Hard-Object Feeding in Sooty Mangabeys (Cercocebus atys) and Interpretation of Early Hominin Feeding Ecology Daegling, David J. ; McGraw, W. Scott ; Ungar, Peter S. ; Pampush, James D. ; Vick, Anna E. ; Bitty, E. Anderson Abstract Publication: PLoS ONE Pub Date: August 2011 DOI: 10.1371/journal.pone.0023095 Bibcode: 2011PLoSO...623095D