For the first time, scientists have unravelled the complete life cycle of the dodo.
Dodos lived in Mauritius but went extinct within a century after European sailors colonised the island in the sixteenth century.
Now, a study of its ancient fossils has revealed the extinct flightless pigeon moulted just like modern birds – completely changing its colour with fresh plumage, new research suggests.
Dodos also experienced rapid growth rates from a young age, the research found, in order to plump them up early to survive the harsh cyclone seasons of the southern hemisphere.
The dodo moulted just like modern birds – completely changing its colour with fresh plumage, new research suggests. The study explains the extinct bird’s moulting stages in paintings based on the accounts of mariners hundreds of years ago
Most of today’s birds shed their feathers – some up to three times a year – and scientists have long debated whether the flightless dodo did the same.
The new detailed analysis of 22 bones from 22 dodos from fossil sites on the Indian Ocean island nation Mauritius, where the extinct bird was once endemic, reveals the dodo shed its feathers just like modern birds.
The research team, from the University of Cape Town, identified large cavities in the outer shell of the dodo’s bones, or cortex.
This would have been caused by the calcium being absorbed by new feathers – a process seen in 15 modern moulting birds, including penguins and pigeons.
The breeding season started around August with ovulation in females, the research found.
Moulting began around March with the replacement of the feathers of the wings and the tail first.
So at the end of July the moult would have been completed in time for the next breeding season.
The research also sheds new light on the colour of the birds’ feathers at different stages of moulting, and reveals new information on the species’ mating habits and early growth.
Previous evidence for the colour of the flightless birds came in the form of mariners’ paintings from the 17th century, when Europeans first visited Mauritius.
The researchers say they have uncovered the ‘secret life of the dodo’ by exploring its mating behaviour and rapid early growth through fossilised bones. Pictured left and right are sections of hindlimb dodo bones showing resorption cavities which are interpreted as evidence of molt
The research also sheds new light on the colour of the birds’ feathers at different stages of moulting, and reveals new information on the species’ mating habits and early growth
Eye-witness accounts suggested it had grey ostrich-like feathers, cream-coloured wings and tail colour, black quills and a yellow and black beak.
Previous evidence for the colour of the flightless birds came in the form of mariners’ paintings from the 17th century
Painters showed body hues ranging from from light-blue-grey to a grey-brown – suggesting there may have been a difference between male and female birds.
Study coauthor Dr Delphine Angst said: ‘Moulting periods have been previously proposed for the dodo but these are generally unsupported.
‘The dodo was variably described as having three or four black quills in the place of their wings, and a tail with four or five small curled plumes of a greyish colour.
‘Some other descriptions of the dodo mention a clothing of downy feathers or even no feathers on their body, which is instead covered in black down.
‘We propose that mariners may have been describing the dodo at different stages of moult.
Through their study of dodo bones (pictured) the researchers conclude that mariners’ descriptions dodo colours varies because the birds moulted throughout each season, changing colour as their feathers grew
As well as the discovery that dodos moulted, the landmark new study also found the dodo experienced rapid growth rates until it reached sexual maturity. Pictured are yransverse thin sections of a humerus of the dodo
Dodos described as having a downy plumage were probably observed and described just after moult, as seen in some modern moulting birds, Dr Angst said.
The grey or black plumage in some descriptions could correspond to dodo specimens between two moulting periods, she added.
Little is known about the life of the dodo, despite it’s status as one of the world’s most famous extinct species.
The bird gets its name from the Portuguese word for fool after colonialists mocked its apparent lack of fear of human hunters.
The 3ft tall bird was wiped out by visiting sailors and the dogs, cats, pigs and monkeys they brought to the island in the 17th century.
Because the species lived in isolation on Mauritius for millions of years, the bird was fearless, and its inability to fly made it easy prey.
Its last confirmed sighting was in 1662 after Dutch sailors first spotted the species just 64 years earlier in 1598.
The research also sheds new light on the colour of the birds’ feathers at different stages of moulting, and reveals new information on the species’ mating habits and early growth
As well as the discovery that dodos moulted, the landmark new study, published in Scientific Reports, also found the dodo experienced rapid growth rates until it reached sexual maturity.
This is seen in many birds today, including the Japanese quail, the king penguin and the ostrich.
This enabled them to reach a big size to withstand the harsh conditions of the Southern Hemisphere summer and cyclone season from November to March.
Dr Angst said: ‘In the case of the dodo, harsh seasonal conditions on Mauritius exist during the summer months, between November and March.
A detailed analysis of 22 bones from 22 dodos from fossil sites on the Indian Ocean island nation Mauritius, where the extinct bird was once endemic, reveals the dodo shed its feathers just like modern birds
‘During this period, cyclones can occur, during which heavy rain and strong winds can strip trees of leaves, flowers and fruit, causing severe food shortages and starvation for the island fauna, and it can take a few months for normal environmental conditions to return.
‘These events may explain the variations in body mass, as reported by mariners for the dodo.’
The specimens analysed included five thigh bones, 14 shin bones, two toe bones and one wing bone.
The bones belonged to juveniles ranging in age from older juveniles to adults.
At least two were from females, the researchers said, because of the distinctive tissue caused by ovulating birds’ calcium rich egg shells.
Dr Angst said: ‘ This research represents the only microscopic bone analysis of the dodo and provides an unprecedented insight into the life history of this iconic bird.’