Habituation to Auditory Stimuli by Captive African Elephants (Loxodonta africana)

Abstract

Habituation is a major concern for the development of effective, long-term human-wildlife conflict mitigation and zoo enrichment programs. Elephants are cognitive species that exhibit many types of learning, such as associative, social, and insight learning. However, no study has examined the habituation process in elephants. Elephants possess a well-developed sensory system and may habituate to stimuli that could be used for enrichment and/or management. The aim of this study was to examine their habituation process in response to repeated presentations of two auditory stimuli: buzzing by a disturbed beehive and the sound created by banging on pots and pans, and in comparison to no sound trials. The selected sounds often invoke alert behaviors and movements in wild elephants as part of human-elephant conflict mitigation. We predicted that elephants would initially exhibit strong reactions to both sounds, but these responses would diminish over repeated trials. This study was conducted with four female African elephants (Loxodonta africana) at the Nashville Zoo in Tennessee. During the first sound presentation, the elephants reacted by showing distress, avoidance, and vigilance behaviors. Over repeated presentations, their reactions to the sounds diminished to levels observed during the no-sound trials, suggesting habituation had occurred. The elephants also reduced their response to the second sound more rapidly than to the first sound, suggesting that generalization of their habituation had occurred. The results support our hypothesis that elephants use habituation to learn which stimuli are non-threatening and subsequently stop responding to them. Habituation is an important learning process that should be considered during the implementation of captive and wildlife management, especially for highly intelligent species, such as elephants.