There are approximately 400 different species of sharks, of these 400 species about 40% of them lay eggs. All sharks mate through internal fertilization, during which the male shark inserts one or both of his claspers into the female’s reproductive tract and deposits his sperm. The mother may then either lay the fertilized eggs, or they might develop partially or fully inside of her. The young sharks get their nourishment from a yolk sac or through other methods.
Egg Laying Sharks
When a shark’s eggs are laid, they are in a protective egg case. These egg cases have tendrils, which allow them to attach to substrate such as corals, seaweed, etc. Sometimes these cases will wash ashore on the beach. In some species of sharks the egg cases are pushed to the bottom of the ocean or into crevices between and/or underneath rocks.
In oviparous shark species (egg laying), the young sharks get their nourishment from a yolk sac. These young sharks may take several months to hatch. In certain species of sharks, the eggs stay inside the female shark for a period of time before they are laid, this allows the sharks to develop fully and spend less time in the immobile egg cases before they hatch.
Types Of Sharks That Lay Eggs
Just a few species of sharks that lay eggs include:
- Bamboo sharks or carpet sharks
- Swell sharks
- Cat sharks
- Horn (bullhead) sharks
Live Bearing Sharks
The other 60% of shark species give birth to live young, rather than lay eggs. This is known as viviparity. In these species of sharks, the young remain in the mother’s uterus until they are born.