But this giant egg is a great survivor. It was laid around 400 years ago by one of the great elephant birds of Madagascar.
Before becoming extinct in the 17th century, the flightless creature was the world's largest bird, standing 10ft tall and weighing half a ton.
Duncan Phillips holds a Giant Elephant Bird of Madagascar egg, which went on sale in London today.
The egg, which is more than 3ft in circumference, was discovered by Victorian explorers and has since been held in private collections.
Its current owner is antiques dealer John Shepherd, of Ashford in Kent, who bought the egg after seeing David Attenborough discover one while filming in Madagascar.
Mr Shepherd, a trained palaeontologist, has decided to sell the egg, which is on display at the Chelsea Antiques Fair, which runs until Sunday.
The egg is larger than a rugby ball and measures more than 3ft in diameter.
It is expected to fetch at least £5,000. He said: 'The egg is a talking point. It's very eye-catching and it has a wonderful simplicity about it. It stands on its own.
'It 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.'
Great elephant birds became extinct after being hunted by the natives of Madagascar.
Even though the bird weighed about half a ton, it also suffered at the hands of other predators such as pigs who 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.
The bird as it would have looked 400 years ago, and right its skeleton reveals how much larger it was compared to its giant eggs