How much is the big, partially fossilized egg of an extinct giant bird worth? Well, someone paid more than $100,000 for this egg at an auction in London. (Matt Dunham/Associated Press)

A massive, partly fossilized egg laid by an extinct elephant bird has sold for more than $100,000 at a London auction.

Christie’s auction house said the winning bidder paid $101,813 for the foot-long egg, nearly nine inches in diameter.

Before the sale, it had been estimated that someone would pay $30,000 to $46,000 for the egg. It was sold to an anonymous buyer over the telephone after about 10 minutes of bidding.

Elephant birds were wiped out several hundred years ago. Human activity, including hunting the eggs for food, is thought to have helped the birds disappear.

The egg was laid on Madagascar, an island off the coast of Africa. It is believed to date to before the 17th century.

Flightless, fruit-gobbling elephant birds resembled giant ostriches and could grow to
11 feet tall. Their name comes from a mythological bird that was thought to be big enough to grab an elephant in its claws.

Christie’s said their eggs are 100 times the size of an average chicken’s egg.