Letters to Nature

Nature 393, 680-682 (18 June 1998) | doi:10.1038/31461; Received 22 January 1998; Accepted 23 March 1998

A king-sized theropod coprolite

Karen Chin1, Timothy T. Tokaryk2, Gregory M. Erickson3,4 & Lewis C. Calk1

  1. United States Geological Survey, 345 Middlefield Road, MS 975, Menlo Park, California 94025, USA
  2. Eastend Fossil Research Station, Royal Saskatchewan Museum, Box 460, Eastend, Saskatchewan S0N 0T0, Canada
  3. Department of Integrative Biology & Museums of Vertebrate Zoology and Paleontology, University of California, Berkeley, California 94720, USA
  4. Present address: Biomechanical Engineering Division, Mechanical Engineering Department

Correspondence to: Karen Chin1 Correspondence and requests for materials should be addressed to K.C. (e-mail: Email: kchin@pangea.stanford.edu).

Fossil faeces (coprolites) provide unique trophic perspectives on ancient ecosystems. Yet, although thousands of coprolites have been discovered, specimens that can be unequivocally attributed to carnivorous dinosaurs are almost unknown. A few fossil faeces have been ascribed to herbivorous dinosaurs1, 2, 3, but it is more difficult to identify coprolites produced by theropods because other carnivorous taxa coexisted with dinosaurs and most faeces are taxonomically ambiguous. Thus sizeable (up to 20 cm long and 10 cm wide) phosphatic coprolites from Belgium4 and India5,6 that have been attributed to dinosaurs might have been produced by contemporaneous crocodylians7 or fish. But there is no ambiguity about the theropod origin of the Cretaceous coprolite we report here. This specimen is more than twice as large as any previously reported carnivore coprolite, and its great size and temporal and geographic context indicate that it was produced by a tyrannosaur, most likely Tyrannosaurus rex. The specimen contains a high proportion (30–50%) of bone fragments, and is rare tangible evidence of theropod diet and digestive processes.