Great bustard it well camouflaged in open habitats. Immature birds resemble the female. The eastern subspecies ("O. t. dybowskii") is more extensively grey in colour in both sexes, with more extensive barring on the back. The great bustard has long legs, a long neck and a heavy, barrel-chested body. It is fairly typical of the family in its overall shape and habitat preferences. Three other bustard species overlap in range with this species: the Macqueen's ("Chlamydotis macqueenii"), houbara ("Chlamydotis undulata") and little bustards ("Tetrax tetrax"). However, none of these attains the plumage coloration nor approach the body sizes of this species. Thus,
Porphyria cutanea tarda the body. Certain mutations in the "HFE" gene cause hemochromatosis (an iron overload disorder). People who have these mutations are also at an increased risk of developing porphyria cutanea tarda. In the 20% of cases where porphyria cutanea tarda is inherited, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to decrease enzyme activity and cause the signs and symptoms of the disorder. While inherited deficiencies in uroporphyrinogen decarboxylase often lead to the development of PCT, there are a number of risk factors that can both cause and exacerbate the symptoms