Terror Bird (Phorusrhacos)

A male Phorusrhacos bird of prey watches over a colony of nesting females during the Miocene Era.
Corey Ford/Stocktrek Images / Getty Images


Terror Bird; also known as Phorusrhacos (Greek for "rag bearer"); pronounced FOE-roos-RAY-cuss


Plains of South America

Historical Epoch:

Middle Miocene (12 million years ago)

Size and Weight:

About eight feet tall and 300 pounds



Distinguishing Characteristics:

Large head and beak; claws on wings


About the Terror Bird (Phorusrhacos)

Phorusracos isn't known as the Terror Bird only because that's much easier to pronounce; this flightless prehistoric bird must have been utterly terrifying to the small mammals of middle Miocene South America, in light of its enormous size (up to eight feet tall and 300 pounds), clawed wings, and heavy, crushing beak. Extrapolating from the behavior of a similar (but much smaller) relative, Kelenken, some paleontologists believe the Terror Bird grabbed its quivering lunch with its talons, then grasped it between its powerful jaws and bashed it repeatedly on the ground to cave in its skull. (It's also possible that the giant beak of Phorusrhacos was a sexually selected characteristic, males with bigger beaks being more attractive to females during mating season.)

Ever since the discovery of its type fossil in 1887, Phorusrhacos has gone by a bewildering number of now-outmoded or reassigned names, including Darwinornis, Titanornis, Stereornis, and Liornis. As for the name that stuck, that was bestowed by a fossil hunter who assumed (from the size of the bones) that he was dealing with a megafauna mammal, and not a bird--hence the lack of the tell-tale "ornis" (Greek for "bird") at the end of the Terror Bird's genus name (Greek for "rag bearer," for reasons that remain mysterious). By the way, Phorusrhacos was closely related to another "terror bird" of the Americas, Titanis, a comparably sized predator that went extinct at the cusp of the Pleistocene epoch--to the extent that a minority of experts classify Titanis as a Phorusrhacos species.

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Strauss, Bob. "Terror Bird (Phorusrhacos)." ThoughtCo, Apr. 5, 2023, thoughtco.com/terror-bird-phorusrhacos-1093597. Strauss, Bob. (2023, April 5). Terror Bird (Phorusrhacos). Retrieved from https://www.thoughtco.com/terror-bird-phorusrhacos-1093597 Strauss, Bob. "Terror Bird (Phorusrhacos)." ThoughtCo. https://www.thoughtco.com/terror-bird-phorusrhacos-1093597 (accessed June 8, 2023).