Asian elephants exhibit post-reproductive lifespans

Area of Science:

• Evolutionary biology
• Gerontology
• Mammalogy

Background:

• The evolutionary significance of extended post-reproductive lifespan remains debated.
• Post-reproductive representation, the proportion of adult life after reproduction ceases, is a key metric.
• Previous analyses suggested only humans and some toothed whales have extended post-reproductive lifespans.

Purpose of the Study:

• To investigate the presence of an extended post-reproductive lifespan in Asian elephants.
• To examine how the length of demographic data collection impacts estimates of post-reproductive representation.

Main Methods:

• Utilized an extensive demographic dataset from semi-captive timber elephants in Myanmar.
• Analyzed post-reproductive representation over a 50-year period.
• Assessed the sensitivity of demographic rates to data duration.

Main Results:

• Provided evidence supporting an extended post-reproductive stage in Asian elephants.
• Demonstrated that post-reproductive representation and demographic rates are influenced by the study duration.
• Highlighted the dependency of these measures on the length of available long-term data.

Conclusions:

• Extended post-reproductive lifespan in Asian elephants may be driven by mating preferences or fertility linked to physical condition, rather than physiological cessation of reproduction.
• Re-evaluating population measures in long-lived species with extended datasets is crucial.
• The typical lifespan of a species exceeding the initial study period necessitates updated analyses.