A 6,000+ year-old specimen of a spectacled bear from an Andean cave in Peru

Abstract

We report the discovery of a partial skeleton of the oldest spectacled bear (Tremarctos ornatus) known to date. It was found at 2,950 m elevation in the Chaquil cave, in the Departamento de Amazonas, north central Peru. Its age, as determined by accelerated mass spectrometry conventional radiocarbon dating, was, within 50 years, 5,980 years before present (YBP). After a standard correction for Holocene irregularities of atmospheric 14 C (carbon 14) levels, this conventional radiocarbon age translates into a calendar age of about 6,790 years before present. Anatomical features of the skull shows no significant differences from extant spectacled bears. Comparative analysis of Chaquil remains with those of modern specimens revealed some intraspecific variation at the sagittal crest, mandibular ramus and symphysis, masseteric crest, and coronoid process. We suggest that the extremely worn teeth, with the pulpar cavity exposed in the sub-fossil, are related to a primarily carnivorous diet.