[4][1] The rufous crab hawk was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[5] Gmelin based his description on the "Aequinoctial eagle" that had been described in 1781 by the English ornithologist John Latham from a specimen that formed part of a private collection in London.

[6] The rufous crab hawk is now one of nine species placed in the genus Buteogallus that was introduced in 1830 by the French naturalist René Lesson.

[9][10] The rufous crab hawk is found on Trinidad and on the South American mainland along the coast from the Orinoco Delta in Venezuela through the Guianas and into Brazil as far as the southeastern state of Paraná.

It primarily inhabits mangroves but also occurs in swamps, wet savanna, and river edges near the coast, all essentially at sea level.

[11] It catches them with a short dive from a low perch; it typically takes them to a favored site like a stump to consume them.

Its breeding season varies geographically, for example between February and August in Suriname and apparently from September onward in southeastern Brazil.