Tuesday, November 17, 1998 Published at 18:05 GMT
Nesting in the mud
Countless fossilised dinosaur eggs discovered in Argentina
Scientists have unearthed an extraordinary dinosaur nesting ground strewn with hundreds of thousands of fossilised eggs. BBC News Online's Science Editor Dr David Whitehouse steps back in time.
Imagine this. Hundreds if not thousands of dinosaurs gathered together in giant herds squelching around on mudflats near ancient streams.
Driven by instinct, female plant-eating dinosaurs are converging on a nesting site that may have been used for countless dinosaur generations.
Perhaps they are returning to the place where they were born?
It is a place of noise and bustle as the females pick their spot, perhaps fighting over a particularly appealing patch of flat mud in which the eggs will be laid.
Strange threatening cries fill the air. They come from winged dinosaurs, the ancestors of today's birds. Occasionally one of those flying reptiles will see an abandoned egg and swoop down to get it.
Each female has her territory where she lays her eggs. Perhaps she is helped by the male in guarding them, perhaps she guards them alone or perhaps she abandons them.
Fights are always breaking out at the edge of the nesting site as carnivorous dinosaurs see the chance of a meal.
They are mostly interested in the eggs, but a weak adult would also do nicely.
At the edge of the site adult males patrol in numbers to deter any attackers. Being plant eaters they are not particularly aggressive. They rely on numbers to intimidate aggressors.
After the eggs are laid, they are quickly covered in mud. This protects some of them from scavengers, but there are still many dinosaurs who kick up the mud to look for them.
Some of the eggs fail to develop and stay in the mud becoming fossilised as the mud dries and the land changes over geological time.
Such a dinosaur nesting place exists today. It is in the Patagonian badlands of South America.
Scientists call it 'Auca Mahuevo' - huevos is Spanish for eggs.
They say the fossilised eggs are so plentiful at Auca Mahuevo that it is virtually impossible to walk without crushing shell fragments under foot.