Using personality ratings and cortisol to characterize individual differences in African Elephants (Loxodonta africana)

Abstract

The development of indices to assist in the management of captive animals and assess their well-being is a key priority for those responsible for providing care to animals in captivity, including the zoological community. In particular, the design of indices for use with some of the more charismatic and socially complex animals, such as African elephants is a major focus. The use of personality ratings and/or cortisol measurements has become a common tool for managing farm animals and is gaining popularity within zoos. However, a combined behavioral and physiological approach has not been examined in captive African elephants (Loxodonta africana). We sought to characterize African elephants using serum and salivary cortisol measurements and our Elephant Behavior Index, a personality rating system modified from an index designed for nonhuman primates. Subjects were five adult female African elephants housed at Disney's Animal Kingdom®. Each subject was rated on the Elephant Behavior Index, which consisted of 23 personality adjectives on a 5-point scale, by 16 raters familiar with the elephants. Saliva and blood samples were collected for cortisol analyses. Reliability across raters for the Elephant Behavior Index was established and correlations between the 23 ratings revealed four components of elephant personality: fearful, effective, sociable and aggressive. Salivary and serum cortisol were correlated and the afternoon decline in cortisol that has been documented in a variety of species was detected for both salivary and serum cortisol (morning salivary –M=0.038, SD=0.012; morning serum –M=2.147, SD=1.305; afternoon salivary –M=0.020, SD=0.008; afternoon serum –M=0.445, SD=0.251). We found positive correlations between morning cortisol levels and the fearful component and negative correlations between cortisol and effective, sociable and aggressive components. Our study demonstrated how personality ratings and cortisol can be utilized to assess individual characteristics of African elephants. Determining these unique characteristics will allow caregivers to tailor management protocols to the meet the needs of individual elephants.