What is a virgin birth? A step-by-step image shows how a female stingray was able to become pregnant despite living alone

A virgin birth may sound miraculous, but in some animals this miracle is completely natural.

Certain animals such as sharks and snakes are able to produce healthy offspring without ever mating, through a process known as parthenogenesis.

Recently, Charlotte the stingray became pregnant in the US without even seeing a member of her own species.

But was this divine intervention, or just another wonder of the natural world?

This step-by-step image reveals the fascinating details of how Charlotte became pregnant without mating.

Charlotte, a round stingray who spent much of her life at the Aquarium and Shark Lab in Hendersonville, North Carolina, is expected to have four pups within two weeks.

But her keepers say there is no chance she became pregnant by mating with another member of her species.

Most animals create their young through sexual reproduction, in which a male and a female exchange genetic material.

The mother’s egg contains half a set of genes, supplemented with the genes in the male’s sperm.

However, certain animals such as sharks, birds, snakes and even crocodiles can reproduce in different ways.

Scientists believe that Charlotte became pregnant through a process called ‘facultative parthenogenesis’.

During facultative parthenogenesis, the offspring receives its complete set of genes from its mother.

Instead of fertilizing the egg with a sperm cell, it is fertilized by a cell taken from the mother herself.

This “polar cell,” as it is called, connects to the egg and initiates cell division, leading to the creation of a fully developed embryo.

Because the polar cell also contains half a set of genes from the mother, the offspring is almost a perfect clone of its parent (taking into account mutations and copying errors).

Kady Lyons, a researcher at the Georgia Aquarium in Atlanta, where Charlotte the stingray is kept, says Charlotte’s pregnancy is the only example she knows of of round stingrays.

Ms Lyons said: “I’m not surprised because nature finds a way to make this happen,” she said.

‘We don’t know why it’s happening.

“Just that it’s a really fun phenomenon that they seem to be capable of.”

And although Charlotte shares her 2,200 liters with five small sharks, her keepers insist it would have been impossible for her to breed them.

“We need to make it clear that there are no shark ray scandals happening here,” Ms Lyons added.

Scientists are still not entirely sure what exactly causes virgin births or why some animals are capable of them and others are not.

But if we find out, it could help answer the question of whether it is possible for humans to reproduce asexually.

For a mammal to have a virgin birth, it would likely have to undergo a slightly different type of parthenogenesis.

Instead of the mother fertilizing the egg with a cell from her body, called apomixis, the egg would have to double its genetic content, divide and then recombine.

In this process, which scientists call automixis, the egg would end up with the normal number of chromosomes without the need for any additional genetic material.

But even then, the chance would be ‘one in a billion’ that the egg will develop into an embryo.

Professor Russell Bonuriansky, an ecologist at the University of South Wales in Australia, told MailOnline that mammals may have evolved to make this type of reproduction impossible.

Professor Bonuriansky says: ‘Some animals can do this, but for some reason most cannot.’

“(It) prevents eggs from developing into embryos in the ovaries, which would be fatal to female mammals,” he continued.

However, scientists are investigating how to achieve asexual reproduction in mammals.

Scientists in China even announced that they were able to achieve parthenogenesis in mice without any male genetic DNA.