Great Elephant Birds became extinct in the mid-1600s
A giant egg laid in the 17th century and thought to be one of the biggest in the world has gone on sale for £5,000.
The egg, with circumference of more than 3ft, was laid by a Great Elephant Bird of Madagascar and is on sale at the Chelsea Antiques Fair in London.
It belongs to antique dealer John Shepherd, of Ashford, Kent, who said he was delighted to be selling it.
He bought the egg last year after seeing David Attenborough discover one while filming in Madagascar.
Mr Shepherd, a trained palaeontologist, said: "The egg has a great social history. The Madagascan Elephant Bird was the only giant bird to exist with man and man caused its extinction.
"It's nice to be able to show children today about environmental issues that have been going on for hundreds of years."
The egg would have contained the chick of a baby Great Elephant Bird but is now hollow after it was broken and pieced back together.
The herbivores, which were hunted by the natives of Madagascar, became extinct in the mid-1600s.
They weighed about half a ton, but predators including pigs ate their chicks and destroyed their eggs.
The flightless bird, the largest to have ever lived, resembled a heavily-built ostrich. It had long legs, talons, and stood at more than 10ft tall.