Dr Christine Dudgeon

So we actually in Australia call them leopard sharks and that's because their adult forms are spotty and the babies are stripey and they're the largest of the egg-laying sharks.

Full size is a bit over two metres and maybe about 40 kilos.

Leonie was housed with a male named Leo and they had many babies together.

And this was actually becoming a problem because when they grow up and they're over two metres in length, that's quite hard to house all of them.

Sharks that are egg layers will lay eggs much like a chicken.

So they will lay what we call wind eggs, which have nothing in them, or yoked eggs where there's no embryo.

So like a chook without a rooster, Leone was still laying, laying, laying.

But a couple of years later, some of her eggs had embryos in them.

None of these embryos developed to the point of hatching.

Oh.

The next year, however, she started laying eggs again.

Ooh.

And some of these eggs had embryos in them and some of the eggs actually hatched.

How did she have shark pups?

There were essentially two potential explanations for it.

So in the literature, they often talk about sperm storage in sharks.

And this has been proposed to be up to around four years in one species.

It could be sperm storage, but it also could be parthenogenesis and we can test for that.

Yes, we found they were parthenodes, so we tested the last litter of pups that Leonie and Leo had together and could show that they were sexually produced.

And then all of the pups after Leo had been removed, the embryos and the pups that developed, they were all parthenodes.