With around 500 different species of sharks swimming around in our oceans, it should come as no surprise that their reproduction process varies from species to species.
Sharks can be found in almost all ocean habitats, from warm, tropical reefs to the coldest and harshest oceans of Antarctica.
Today, we’re going to take a closer look at the sharks’ reproduction process and answer a question that often comes up when discussing these fascinating marine animals. Do sharks lay eggs?
The majority of shark species give birth to live young. They have eggs inside of their bodies that they incubate until they hatch. However, some are oviparous, meaning that they lay eggs just like fish.
Do Sharks Actually Lay Eggs?
Some species of shark do lay eggs, however, most species have eggs that they incubate inside of their bodies before they hatch, and then the mother gives birth to live young.
Unlike fish, which produce a large number of eggs that few reach maturity, sharks produce fewer but larger offspring that have a much better chance of reaching adulthood.
Whichever way a shark pup is born, it is born for survival. Once born, the shark pup is independent and will swim away from its mother and begin to fend for itself.
What Type Of Shark Lays Eggs?
There are much fewer shark species that lay eggs than give live birth, and it’s often the smaller species that lay eggs.
Below are some of the shark species that lay eggs:
- Horn shark
- Cat shark
- Swell shark
- Bamboo shark
- Carpet shark
- Wobbegong sharks
These sharks give birth to eggs on the bottom of the ocean. The baby shark develops in there living off a yolk sac filled with nutrients.
After a few months, once the baby has started to grow, the miniature version of its parent will be born, often a few months to a year after its gestation.
What Kind Of Sharks Give Live Birth?
Viviparous sharks are live-bearing sharks that give birth to live young that have developed inside of the mother shark.
These shark babies receive nutrients and oxygen from their mom through an umbilical cord, just like how humans are born.
Below are some of the shark species that give birth to live young:
- Hammerhead sharks
- Blue sharks
- Bull shark
- Mako sharks
- Lemon sharks
There are much more shark species that are viviparous and give birth to live young. These young sharks are given a better chance of survival as they are not at the mercy of ocean predators in egg form.
Do Sharks Give Birth Any Other Ways?
Some species of shark are known as ovoviviparous, also known as Alpacental Yolk Sac Viviparous.
In this system, the mother produces eggs just like the oviparous system, but instead of laying her eggs on the bottom, she carries them inside her body until they hatch.
Once the babies are ready to be born, you may think that the shark was viviparous, but the babies had no umbilical cord inside, they lived off a yolk sac.
The Sand Tiger shark is an ovoviviparous shark, but this species has a strange variation known as intrauterine cannibalism.
The mother will produce up to 50 pups in each of the two uteruses, but the first baby in each uterus that reaches only around 4 inches long begins to eat its siblings.
After around 12 months of gestation, the mother sand tiger shark gives birth to only two sand tiger sharks, each around 3 feet in length.
These pups are very well fed, as they’ve spent so long inside of their mother feeding on their siblings, when they are born they are already in a great position for survival.
How Many Eggs Do Sharks Lay At A Time?
Many of the species of shark that lay eggs only lay around 20 each year, with hatching success rates of around 57%.
Shark eggs face many threats in the ocean, from being eaten by predators to being washed away and never found again.
The whale shark is the species of shark that lays the most pups of any shark, at around 300 pups per time, but then again they are the size of a full-sized bus.
Whereas the thresher and sand tiger sharks only produce two pups at a time the blue shark produces around 135 at a time.
Gestation is typically long too, averaging around 9-12 months, but some species such as the baby spiny dogfish take around 22 months for their young to develop.
More On Shark Eggs
Oviparous sharks that lay eggs will try to find a safe and secure place so that the mother can lay her eggs down and give her pups the best chance of survival.
The egg has a casing around it once it is laid which protects the embryo and yolk from predators as it is thick and leathery.
Oftentimes the embryo can be seen wriggling around inside and starting to grow. The actual casing itself is given the name “mermaids purse” or sometimes “devils purse”.
The casing is made from keratin, the same fibrous protein that is also found in human fingernails and hair.
When the pup is grown and ready to enter the world, it chews a hole in its egg casing to get out, and then life as a shark begins.
So, do sharks lay eggs? Yes, they certainly do, but not all of them. Many species of sharks are viviparous or ovoviviparous which means they carry their young inside of them before giving live birth.
However, some species of sharks lay eggs on the bottom in what’s often called a mermaid’s purse.
It’s an egg capsule that protects the embryo and allows the shark to grow before it reaches the point where it’s ready to break out and bites its way through the egg sac.
Hopefully, you’ve learned something new today about the shark’s reproduction process and now know some sharks that lay eggs and some that do not.
Thanks for taking the time to read this article and if you have enjoyed it, feel free to stick around to learn more about sharks and the many other types of marine life we discuss here.
Hi, I’m George – the founder of MarinePatch. I created this blog as marine wildlife has been my passion for many years. I’ve spent over a decade in the marine wildlife industry and spent years out in the field conducting research. In today’s modern world, an online blog is the best place for me to share my findings and reach as many people as possible to help educate and inspire others. Enjoy your time here and you’re welcome back anytime!