Lifestyle of the dodo revealed

Scientists examining the structure of the birds' bones have found new information about how quickly dodos grew, when they laid eggs and when they moulted.

Researchers from the Museum and the University of Cape Town (UCT) combined evidence from the bones with the historical accounts of sailors that visited Mauritius, the birds' home.

They also used information about the lifestyle of birds that still live on Mauritius.

This is a breakthrough for Dr Lorna Steel, senior curator at the Museum, who began the work around a decade ago. The researchers were initially reluctant to cut up the exceptionally rare dodo bones from the Museum's historic collections.

Dr Steel says, 'Luckily, recent excavations in Mauritius provided us with a few broken bones that could be sacrificed.

'But it wasn't quite enough evidence to make any strong conclusions about dodo lifestyles.

'So I was very pleased when the UCT team contacted me to say they had been given some more dodo bones to analyse and they wanted to team up.'

When did the dodo bird go extinct?

The dodo died out within a century after Dutch explorers arrived on Mauritius in the late 1500s, so little evidence has been left behind of what it really looked like or how it lived.

Some sailors' accounts have survived, but they are often limited or unreliable - seamen tended to spin their dodo-sighting tales for dramatic effect rather than scientific accuracy.

A stormy summer season

According to evidence in the different layers and types of tissue of the 22 bones examined, the dodo seems to have adapted its lifestyle to Mauritius's stormy summer, from November to March.

During this period, heavy rain and strong winds can strip trees of leaves, flowers and fruit, causing severe food shortages for the island's animals.

The dodo bones show repeated lines of arrested growth, which the researchers suggest correspond to the harsh conditions of the summer months when the birds were starved of food.

The scientists then used these lines to estimate the time that other events happened to the bird.

Egg laying and fast growth

In common with many modern birds living on the island, the breeding season for dodos appears to have begun around August.

Once chicks hatched, they grew quickly to almost adult body size, attaining sexual maturity before the stormy summer began.

Moulting began after the summer had passed, around March, with the replacement of the feathers of the wings and the tail.

By July, the moult would have been completed and the bird would have had a chance to fatten up, ready for the next breeding season to begin.

A promising approach

With little other evidence left of the dodo, the study of its bones seems to be the most promising avenue to understand more about how it lived, said Dr Julian Hume, a Museum avian palaeontologist who worked on the study.

He says, 'All that remains of the dodo today is a handful of images, a few accounts, a unique head with soft tissue in Oxford, and lots of fossil bones. Of these artefacts, it is only the study of the bone structure that is providing us with precious more information about the dodo's life history.'

Dr Steel also has plans to use the same approach on other animals. She says, 'We are already looking at the microscopic bone structure of some other extinct birds.'