English

Etymology

Taken from gastro-, meaning stomach, and -lith, related to stone.

Noun

1. In the context of "zoology": rocks which are or have been held inside the digestive tract of an animal to aid in buoyancy or food processing.

Gastroliths ('stomach stones' or 'gizzard stones') are rocks, which are or have been held inside the digestive tract of an animal. Among living vertebrates, gastroliths are common among herbivorous birds, crocodiles, alligators, seals and sea lions. Domestic fowl, for instance, require access to 'grit', for the purpose of food-grinding. Gastroliths are retained in the very muscular gizzard and serve the masticatory function of teeth, in an animal without suitable grinding teeth. The grain size of the gastrolith depends upon the size of the animal and its special needs. Particles as small as sand and stones the size of cobbles or greater have been found.

• Coprolite

References

Whittle, C. (1989). On the Origins of Gastroliths: Determining the Weathering Environment of Rounded and Polished Stones by Scanning Electron Microscope Analysis. Geological Society of America Bulletin 51:5.

Whittle, C. (1988). On the Origins of Gastroliths. Journal of Vertebrate Paleontology, Supplement to 3:28.

• Wings, Oliver (2003): Observations on the Release of Gastroliths from Ostrich Chick Carcasses in Terrestrial and Aquatic Environments. Journal of Taphonomy 1(2): 97-103. PDF fulltext

• Wings, Oliver (2004): Identification, distribution, and function of gastroliths in dinosaurs and extant birds with emphasis on ostriches (Struthio camelus). Ph.D. Thesis, The University of Bonn, Bonn, Germany, 187 pp. URN: urn:nbn:de:hbz:5N-04626 PDF fulltext

• Wings, Oliver (2007): A review of gastrolith function with implications for fossil vertebrates and a revised classification. Acta Palaeontologica Polonica 52(1): 1-16. PDF fulltext

• Wings, Oliver & Sander, P.M. (2007): No gastric mill in sauropod dinosaurs: new evidence from analysis of gastrolith mass and function in ostriches. Proc. R. Soc. B 274(1610): 635–640. PDF fulltext