BACKGROUND The existence of extended post-reproductive lifespan is an evolutionary puzzle, and its taxonomic prevalence is debated. One way of measuring post-reproductive life is with post-reproductive representation, the proportion of adult years lived by females after cessation of reproduction. Analyses of post-reproductive representation in mammals have claimed that only humans and some toothed whale species exhibit extended post-reproductive life, but there are suggestions of a post-reproductive stage for false killer whales and Asian elephants. Here, we investigate the presence of post-reproductive lifespan in Asian elephants using an extended demographic dataset collected from semi-captive timber elephants in Myanmar. Furthermore, we investigate the sensitivity of post-reproductive representation values to availability of long-term data over 50 years. RESULTS We find support for the presence of an extended post-reproductive stage in Asian elephants, and that post-reproductive representation and its underlying demographic rates depend on the length of study period in a long-lived animal. CONCLUSIONS The extended post-reproductive lifespan is unlikely due to physiological reproductive cessation, and may instead be driven by mating preferences or condition-dependent fertility. Our results also show that it is crucial to revisit such population measures in long-lived species as more data is collected, and if the typical lifespan of the species exceeds the initial study period.

中文翻译：

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亚洲象表现出繁殖后的寿命。

背景延长生殖后寿命的存在是一个进化难题，其分类学普遍性也存在争议。衡量生育后寿命的一种方法是生育后代表性，即女性停止生育后存活的成年年龄的比例。对哺乳动物繁殖后表现的分析表明，只有人类和一些齿鲸物种表现出延长的繁殖后寿命，但有人建议假虎鲸和亚洲象存在繁殖后阶段。在这里，我们使用从缅甸半圈养的木材象收集的扩展人口数据集来调查亚洲象繁殖后寿命的存在。此外，我们还研究了生殖后代表性值对 50 年来长期数据可用性的敏感性。结果我们发现亚洲象存在延长的繁殖后阶段，并且繁殖后代表性及其基本人口比率取决于长寿动物的研究期长度。结论 生殖后寿命的延长不太可能是由于生理性生殖停止所致，而可能是由交配偏好或条件依赖性生育力驱动的。我们的结果还表明，随着收集更多数据，并且如果物种的典型寿命超过最初的研究期限，重新审视长寿物种的种群数量至关重要。