Egg Mountain

area, Montana, United States

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July 16, 2026

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Egg Mountain is an area in Montana, United States, significant for its dinosaur fossil discoveries. In 1978, paleontologist John R. Horner and his crews found numerous dinosaur nests, eggs, and newly hatched dinosaurs, primarily duckbills, in upland regions. This contrasted with previous explorations that focused on lowland areas. The discoveries at Egg Mountain provided crucial insights into dinosaur behavior, suggesting that multiple dinosaur species migrated to this location annually for nesting. Evidence of stacked nests indicated that specific species likely returned to the same site year after year, demonstrating "site fidelity" as part of their reproductive strategy.1

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dinosaur
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Egg Mountain, as the area was named, produced some of the most important clues to dinosaurian habits yet found. For example, the sites show that a number of different dinosaur species made annual treks to this same nesting ground (though perhaps not all at the…
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Egg Mountain, as the area was named, produced some of the most important clues to dinosaurian habits yet found. For example, the sites show that a number of different dinosaur species made annual treks to this same nesting ground (though perhaps not all at the…
Read More