A putative Eocene specimen is known from Wyoming, while the more modern Chaunoides antiquus is known from the late Oligocene to early Miocene in Brazil.

Given the presence of lamelae in the otherwise fowl-like beaks of screamers, it is even possible that they evolved from presbyornithid-grade birds, reverting from a filter-feeding lifestyle to an herbivorous one.

They have large spurs on their wings which are used in fights over mates and territorial disputes;[2] these can break off in the breast of other screamers, and are regularly renewed.

They can be excellent guard animals, due to their loud alarm calls ("screams") when encountering anything new and possibly threatening.

[8] They are seldom hunted, in spite of their conspicuous nature, because their flesh has a spongy texture and is riddled with air-sacs, making it highly unpalatable.