page_title: Gastrolith
hierarchical_section_title: Gastrolith
caption_attribution_description: Psittacosaurus gastroliths
context_page_description: Gastroliths, or gizzard stones, are small rocks kept by an animal inside its stomach or at an early part of the alimentary canal. The function of these is to mash up the food so digestion takes place faster. Typically, animals which do this do not have suitable teeth for grinding, and the gastroliths are a good substitute for this.
  A second function, in aquatic animals, is that gastroliths can be used for ballast to make diving easier.
context_section_description: Gastroliths, or gizzard stones, are small rocks kept by an animal inside its stomach or at an early part of the alimentary canal. The function of these is to mash up the food so digestion takes place faster. Typically, animals which do this do not have suitable teeth for grinding, and the gastroliths are a good substitute for this. 
  A second function, in aquatic animals, is that gastroliths can be used for ballast to make diving easier.
caption: Psittacosaurus fossil with gastroliths in its stomach region, American Museum of Natural History
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