The use of 65Zn for estimating group size of brown hyaenas Hyaena brunnea

Abstract

The applicability of a method of estimating group size based on the labelling of an individual within a group of hyaenas with the zinc isotope ⁶⁵Zn is evaluated. This isotope is detectable in faeces and the method is based on the assumption that the proportion of labelled faeces found at latrines, will equal the proportion of labelled hyaenas in the group. Group size estimates increased logarithmically with an increase in the number of stools included in the analysis but remained relatively constant after approximately 140 stools were included. Estimates were in agreement with direct observations.