STRUCTURAL COLOUR: STAR SPECIES NUMBER 9
Special Power: To return from the dead?
The dodo (Raphus cucullatus) is an extinct flightless bird that was endemic to the island of Mauritius, east of Madagascar in the Indian Ocean. The closest living relative of the dodo is the Nicobar pigeon. A white dodo was once thought to have existed on the nearby island of Réunion, but this is now thought to have been confusion based on the Réunion ibis and paintings of white dodos.
Museum remains show us that the dodo was about 1 metre (3 ft 3 in) tall and may have weighed 10.6–17.5 kg (23–39 lb) in the wild. The dodo’s appearance in life is evidenced only by drawings, paintings, and written accounts from the 17th century. As these vary considerably, and only some of the illustrations are known to have been drawn from live specimens, its exact appearance in life remains unresolved, and little is known about its behaviour. Though the dodo has historically been considered fat and clumsy, it is now thought to have been well-adapted for its ecosystem. It has been depicted with brownish-grey plumage, yellow feet, a tuft of tail feathers, a grey, naked head, and a black, yellow, and green beak. It used gizzard stones to help digest its food, which is thought to have included fruits, and its main habitat is believed to have been the woods in the drier coastal areas of Mauritius. One account states its clutch consisted of a single egg. It is presumed that the dodo became flightless because of the ready availability of abundant food sources and a relative absence of predators on Mauritius.
The first recorded mention of the dodo was by Dutch sailors in 1598. In the following years, the bird was hunted by sailors and invasive species, while its habitat was being destroyed. The last widely accepted sighting of a dodo was in 1662. Its extinction was not immediately noticed, and some considered it to be a mythical creature. In the 19th century, research was conducted on a small quantity of remains from four specimens that had been brought to Europe in the early 17th century. Among these is a dried head, the only soft tissue of the dodo that remains today. Since then, a large amount of subfossil material has been collected on Mauritius, mostly from the Mare aux Songes swamp. The extinction of the dodo within less than a century of its discovery called attention to the previously unrecognised problem of human involvement in the disappearance of entire species. The dodo achieved widespread recognition from its role in the story of Alice’s Adventures in Wonderland, and it has since become a fixture in popular culture, often as a symbol of extinction and obsolescence.
And yet, we may still see the Dodo …
Scientists in Sheffield are currently working with feathers from the Tradescant Dodo, a specimen held in the Oxford Museum of Natural History which is the only source of original dodo feathers in existence. Unlike the paintings and etchings of dodos (see image above) that were almost all created by artists who never visited Mauritius or, indeed, who never saw a living dodo, the Tradesecant dodo was a living specimen brought back to England in the 17th Century and – after its death – eventually incorporated into the Ashmolean Museum in Oxford.
An eye-witness account from the time describes an encounter with a captive dodo during 1638. In this account the writer describes the bird as being ‘coloured like the breast of a young cock fesan and on the back of a dunn or deark colour.’
Recent analysis of granules of the pigment melanin, derived from the feathers from the Tradescant Dodo, confirm that the dodo was, at least in part, grey (or dunn or deark) in colour.
What is most intriguing to researchers into structural colour, however, is the comparison to the ‘breast of a young cock fesan’. As the notable impressionist painter Monet discovered, pheasant feathers are extremely difficult, if not impossible, to render in pigment owing to their iridescent nature. Perhaps this is because of the presence of photonic structures in the feathers – structures that might have given the dodo a vibrant, iridescent shine?