An enormous fossilized egg belonging to an extinct elephant bird has sold $101,813 at an .

The egg of the now-extinct bird is a foot long long and nearly nine-inches in diameter. The initial value of the egg, which was sold in London, was just half of what it sold for, at about $50,000 (20,000 -30,000 pounds).

An anonymous telephone buyer purchased the egg at Christie's auction house in London. Competitive bidding had continued for 10 minutes before the purchase was confirmed.

Elephant birds existed back before the 17th century in the island of Madagascar. The birds, which have been extinct for several hundred years, belonged to a family of birds called Aepyornis.

Aepyornis are the heaviest of birds and they are believed to have grown up to 3 meters tall and known to have weight up to 400kg. Some eggs of the Aepyornis have measured 1 meter in circumference.

It is not known why the elephant birds became extinct.

The birds looked like giant ostriches, with their eggs 100x bigger than an average chicken egg.