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Extinct Teratorn (Family Teratornithidae) Fact Sheet: Distribution & Habitat

Extinct Teratorn (Teratornis merriami, Aiolornis incredibilis, Cathartornis gracilis, Argentavis magnificens) Family Teratornithidae

How Do We Know This?

Paleontologists use knowledge of the earth's rocks, global plate tectonic movements, ancient ecosystems, and the chemical process of fossilization to make sense of fossil distribution patterns and ancient habitats.

Prehistoric Distribution

  • Argentavis magnificens known from central and northwestern Argentina.
  • T. merriami known from about 105 specimens from Rancho La Brea,California, plus Florida, New Mexico, and Mexico
  • Cathartornis gracilis known only from Rancho La Brea, California
  • Ailornis incredibilis found in southern California and Nevada


  • Argentavis: This bird, the largest of the teratorns may have depended on updrafts and thermals to stay aloft (Chatterjee et al 207)
  • Argentavis may have evolved in South America along with the evolution of open grasslands and the rise of the Andes. (Rhys 1980) (Chatterjee et al 2007)
    • Habitat may have been a large plain like southern Patagonia today (savanna with distinct dry season) (Campbell & Tonni 1981) with areas of mountain ranges or high ground for nesting and taking off. (Palmqvist & Vizcaíno 2003) (Chatterjee et al 2007)
    • Home range estimated at 542 km sq (Palmqvist & Vizcaíno 2003)
  • Teratornis merriami occupied habitats that were less open, with coastal shrub and woodlands in California

Page Citations

Campbell & Tonni (1981)
Chatterjee et al. (2007)
Palmqvist & Vizcaíno (2003)
Rhys (1980)

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