When Sharks Swam the Great Plains

PBS Eons2 minutes read

The Western Interior Seaway existed from 95 to 68 million years ago, hosting various predators like sharks, mosasaurs, and plesiosaurs with niche partitioning to reduce competition. Evidence of interactions between predators, fossilized stomach contents, and fossil-bearing limestones in the Great Plains serve as reminders of this ancient sea.

Insights

  • The Western Interior Seaway, existing 95 to 68 million years ago, divided North America into Appalachia and Laramidia, showcasing a diverse ecosystem of predators like sharks, mosasaurs, and plesiosaurs.
  • Niche partitioning among predators in the Western Interior Seaway led to the evolution of different hunting methods, diets, and habitats, reducing competition and allowing for coexistence over millions of years.

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Recent questions

  • What creatures lived in the Western Interior Seaway?

    Predators like sharks, mosasaurs, and plesiosaurs.

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Summary

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Ancient Sea Predators of Western Interior

  • The Western Interior Seaway existed from 95 to 68 million years ago, running from the Caribbean Sea to the Canadian Arctic.
  • The formation of the Western Interior Seaway began around 180 million years ago due to the Farallon Plate subducting under North America.
  • Rising sea levels from the mid-Cretaceous to the early Eocene led to the connection of the Arctic Ocean and the Gulf of Mexico, dividing North America into Appalachia and Laramidia.
  • The Western Interior Seaway was home to various predators, including sharks, mosasaurs, and plesiosaurs, coexisting for millions of years.
  • Niche partitioning allowed predators in the Western Interior Seaway to evolve different hunting methods, diets, and habitats to reduce competition.
  • Body size, anatomy, and habitat differences among predators in the Western Interior Seaway helped reduce competition for prey.
  • Fossilized stomach contents reveal the diet preferences of predators, with larger predators like Tylosaurus going after bigger prey and smaller predators like Platecarpus focusing on fish.
  • Evidence shows interactions between predators in the Western Interior Seaway, with teeth marks from sharks found on various marine reptiles and other predators.
  • The Western Interior Seaway began receding around 80 million years ago due to geologic uplift, leaving behind fossil-bearing limestones that are now used in building materials.
  • The remnants of the Western Interior Seaway can still be seen in the Great Plains, with limestone buildings in central Kansas containing Cretaceous seashells, serving as monuments to the ancient sea.
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