Thursday 07 June, 2001
Jurassic Eggs
In November 1997 a dinosaur nesting site was uncovered in Auca Mahuero, Patagonia, Argentina. Researchers discovered hundreds of sauropod eggs. This month the eggs go on display to the general public at the Los Angeles Natural History Museum.
Science in Action examines the eggs and finds out how this discovery has enhanced our understanding of dinosaurs.
The discovery of the nesting site in Patagonia was a major coup for dinosaur experts. Prior to this, the only evidence of the existence of sauropods were footprints or bones. The nesting site has given new insight into the reproductive behaviours of sauropod dinosaurs.
What we know about Sauropods
Sauropod is the classification term for a particular type of dinosaur. The diplodocus is a well-known example. Sauropods were some of the largest dinosaurs ever to have existed. Enormous herbivores, they could grow to the size of a double decker bus or bigger.
These dinosaurs had very long necks and tails and small heads. They are likely to have fed on trees. Evidence of their dentures show that they had teeth suited to plucking and chewing plants.
They were geographically widespread. Remains have been found on every continent except Antarctica.
Our knowledge of these great beasts is still very limited but with discoveries like the nesting site we are learning more about their behaviour and life style all the time.
The Eggs
Luckily, when the eggs were laid about 18 million years ago, they were rapidly buried or surely a scavenger would have destroyed them. They remained preserved in the earth until Dr Luis Chiappes and his team excavated them in 1997.
Although the eggs had become mineralised over time, it is still possible to examine the embryos inside them. Partly crushed from millions of years under the earth, the skull of a baby dinosaur is still visible in the egg that Dr Chiappes showed Science in Action.
Dinosaurs Like Us
Amazingly while bones and footprints found in the past indicate that sauropods were vast in size, the embryos and eggs suggest that when first hatched, sauropods were of a relatively small size. In fact they were probably no bigger than a new born baby.
Egg Care
Clusters of eggs were laid in 1.5m long groupings suggesting that females may have gathered together to lay their nests. It is thought that they nested over the span of a season.
However, the limited number of shells between clutches suggests that the sauropods moved on after laying their eggs. But how did the young survive if the sauropods did not stay behind to guard the eggs from the ravages of predators?
Some dinosaur experts believe that a few adults remained behind to protect the eggs. Others argue that the eggs were laid in such vast quantities that even if the predators ate 80% of them, the remaining 20% were enough to continue the population.
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| TINIEST GIANTS: Discovering Dinosaur Eggs |
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The exhibition of these amazing eggs and the incredible expedition to excavate them is on at the Los Angeles Natural History Museum.
May 19th to October 14th. |
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