Zoologists in Paris have said they are delighted and perplexed at the births of four rare Komodo dragons, whose paternity remains a mystery.
The four reptiles were born last month from eggs laid at the London Zoo by a female called Sungai.
Sungai normally lives at the Thoiry wildlife park west of Paris, but was lent to London as part of a European breeding program to help this badly endangered species.
But Sungai laid the fertilized eggs before even meeting her British lover -- and the last known possible time she could have become pregnant was two years ago, after contact with another Thoiry Komodo dragon called Kinaam.
The founder of Thoiry, Paul de la Panouse, said that there were two possible answers to the riddle.
"Either female Komodo dragons ... have the ability to store sperm or fertilized eggs for long periods, in this case for two years, or they are ... self-reproductive -- they produce clones of themselves," de la Panouse said.
Genetic tests will be carried out to try to explain the mystery.
The Komodo dragon is the world's biggest lizard, reaching up to three meters long. The creature is carnivorous, killing goats, deer and other mammals through deadly bacteria in its saliva.
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. (AFP)
1. Where does the mother Komodo dragon usually live?
2. Where were the eggs laid?
b. Near Paris.
3. Why was the mother Komodo dragon sent to London?
a. So she could lay her eggs.
b. So she could study English.
c. So she could get pregnant.
4. What is NOT an answer the scientists are considering?
a. Female Komodo dragons don't need males to reproduce.
b. The mother got pregnant when the zoo keepers weren't looking.
c. Female Komodo dragons can become pregnant long after they have had contact with a male Komodo dragon.