Dodos didn't die until later than thought
Date: 20-Nov-03
Country: UK
Author: Patricia Reaney
The last confirmed sighting of the lumbering, dim-witted bird that weighed about 23 kilos (51 lb) was on the island of Mauritius in the Indian Ocean in 1662, less than 80 years after it was first sighted.
But new calculations by scientists in Britain and the United States suggest they existed for another three decades.
"Our estimate is about 30 years," Andrew Solow, an ecological and environmental statistician at the Woods Hole Oceanographic Institution in Massachusetts, said in an interview yesterday.
The dodo was already rare by the time of the last confirmed sighting and had not been seen for about 25 years. So it probably managed to survive longer than expected, he said.
"We used a statistical method to try to estimate how long past that last sighting the dodo was actually extinct," added Solow, who reported the findings in the science journal Nature.
Solow and David Roberts, conservation biologist at Britain's Royal Botanic Gardens near London, used data on the last 10 recorded sightings to date the demise of the birds, driven to extinction by the destruction of their forest habitat and the arrival of hungry sailors and animal predators to the island.
Knowing the time of extinction of a species is important for understanding why an animal became extinct and for the conservation of modern species.
"There are reasons for wanting this kind of information," Solow said.
Stuart Pimm of Duke University in Durham, North Carolina, said the calculation used to pinpoint the demise of the dodo could be used to date other extinctions.
"Application of Roberts and Solow's method might suggest which dinosaurs (if any) had predicted dates of extinction well before the rest of their kind," he said in a commentary in the journal.
The scientists chose the dodo because its disappearance is the cause of its fame. "Probably no one would have heard of it if it had not been extinct," Solow said.
