Differences in age-specific mortality between wild-caught and captive-born Asian elephants

Area of Science:

• Wildlife conservation science
• Animal welfare studies
• Demographic analysis of wildlife populations

Background:

• Wild-capture is prevalent for various purposes, yet its long-term impacts on animal mortality remain poorly understood.
• Asian elephants are frequently captured for timber work, making them a key species for studying capture effects.
• Existing data on the consequences of wild-capture, particularly for long-lived species, is limited.

Purpose of the Study:

• To investigate the long-term mortality consequences of wild-capture in Asian elephants.
• To compare mortality rates between wild-captured and captive-born elephants.
• To assess how age at capture influences long-term survival.

Main Methods:

• Utilized exceptional demographic records of 5150 Asian elephants from Myanmar timber camps (1951-2000).
• Analyzed mortality data in relation to capture status (wild-captured vs. captive-born).
• Examined the influence of age at capture and sex on post-capture mortality trends.

Main Results:

• Wild-captured elephants exhibited significantly higher mortality than captive-born elephants.
• The detrimental effects of capture on mortality were observed across both sexes.
• Elephants captured at older ages demonstrated a greater increase in mortality risk compared to those captured young.
• Elevated mortality risk persisted for several years following capture and taming.

Conclusions:

• Wild-capture has severe and lasting negative impacts on Asian elephant survival.
• Age at capture is a critical factor influencing the severity of post-capture mortality.
• Findings underscore the need for caution in wild-capture practices, especially given global wild population declines.