Many of the skeletal features that distinguish the dodo and the Rodrigues solitaire, its closest relative, from pigeons have been attributed to their flightlessness.
The pelvic elements were thicker than those of flighted pigeons to support the higher weight, and the pectoral region and the small wings were paedomorphic, meaning that they were underdeveloped and retained juvenile features.
The skull, trunk and pelvic limbs were peramorphic, meaning that they changed considerably with age.
The dodo shared several other traits with the Rodrigues solitaire, such as features of the skull, pelvis, and sternum, as well as their large size.
It differed in other aspects, such as being more robust and shorter than the solitaire, having a larger skull and beak, a rounded skull roof, and smaller orbits.
The dodo's neck and legs were proportionally shorter, and it did not possess an equivalent to the knob present on the solitaire's wrists.

As no complete dodo specimens exist, its external appearance, such as plumage and colouration, is hard to determine.
Illustrations and written accounts of encounters with the dodo between its discovery and its extinction (1598–1662) are the primary evidence for its external appearance.
According to most representations, the dodo had greyish or brownish plumage, with lighter primary feathers and a tuft of curly light feathers high on its rear end.
The head was grey and naked, the beak green, black and yellow, and the legs were stout and yellowish, with black claws.
Subfossil remains and remnants of the birds that were brought to Europe in the 17th century show that they were very large birds, 1 metre (3.3 feet) tall, and possibly weighing up to 23 kilograms (51 lb).
The higher weights have been attributed to birds in captivity; weights in the wild were estimated to have been in the range 10.6–21.1 kg (23–47 lb).
A later estimate gives an average weight as low as 10.2 kg (22 lb).
This has been questioned, and there is still some controversy.
It has been suggested that the weight depended on the season, and that individuals were fat during cool seasons, but less so during hot.
The bird was sexually dimorphic: males were larger and had proportionally longer beaks.
The beak was up to 23 centimetres (9.1 in) in length and had a hooked point.
A study of the few remaining feathers on the Oxford specimen head showed that they were pennaceous (vaned feathers with barbs and quills) rather than plumaceous (downy) and most similar to those of other pigeons.

The beak of the solitaire was slightly hooked, and its neck and legs were long.
One observer described it as the size of a swan.
The skull was 170 millimetres (6.7 in) long, flattened at the top with the fore and hind parts elevated into two bony ridges structured with cancellous.
A black band (a contemporary description described it as a "frontlet") appeared on its head just behind the base of the beak.
The plumage of the Rodrigues solitaire was described as grey and brown.
Females were paler than males and had light-coloured elevations on the lower neck.
Sexual size dimorphism in the solitaire is perhaps the greatest in any neognath.
One group, probably the males, were considerably larger than the other, measuring 90 cm (35 in) in length and weighing up to 28 kg (62 lb), whereas the smaller group, probably females, were only 70 cm (28 in) and weighed 17 kg (37 lb).
This is only 60% of the weight of a larger individual.
Their weight may have varied substantially due to fat cycles, meaning that individuals were fat during cool seasons, but slim during hot seasons, and may have been as low as 21 kg (46 lb) in the larger gender and 13 kg (29 lb) in the smaller.
Though male pigeons are usually larger than females, there is no direct evidence for the largest specimens actually being the males of the species, and this has only been assumed based on early works.
Though the male was probably largest, this can only be confirmed by molecular sexing techniques, and not skeletal morphology alone.
Many of the skeletal features that distinguish the dodo and the Rodrigues solitaire, its closest relative, from pigeons have been attributed to their flightlessness. The pelvic elements were thicker than those of flighted pigeons to support the higher weight, and the pectoral region and the small wings were paedomorphic, meaning that they were underdeveloped and retained juvenile features. The skull, trunk and pelvic limbs were peramorphic, meaning that they changed considerably with age. The dodo shared several other traits with the Rodrigues solitaire, such as features of the skull, pelvis, and sternum, as well as their large size. It differed in other aspects, such as being more robust and shorter than the solitaire, having a larger skull and beak, a rounded skull roof, and smaller orbits. The dodo's neck and legs were proportionally shorter, and it did not possess an equivalent to the knob present on the solitaire's wrists.
As no complete dodo specimens exist, its external appearance, such as plumage and colouration, is hard to determine. Illustrations and written accounts of encounters with the dodo between its discovery and its extinction (1598–1662) are the primary evidence for its external appearance. According to most representations, the dodo had greyish or brownish plumage, with lighter primary feathers and a tuft of curly light feathers high on its rear end. The head was grey and naked, the beak green, black and yellow, and the legs were stout and yellowish, with black claws. Subfossil remains and remnants of the birds that were brought to Europe in the 17th century show that they were very large birds, 1 metre (3.3 feet) tall, and possibly weighing up to 23 kilograms (51 lb). The higher weights have been attributed to birds in captivity; weights in the wild were estimated to have been in the range 10.6–21.1 kg (23–47 lb). A later estimate gives an average weight as low as 10.2 kg (22 lb). This has been questioned, and there is still some controversy. It has been suggested that the weight depended on the season, and that individuals were fat during cool seasons, but less so during hot. The bird was sexually dimorphic: males were larger and had proportionally longer beaks. The beak was up to 23 centimetres (9.1 in) in length and had a hooked point. A study of the few remaining feathers on the Oxford specimen head showed that they were pennaceous (vaned feathers with barbs and quills) rather than plumaceous (downy) and most similar to those of other pigeons.
The beak of the solitaire was slightly hooked, and its neck and legs were long. One observer described it as the size of a swan. The skull was 170 millimetres (6.7 in) long, flattened at the top with the fore and hind parts elevated into two bony ridges structured with cancellous. A black band (a contemporary description described it as a "frontlet") appeared on its head just behind the base of the beak. The plumage of the Rodrigues solitaire was described as grey and brown. Females were paler than males and had light-coloured elevations on the lower neck. Sexual size dimorphism in the solitaire is perhaps the greatest in any neognath. One group, probably the males, were considerably larger than the other, measuring 90 cm (35 in) in length and weighing up to 28 kg (62 lb), whereas the smaller group, probably females, were only 70 cm (28 in) and weighed 17 kg (37 lb). This is only 60% of the weight of a larger individual. Their weight may have varied substantially due to fat cycles, meaning that individuals were fat during cool seasons, but slim during hot seasons, and may have been as low as 21 kg (46 lb) in the larger gender and 13 kg (29 lb) in the smaller. Though male pigeons are usually larger than females, there is no direct evidence for the largest specimens actually being the males of the species, and this has only been assumed based on early works. Though the male was probably largest, this can only be confirmed by molecular sexing techniques, and not skeletal morphology alone.
Raphinae