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From the shedding of skin to smelling with their tongues, snakes fascinate humans for many reasons.

But one reticulated python has given us a new reason to be amazed, because she has produced six babies - without mating.

Thelma the snake's virgin birth, through a process known as parthenogenesis, is the first to be documented in the world's longest snake species.

A reticulated python called Thelma has produced six offspring, without the help of a male. The virgin birth, or parthenogenesis, is the first to be documented in the world's longest snake

Parthenogenesis is fatherless reproduction in animals that usually requires two parents to produce offspring.

The 11-year-old reticulated python produced her young in June 2012 at the Louisville Zoo in Kentucky and new research has revealed how the feat was achieved.

Thelma lives with another female python called Louise and has not had any male company for years.

The 20ft, (six metre) snake, which weighs 200lbs (91kg) laid a clutch of 61 eggs in the summer of 2012. 

The 11-year-old reticulated python produced her young in June 2012 at the Louisville Zoo in Kentucky. Her offspring are half clones. Three of them have retained her exact colouring, while the others (one of which is pictured) have bright yellow and black patternation known as 'super tiger' markings

The eggs were covered and brooded by the coiled female for two weeks before being removed by zookeepers for examination.

'It is not uncommon for a snake to lay infertile eggs, so the staff was surprised when the eggs appeared to be full and healthy instead of shrunken and discolored shells - typical of infertile reptile eggs,' said Bill McMahan, Curator of Ectotherms at the zoo.

A decision was made to artificially incubate some of the eggs to ascertain whether they were fertile.

On September 12, 2012, the first of six healthy reticulate pythons hatched with an average individual weight of 5.23 ounces (148.3 grams).

Dr McMahan said: It is a very exciting thing to be able to witness something like that first hand, especially something that has never been documented before in this species.'

To confirm whether Thelma's offspring were born via parthenogenesis, shed skins from her and her offspring were sent to the University of Tulsa's molecular ecology laboratory in Oklahoma.

Genetic testing revealed that the snakelets were produced by the mother (pictured) alone, without sperm from a male snake. Parthenogenesis is caused when cells known as polar bodies – which are produced with an animal's egg and usually die, behave like sperm and fuse with the egg, triggering cell division

'We didn't know what we were seeing. We had attributed it to stored sperm. I guess sometimes truth is stranger than fiction,' he told National Geographic.

Genetic testing revealed that the offspring were produced by the mother alone, without sperm from a male snake.

It's caused when cells known as polar bodies – which are produced with an animal's egg and usually die, behave like sperm and fuse with the egg, triggering cell division. 

This process is known as terminal fusion automixis, according to the study published in the Biological Journal of the Linnean Society.

Interestingly, despite not having a father, the snakelets are half clones of the mother, with three retaining her pattern, with the others displaying striped of brighter yellow.

Virgin births have been seen in other reptiles before, including other snake species, according to James Hanken, a professor of herpetology at Harvard University in Massachusetts.

It is being documented in more and more species, including birds and sharks, mainly due to research by Warren Booth at the University of Tulsa.

He thinks that the discovery in pythons will help scientists learn more about snakes' evolutionary family tree and thinks that while no-one knows what causes parthenogenesis, it may have something to do with females being kept in captivity far away from males.