The dodo was an extraordinary animal that has always been a part of popular culture. Although there are no living specimens left , films like Alice in Wonderland, Ice Age or Up have recreated its appearance, although the truth is that scientists have never had much information about this creature. While this distant relative of pigeons has long been extinct – the common dodo became extinct around 1670 and the last of the white dodo died in 1761 – details about its life now seem to come alive more than ever.
For the first time, a team of researchers from the University of Cape Town in South Africa has reconstructed the complete life cycle of these legendary birds.
The dodo evolved to adapt to the seasonal climate cycles of the islands of Mauritius . For these extraordinary birds, the challenge was to survive the food shortage typical of a harsh and dry season such as the austral summer, between November and March. But, once the lean season is over, the birds would begin to shed their feathers , replacing the damaged ones.
“We have discovered that, by the month of July, they would have developed a completely new plumage,” details lead researcher Delphine Angst. ” In August, the females began to ovulate and lay eggs, which were born in September, allowing the young to grow fast enough to survive another southern summer,” he specified.
A secret hidden in the bones
Angst and his colleagues elaborated the cycle by analyzing the structure and composition of 22 bones from 22 dodos. All the bones were from the hind legs, except one of them.
According to the results of the analyzes, published in the journal Scientific Reports, the bones of the youngest dodos were abnormally rich in fibrolamellar bone , which contains many immature bone cells that allow the bird to grow rapidly.
In contrast, other bones, belonging to adult dodos, had large cavities that corresponded to the molting cycle. “To produce new feathers, birds need more calcium , and the cavities show that this calcium was being extracted from the bones,” explains the lead author of the study.
The discovery that dodos had a molting cycle also helps explain why sailors visiting Mauritius reported different versions of them in their description of dodos.
“There are records of dodos with black plumage , which probably coincides with the beginning of the molting season. Others described dodos as a mixture of soft plumage and royal feathers. Lastly, there are descriptions of dodos covered entirely by royal feathers, probably corresponding to birds that had completed the cycle, “says Angst.
But there is still more. The team has also managed to identify differences between males and females.
In two bones, which have been identified with a female specimen, a complementary tissue, called medullary bone, has been found, which is a vital source of calcium for the manufacture of eggshells. This fabric is exclusive to females. The two female bones were similar in size to the other bones in his sample, which tends to refute an earlier idea that male and female dodo specimens were very different in their adult sizes.
The common dodo ( Raphus cucullatus ), which lived in the Mauritius Islands; and the white dodo, ( Pezophaps solitaria ), which nested on the neighboring island of Reunion, were exterminated by humans, within the first 100 years after European sailors arrived and colonized Mauritius in the 16th century.
Image: Julian Hume
Reference:
Bone histology sheds new light on the ecology of the dodo (Raphus cucullatus, Aves, Columbiformes). D. Angst, A. Chinsamy, L. Steel & JP Hume. Scientific Reports 7, Article number: 7993 (2017). Doi: 10.1038 / s41598-017-08536-3e
