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Extinct Teratorn (Family Teratornithidae) Fact Sheet: Reproduction & Development

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

How Do We Know This?

Isotope studies of elements present fossil bones and tusks in microscopic quantities give information about timing of reproductive stress, and timing of nursing. Clues to stages of development come from tooth replacement patterns and closure of sutures in skull and limb bones.

Life Stages

  • Argentavis estimates calculated by comparison with similar sized modern raptors with long breeding cycles and small clutches. (Palmqvist & Vizcaíno 2003)
    • Breeding every two years
    • Incubation of eggs: 64 days
    • One or two hatchlings every two years
    • Nestlings for 230 days
    • Long period of time to reach maturity, like albatross or frigate birds - at least 10 years.

Mortality and Extinction

  • The largest teratorns probably had a long life span, due to their large size. (Palmqvist & Vizcaíno 2003)
  • Causes of death not known but assumed to be lack of food, disease, parasites, predation by other raptors or owls, and accidents, much like modern birds of prey (Palmqvist & Vizcaíno 2003)

Page Citations

Palmqvist & Vizcaíno (2003)

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