Virgin birth Komodo

British zoologists have a Christmas tale of their own to tell: a rare giant lizard, the komodo dragon, is about to give "virgin birth".

In a study published in the science journal Nature on Thursday (local time), they say they have unravelled a mystery surrounding a komodo dragon named Flora, one of two dragons at Chester Zoo, in northern England.

Flora laid 11 eggs in May this year, three of which collapsed.

These three eggs were opened and were found to contain embryos, showing they had been fertilised.

But who was the daddy? Flora had never mated with a male dragon or even mixed with one.

DNA tests have now proven that Flora was both the "mother" and "father" of the fertile eggs.

"Although other lizard species are known to be able to self-fertilise, this is the first time this has ever been reported in komodo dragons," said Kevin Buley, a co-author of the paper, who is the zoo's curator of lower vertebrates and invertebrates.

"Essentially, what we have here is an immaculate conception, and because the eggs were laid back in May, it is not beyond the realms of possibility that the incubating eggs could hatch around Christmas time.

"We will be on the lookout for shepherds, wise men and an unusually bright star in the sky over Chester Zoo," he added in a wry reference to the biblical account of Christ's birth.

Self-fertilisation in this way is called parthenogenesis.

Under it, the species makes a copy of its own genetic code.

Zoologists at Thoiry Zoo, west of Paris, announced in April they suspected parthenogenesis was behind the birth of four baby dragons to a female called Sungai.

Sungai normally lives at Thoiry, but was sent to London to mate with a male dragon there under a European breeding program.

The komodo dragon (Varanus komodoensis) is the world's biggest lizard, with adult males reaching up to three metres long and weighing up to 90 kilograms.

The dragon is found on the Indonesian islands of Komodo, Rinca, Gili Motang and Flores, but its numbers have dwindled to around 6,000 as a result of poaching and invasive species