Sharks how do they give birth

In some cases, such as baby sand tiger sharks Carcharias taurus , this predatory behaviour starts early. Intrauterine cannibalisation, to use the correct term, means the mm long sand tiger shark embryos in the womb will feed on their fellow brothers and sisters until only the two biggest and strongest are left.

They then emerge as stronger and healthier hatchlings who, as a result of their size, are less likely to be preyed upon. Shark parenting certainly focuses on tough love. Lemon sharks Negaprion brevirostris , named for their pale-yellow skin that camouflages them in sandy waters, have their young in mangrove forests or lagoons. The pregnant females will wait for high tide before swimming into the forest to give birth, not a phrase you hear every day.

As soon as the baby sharks are born, however, the mothers return to the deep ocean, leaving the pups to fend for themselves in the shallower water. The juvenile lemon sharks stay in the lagoon for about two years, honing their hunting skills, before swimming out to sea on the high tide.

This phenomenon, called parthenogenesis, means giving birth at the onset of maturity without mating. Parthenogenesis is more commonly found in plants, some lizards and chickens. Researchers believe that zebra sharks may be able to adapt their reproductive strategy to environmental circumstances , such as the lack of a mate, which is especially interesting given that zebra sharks are endangered.

Researchers are now monitoring whether the offspring born of parthenogenesis will be able to bear offspring from mating. Your information will be used in accordance with our privacy policy. You can unsubscribe at any time. Hammerhead sharks are viviparous, giving birth to live young. Although the young initially rely on a yolk sac, this eventually becomes a placenta-like structure.

In some species, the female will produce unfertilised eggs, which are eaten by embryos. This is known as oophagy 'egg eating' and occurs in species including the shortfin mako Isurus oxyrinchus and bigeye thresher sharks Alopias superciliosus.

Embryos of other sharks survive by feeding on their smaller siblings. This is called intrauterine cannibalism or sometimes as embryophagy 'embryo eating'. This is known to occur in sand tiger sharks Carcharias taurus. Oophagy occurs in shortfin mako sharks, a species in the same order as great white and goblin sharks. Placental viviparity occurs in some species of shark - once the yolk sac has been depleted, it attaches to the uterine wall, acting as a pseudoplacenta.

The young get their nutrition through this link. Hammerhead family Sphyrnidae , blue Prionace glauca and lemon sharks Negaprion brevirostris all produce offspring in this mammal-like way. Find out more about life underwater and read about the pioneering work of the Museum's marine scientists. Explore facts about this huge shark - which can open its mouth up to a metre wide - including where you might see one in the UK. Just how big was megalodon and could this giant predator still be lurking in the dark depths of the ocean?

Appearing to flash a toothy grin, this hammerhead seems eager to show that sharks aren't as fearsome as they're often made out to be. Get email updates about our news, science, exhibitions, events, products, services and fundraising activities. You must be over the age of Privacy notice. Smart cookie preferences. Change cookie preferences Accept all cookies. Skip to content. Read later. You don't have any saved articles. By Emily Osterloff. What is a mermaid's purse? Spiral shark eggs Bullhead sharks produce spiral- or corkscrew-shaped eggs.

The physical cost to the mother shark's health is minimal. All nutrition for the developing shark embryo is encased within the satchel's hard casing. Viviparous birth is much like a human's gestation period. The embryonic shark is brought to full term and is born live. The female shark has a placental sac that nourishes and strengthens the baby shark for the rigors of survival at sea. In the cases where the female shark does not have a placental sac, her body produces a milky substance that nourishes the embryonic shark before birth.

Viviparous shark birth exacts a cost on the mother shark's health due to the investment her body undertakes to bring the embryos to term.

Ovoviviparous birth is an interesting shark birthing process that takes very little toll on the mother but is fatal to many young sharks. During Ovoviviparous shark birth, the mother never produces a placental sac but rather carries the young sharks alive in utero.