the base of the tail. Most reptiles lack external genitalia, so it can be difficult for owners to determine the sex of their pet. If a male’s testicles prolapse, it is called a hemipene or hemiclopene and can be diagnosed by the bluish hue it gives off when the animal is anesthetized. Hemiclopenes have a good prognosis when treated, but analgesia and lubrication of the prolapsed tissue may be necessary before the herp can be repaired (Music and Strunk 2016).