Great white shark reproduction remains largely mysterious to science but we do know the act of mating is so rough that the female ends up with scars
When it comes to great white sharks, one mystery stands out above all others: how do these iconic apex predators get it on?
How do great white sharks mate?
Great white sharks (Carcharodon carcharias) – also known as white sharks or white pointers – are slow to reach sexual maturity. Males aren’t ready to reproduce until they’re in their 20s and females in their 30s.
There are still many questions around white shark reproduction. Mating has never been scientifically documented in detail and is rarely observed. Much of what researchers understand about how white sharks have sex has been pieced together from clues – like the scars left behind after the act.
As you might imagine from a creature with a mouth full of razor blades, the mating ritual of white pointers seems quite ferocious. The male grips onto the female with its teeth so she can’t get away. Females’ skin can be three times thicker than a male’s but she can still be left with obvious “love bites” on her fins and back, according to the Shark Trust.
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When a seal observer from the New Zealand Department of Conservation came across two white sharks mating in 1991, it was so ferocious he thought the animals were embroiled in an epic fight.
“One animal appeared to be attempting to grasp the other with its great mouth, making great gouges in its side,” he says. “They had eventually become motionless, one under the other, turning over from time to time, belly to belly,” the observer continues. The “obvious copulation” lasted for 40 minutes, according to his report which has not been verified. Then, the sharks swam away in different directions.
A second report of white sharks mating comes from Dick Ledgerwood who saw the rare event while on a fishing trip in 1997. He tells the Guardian how he saw the two sharks “locked together” in shallow waters, just four metres deep. “It was two sharks wedged close together, and they were just revolving round and round, very, very slowly,” he says.
While they are locked together, the male fertilises the female by inserting one of his claspers – modified pelvic fins that are used for reproduction – into her cloaca (an opening that leads to her womb).
White sharks reproduce ovoviviparously (say that three times fast!), which means the female’s fertilised eggs hatch inside her body. As the embryo develops (still inside the mother’s uterus), it is nourished by the egg’s yolk sac before the pup is ready to be born. Scientists think the gestation period is around one year, although no-one has recorded a white shark giving birth – yet.
There are usually between two and 10 pups in one litter, although as many as 17 have been recorded. Around 63% survive their first year.
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When the babies are born, already measuring around one and a half metres, they’re ready to take on the world. The pups can swim as soon as they’re born and are fully independent straight away. Their mum won’t look after them (and might even try to eat them) so they just have themselves to rely on.
While inside the womb, embryos need to grow big and strong ready for the dangers of life in the ocean. To do this, they feed on unfertilised eggs in the uterus. This is called oophagy.
Because white sharks are slow to mature and only have a few pups in each litter, they are vulnerable to human threats. When populations decrease – due to things like overfishing or pollution – they are slow to bounce back.
So, scientists aren’t just being pervy when they say they want to see more white sharks having sex. The more we can learn about great white reproduction, the more knowledge we will have to help the species thrive.
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