Asian elephants exhibit post-reproductive lifespans
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. A...
Published in: | BMC Evolutionary Biology |
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Main Authors: | , , , , |
Format: | Text |
Language: | English |
Published: |
BioMed Central
2019
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Subjects: | |
Online Access: | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6805341/ http://www.ncbi.nlm.nih.gov/pubmed/31638893 https://doi.org/10.1186/s12862-019-1513-1 |
Summary: | 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. |
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