9 - Life-history and Reproductive Strategies of Bats


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Publication Date

December 2000


The timing and frequency of reproduction are major determinants of life-history strategies, which have evolved to maximize lifetime reproductive output, and thus to maximize fitness in terms of an individual's genetic contribution to the next generation. Bats have distinctive life-history strategies for mammals of their size. Most small animals have evolved a “live fast - die young” strategy, characterized by rapid reproduction and high mortality. In contrast, bats generally have a life history characterized by longevity with multiple reproductive events, low litter size and delayed onset of sexual maturity. Typically a single young is produced, although twins are common in some species. The trend for smaller mammals to generally produce relatively larger young reaches its extreme in bats, in which the neonate may weigh up to 43% of maternal mass. Coupled with one of the lowest mass-specific fetal growth rates recorded within mammals, bats are characterized by long gestation lengths for mammals of their size. This is followed by a relatively long period of lactation and post-natal care. Longer gestation, coupled with a shorter period of lactation, may reflect lower energetic investment per day in gestation, compared to the high costs of lactation, and may represent a strategy by which energetic investment in young is optimized in relation to seasonal food abundance.


Bats, Reproductive Strategies Of Bats, Bat Reproduction