Self-directed behavior reflects social stress in captive Asian elephants

Area of Science:

• Ethology
• Animal Welfare Science
• Behavioral Ecology

Background:

• Self-directed behaviors (SDBs) are established indicators of anxiety and social stress in non-human primates.
• Research on SDBs in non-primate species, like Asian elephants (Elephas maximus), is limited but crucial for welfare assessments and comparative studies.

Purpose of the Study:

• To investigate if SDB levels in Asian elephants reflect experienced social stress.
• To identify specific SDBs associated with post-conflict situations and varying social stress levels.
• To explore the relationship between SDBs and stereotypic behaviors in captive elephants.

Main Methods:

• Employed all-occurrences and focal sampling on four captive Asian elephants.
• Compared post-conflict SDB levels to individual baselines.
• Analyzed changes in SDBs in relation to victimization rates and group composition changes.

Main Results:

• A significant increase in SDB levels was observed in elephants post-aggression compared to baseline levels (39.8% increase in counts, p=0.024).
• Specific SDBs like 'touch mouth', 'head shake', 'dust bathing', and 'trunk curled inwards' showed significant changes (p<0.05).
• Individual baseline SDBs correlated with victimization rates, with one individual showing significantly lower SDBs when not a victim.

Conclusions:

• Specific self-directed behaviors are induced by social stress in Asian elephants.
• SDBs show potential as reliable indicators of social stress and wellbeing in Asian elephants.
• Findings support the expansion of SDB research to non-primate species for enhanced animal welfare.