Great white sharks are one of the World’s most mysterious animals. Even though many studies have been conducted on these beautiful ocean animals, where they mate and give birth still remains a mystery. What scientists believe they do know is how these sharks mate and the type of reproduction that is involved. So I am going to tell you a little info about the birds and the bees…
First up, the most common question I get asked on White Shark Projects cage diving boat Shark Team is “How do you tell if it is a female or male?” Well, there are some external differences between males and females.
Male sharks have modified pelvic fins called claspers, which are used during reproduction. These basically look like “two sausages” as our crew would say… whereas the females lack these claspers.
There are four types of reproduction that have been observed in sharks;
In oviparous sharks, a tough leathery case is formed around the egg, which protects it while it is developing. The female shark deposits these egg cases in the sea. The shape of the egg cases vary greatly between species but many of them look like purses – so are commonly called “mermaid’s purses. Most hatch within about two months but sometimes can take up to nine months – depending on temperature. Examples of oviparous sharks include species that we find around here in Gansbaai, such as the puffadder shyshark and pyjama catshark
These sharks produce a thin tissue covering around an egg or group of eggs (called a candle) and this stays inside the female’s body. At maturity the tissue is shed and the young sharks continue to develop inside the mother for some time before being born live. We also find shark species that are ovoviviparous around South Africa, such as our infamous great white shark in Gansbaai, as well as mako and thresher sharks.
Viviparous sharks develop inside the female’s oviducts for several months and are nourished through an umbilical cord, in the same way that mammals do. The young sharks are born live. In some species, unborn pups will eat others and only the strongest one is born. The bronze whaler sharks we may also encounter during our cage diving trips are viviparous.
Incredibly, a few female shark species are capable of reproducing without a male present. This ability is known as parthenogenesis or “virgin births”. This has been discovered from some species that have been kept in captivity, such as, zebra sharks and hammerheads.
Great white shark reproduction:
Although never witnessed by any human, from scars on the females fins and body, scientists believe that great white sharks have a typical courtship ritual like most shark species. This involves the male biting the female to hold her in place during insemination.
Dissections of deceased pregnant sharks suggest that the great white shark is ovoviviparous. It is speculated that the gestation period (pregnancy) of great white sharks is between 12 – 18 months and the common amount of litter are between two and ten pups. It also appears great white shark embryos feast on unfertilized eggs while developing inside the mother, a practice known as oophagy. It does not appear that they eat the fertilized eggs, as a few other species of shark has been known to do. It is also thought that the size of the pups when born are between 1 – 1.5 metres in length.
Great white sharks are elusive creatures and as of yet we do not know exactly where their mating of birthing areas are. Life history traits such as late sexual maturity (possibly 35 years old in females), low reproductive rates and long gestation period, along with both human and environmental pressures mean that this species is vulnerable to population decline.
Here at White Shark Projects we believe that education is key to conservation and we do our best to teach people all we can about this incredible species. As Baba Dioum said in 1968;
“In the end, we will conserve only what we love; we will love only what we understand and we will understand only what we are taught.”