tail, which measures in males and in females. The weights reported according to some authors probably underrepresent their size, especially those of full-grown females, and their body size range based on linear dimensions (the weighed birds could have been all smaller males). This species also possesses an exceptional long tarsus, which may rival the Philippine eagle, which weighs about three times more than the Papuan eagle, as the longest of all living eagles at . Meanwhile, the wing chord measures in males and . A single male had a culmen length of . At all ages, Papuan eagles are a greyish brown raptor with a creamy-coloured underside. Adults also have obscure darker bars on the underside. The back bears faint buff and white edging, which in good light can make these areas appear somewhat scaled. The tail is of the same colour as the back with a whitish tip with four or five blackish bands (the subterminal one being broad), which are also present on the cream-colored undertail. The juvenile is similar to the adult, but is of a slightly paler grey-brown colour above with a slightly more buff colouring on the underside. Also, the juvenile's tail has seven or eight narrower bars and no subterminal band. The short but full crest of this species can be conspicuous, while the face may suggest a ruff. The Papuan eagle has rather peculiar proportions, with a prominent head, powerful, large and black bill and cere, large eyes with brown to orange irises, a chesty build, extremely elongated, bare legs of a brownish-grey to dull orange colour, very long tail, and powerful feet with sharp claws. When seen sitting about the ground, it has an upright posture and an almost bustard-like appearance due to its unusual structure. Based on fragmentary data from captivity, both the eye colour and the leg colour may grow more vivid with age, with one record-aged male of 30 years old having red eyes. In flight, the upperside is homogeneously all grey-brown and the underwings are all cream like the underside, but for barred grey but dull flight feathers. Due to its unusual appearance it is unlikely to be mistaken for the other large, widespread New Guinea eagle, Gurney's eagle, a more typical aquiline-type eagle in appearance with significantly different proportions and form as well as clearly much darker dorsal colour (while juvenile Gurney's are far more pale and