Extinct Teratorn (Family Teratornithidae) Fact Sheet: Summary

Kingdom: Animalia

Phylum: Chordata

Class: Aves

Order: Accipitirformes - includes hawks, eagles, vultures (or Ciconiiformes - includes storks, herons); taxonomy at this level uncertain

Family: Teratornithidae (extinct family of prehistoric birds)

Genus: Teratornis

Species: Teratornis merriami (Miller, 1909) - Merriam's Teratorn (extinct)

Genus: Aiolornis

Species: Aiolornis incredibilis (Howard, 1952; new combination by Campbell) - Incredible Teratorn (extinct)

Genus: Cathartornis

Species: Cathartornis gracilis (Miller, 1910) - Slender Teratorn (extinct)

Genus: Argentavis

Species: Argentavis magnificens (Campbell & Toni, 1980) - Magnificent Argentine Teratorn (extinct)

Estimated Body Weight
Teratornis merriami: 13.7 kg (30.2 lb); slightly heavier than living California Condor
Ailornis incredibilis: 23 kg (50 lb)
Argentavis magnificens: 70 kg (154 lb); 7 times heavier than California Condor

Estimated Wingspan
Teratornis merriami: 3.5-4 m (11.5-13.1 ft)
Ailornis incredibilis: 5.0-5.5 m (16.4-18 ft)
Argentavis magnificens: 6-8 m (19.7-26.3 ft)

Habitat
Argentavis: dependent on geography that created updrift thermals (e.g., mountains and associated grasslands)
Teratornis: less open habitats, such as coastal shrub and woodlands in California

Status
No members of the teratorn family survived Pleistocene times; they have been extinct for at least 10,000 years.

Locomotion
Walking and soaring flight.

Interspecies Interactions
Likely interactions with other daytime raptors and scavengers.

Diet
Carnivorous; also scavenged on carrion.
Armadillos, rodent-like mammals, possums, and capybara may have been food for Argentavis magnificens.
Lizards, snakes, small and medium-sized mammals, and birds may have been food for Teratornis merriami.

Predators
Not well understood; possibly other raptors.

Breeding
May have had breeding cycles similar to similar-sized modern day raptors. Reproduction characterized small clutchs (1-2 eggs per clutch), 2-3 year breeding cycles, and long nestling periods.

Longevity
Largest teratorns probably had a long life span.

Feature Facts

• Large, soaring, predatory and scavenging (extinct) birds
• Probably hunted during the day, using thermals for flight
• Teratornis merriami able to move well on the ground
• Argentavis magnificens could have swallowed hare-sized prey in one gulp.