The mother’s body does not provide a placenta, but does provide oxygen. Pups living inside the womb will live off a yolk sac from the egg until they are ready to hatch.
Oviviparity is when an egg hatches inside of the womb and the shark has a live birth. Depending on the species sharks will lay anywhere from 10 to 200 eggs. These eggs can spend weeks in the womb before being laid, and may taken months to hatch. They are typical encased a leathery pouch, referred to as a “mermaid’s purse.” The eggs are left unprotected and are often times eaten by predators before they can hatch. Sharks are “true oviparous” animals meaning the egg is fertilized in the womb then laid. Oviparity is when a shark lays eggs in a deposit in the water. Some species of shark that are viviparous include:Ībout 40% of all sharks are oviparous. The gestation period varies greatly, they tend to carry their pups anywhere from 7 months to three years. Viviparous sharks give birth to small litters, typically 2-20 depending on species. Sharks born through viviparity will have an umbilical cord located between the pectoral fins that delivers them nutrients and oxygen from the mother’s bloodstream. The shark pups will hatch inside of the womb and live off an placenta until they are ready to be born. Viviparous sharks have placental viviparity. Viviparity is when the egg is developed inside of the womb, eventually leading to a live birth, similar to how humans give birth. Once the eggs are fertilized, there are three ways the shark pups will develop: Viviparity This could also mean that during courtship, sharks are very particular in mate selection, looking for the best genetic match for reproduction. Sharks tend to have 2-100 pups in a littler depending on species. Scientists believe that all sharks are r/K-selected reproducers, meaning that they have small litters of high quality pups rather than large litters of low quality pups. This may either be a product of courtship displays or a means for the male shark to mount them. As for the mating ritual, scientists have only ever observed that many pregnant females have bite marks on their bodies and fins. Most sharks do have nursing grounds, places where the environment is conducive for healthy young where scientists can observe birthing.
It is also believed that many sharks species migrate to open waters for mating season, though it is unclear where or when this happens with most species so it is difficult to track. What is know is that most sharks take years, even decades, to reach the age of reproductive maturity. This is further complicated by the fact most sharks will not mate in captivity. Since shark mating is difficult to observe in the wild, very little is know about shark mating habits. Once an egg is fertilized, the reproduction process begins. It is believe that this happens with sharks swimming parallel to one another or possibly in smaller or bottom dwelling species, they may mount one another. Male sharks will insert their claspers into the oviduct and release semen fertilizing the female’s eggs. Females have oviducts, essentially a fallopian tube that leads to the womb. The males have a sex organ called a “clasper.” They are typically located on the pelvic fin, however chimaeras have claspers on their heads. Shark sexual organs are very different from other animals. Shark Academy: How Do Sharks Reproduce? The Reproductive Anatomy Of Sharks
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