Dodo
The dodo is an extinct flightless bird that was endemic to Mauritius, an island east of Madagascar in the Indian Ocean. The dodo's closest relative was the also-extinct and flightless Rodrigues solitaire. The two formed the subtribe Raphina, a clade of extinct flightless birds that are a part of the group that includes pigeons and doves. 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 it is now believed that this assumption was merely confusion based on the also-extinct Réunion ibis and paintings of white dodos.
Subfossil remains show the dodo measured about in height and may have weighed in the wild. The dodo's appearance in life is evidenced only by drawings, paintings, and written accounts from the 17th century. Since these portraits vary considerably, and since only some of the illustrations are known to have been drawn from live specimens, the dodos' exact appearance in life remains unresolved, and little is known about its behaviour. 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. Though the dodo has historically been portrayed as being fat and clumsy, it is now thought to have been well-adapted for its ecosystem.
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 the bird to be a myth. In the 19th century, research was conducted on a small quantity of remains of 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 less than a century after 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.
Taxonomy
The dodo was variously declared a small ostrich, a rail, an albatross, or a vulture, by early scientists. In 1842, Danish zoologist Johannes Theodor Reinhardt proposed that dodos were ground pigeons, based on studies of a dodo skull he had discovered in the collection of the Natural History Museum of Denmark. This view was met with ridicule, but was later supported by English naturalists Hugh Edwin Strickland and Alexander Gordon Melville in their 1848 monograph The Dodo and Its Kindred, which attempted to separate myth from reality. After dissecting the preserved head and foot of the specimen at the Oxford University Museum and comparing it with the few remains then available of the extinct Rodrigues solitaire, they concluded that the two were closely related. Strickland stated that although not identical, these birds shared many distinguishing features of the leg bones, otherwise known only in pigeons.Strickland and Melville established that the dodo was anatomically similar to pigeons in many features. They pointed to the very short keratinous portion of the beak, with its long, slender, naked basal part. Other pigeons also have bare skin around their eyes, almost reaching their beak, as in dodos. The forehead was high in relation to the beak, and the nostril was located low on the middle of the beak and surrounded by skin, a combination of features shared only with pigeons. The legs of the dodo were generally more similar to those of terrestrial pigeons than of other birds, both in their scales and in their skeletal features. Depictions of the large crop hinted at a relationship with pigeons, in which this feature is more developed than in other birds. Pigeons generally have very small clutches, and the dodo is said to have laid a single egg. Like pigeons, the dodo lacked the vomer and septum of the nostrils, and it shared details in the mandible, the zygomatic bone, the palate, and the hallux. The dodo differed from other pigeons mainly in the small size of the wings and the large size of the beak in proportion to the rest of the cranium.
Throughout the 19th century, several species were classified as congeneric with the dodo, including the Rodrigues solitaire and the Réunion solitaire, as Didus solitarius and Raphus solitarius, respectively. An atypical 17th-century description of a dodo and bones found on Rodrigues, now known to have belonged to the Rodrigues solitaire, led Abraham Dee Bartlett to name a new species, Didus nazarenus, in 1852. Based on solitaire remains, it is now a synonym of that species. Crude drawings of the red rail of Mauritius were also misinterpreted as dodo species; Didus broeckii and Didus herberti.
For many years the dodo and the Rodrigues solitaire were placed in a family of their own, the Raphidae, because their exact relationships with other pigeons were unresolved. Each was also placed in its own monotypic family, as it was thought that they had evolved their similarities independently. Osteological and DNA analysis has since led to the dissolution of the family Raphidae, and the dodo and solitaire are now placed in the columbid subfamily Raphinae and tribe Raphini, along with their closest relatives. In 2024, the new subtribe Raphina was created to include only the dodo and the solitaire.
Evolution
In 2002, American geneticist Beth Shapiro and colleagues analysed the DNA of the dodo for the first time. Comparison of mitochondrial cytochrome b and 12S rRNA sequences isolated from a tarsal of the Oxford specimen and a femur of a Rodrigues solitaire confirmed their close relationship and their placement within the Columbidae. The genetic evidence was interpreted as showing the Southeast Asian Nicobar pigeon to be their closest living relative, followed by the crowned pigeons of New Guinea, and the superficially dodo-like tooth-billed pigeon from Samoa. This clade consists of generally ground-dwelling island endemic pigeons. The following cladogram shows the dodo's closest relationships within the Columbidae, based on Shapiro and colleagues, 2002:File:Oxford Dodo foot.jpg|thumb|right|1848 lithograph of the Oxford specimen's foot, which has been used to sample DNA for genetic analyses
A similar cladogram was published in 2007, inverting the placement of Goura and Didunculus and including the pheasant pigeon and the thick-billed ground pigeon at the base of the clade. The DNA used in these studies was obtained from the Oxford specimen, and since this material is degraded, and no usable DNA has been extracted from subfossil remains, these findings still need to be independently verified. Based on behavioural and morphological evidence, Jolyon C. Parish proposed that the dodo and Rodrigues solitaire should be placed in the subfamily Gourinae along with the Goura pigeons and others, in agreement with the genetic evidence. In 2014, DNA of the only known specimen of the recently extinct spotted green pigeon was analysed, and it was found to be a close relative of the Nicobar pigeon, and thus also the dodo and Rodrigues solitaire.
The 2002 study indicated that the ancestors of the dodo and the solitaire diverged around the Paleogene-Neogene boundary, about 23.03 million years ago. The Mascarene Islands, are of volcanic origin and are less than 10 million years old. Therefore, the ancestors of both birds probably remained capable of flight for a considerable time after the separation of their lineage. The Nicobar and spotted green pigeon were placed at the base of a lineage leading to the Raphinae, which indicates the flightless raphines had ancestors that were able to fly, were semi-terrestrial, and inhabited islands. This in turn supports the hypothesis that the ancestors of those birds reached the Mascarene islands by island hopping from South Asia. The lack of mammalian herbivores competing for resources on these islands allowed the solitaire and the dodo to attain very large sizes and flightlessness. Despite its divergent skull morphology and adaptations for larger size, many features of its skeleton remained similar to those of smaller, flying pigeons. Another large, flightless pigeon, the Viti Levu giant pigeon, was described in 2001 from subfossil material from Fiji. It was only slightly smaller than the dodo and the solitaire, and it too is thought to have been related to the crowned pigeons.
Etymology
One of the original names for the dodo was the Dutch "Walghvoghel", first used in the journal of Dutch Vice Admiral Wybrand van Warwijck, who visited Mauritius during the Second Dutch Expedition to Indonesia in 1598. Walghe means "tasteless", "insipid", or "sickly", and voghel means "bird". The name was translated by Jakob Friedlib into German as Walchstök or Walchvögel. The original Dutch report titled Waarachtige Beschryving was lost, but the English translation survived:Another account from that voyage, perhaps the first to mention the dodo, states that the Portuguese referred to them as penguins. The meaning may not have been derived from penguin, but from pinion, a reference to the small wings. The crew of the Dutch ship Gelderland referred to the bird as "Dronte" in 1602, a name that is still used in some languages. This crew also called them "griff-eendt" and "kermisgans", in reference to fowl fattened for the Kermesse festival in Amsterdam, which was held the day after they anchored on Mauritius.
File:Lophopsittacus.mauritianus.jpg|thumb|alt=Crude sketch of three terrestrial birds, captioned with the words "a Cacato, a Hen, a Dodo"|Labelled sketch from 1634 by Sir Thomas Herbert, showing a broad-billed parrot, a red rail, and a dodo
The etymology of the word dodo is unclear. Some ascribe it to the Dutch word dodoor for "sluggard", but it is more probably related to Dodaars, which means either "fat-arse" or "knot-arse", referring to the knot of feathers on the hind end. The first record of the word Dodaars is in Captain Willem Van West-Zanen's journal in 1602. The English writer Sir Thomas Herbert was the first to use the word dodo in print in his 1634 travelogue claiming it was referred to as such by the Portuguese, who had visited Mauritius in 1507. Another Englishman, Emmanuel Altham, had used the word in a 1628 letter in which he also claimed its origin was Portuguese. The name "dodar" was introduced into English at the same time as dodo, but was only used until the 18th century. As far as is known, the Portuguese never mentioned the bird. Nevertheless, some sources still state that the word dodo derives from the Portuguese word doudo, meaning "fool" or "crazy". It has also been suggested that dodo was an onomatopoeic approximation of the bird's call, a two-note pigeon-like sound resembling "doo-doo".
The Latin name cucullatus was first used in 1635 by the Spanish Jesuit Juan Eusebio Nieremberg as Cygnus cucullatus, in reference to Carolus Clusius's 1605 depiction of a dodo. In the tenth edition of his 18th-century classic work Systema Naturae, the Swedish naturalist Carl Linnaeus used cucullatus as the specific name, but combined it with the genus name Struthio. Mathurin Jacques Brisson coined the genus name Raphus in 1760, resulting in the current name Raphus cucullatus. In 1766, Linnaeus coined the new binomial Didus ineptus. This has become a synonym of the earlier name because of nomenclatural priority.