The limited availability of resources is predicted to impose trade-offs
between growth, reproduction and self-maintenance in animals. However,
although some studies have shown that early reproduction suppresses
growth, reproduction positively correlates with size in others. We use
detailed records from a large population of semi-captive elephants in
Myanmar to assess the relationships between size (height and weight),
reproduction and survival in female Asian elephants, a species
characterized by slow, costly life history. Although female height gain
during the growth period overlapped little with reproductive onset in
the population, there was large variation in age at first reproduction
and only 81% of final weight had been reached by peak age of
reproduction at the population level (19 years). Those females beginning
reproduction early tended to be taller and lighter later in life,
although these trends were not significant. We found that taller females
were more likely to have reproduced by a given age, but such effects
diminished with age, suggesting there may be a size threshold to
reproduction which is especially important in young females. Because
size was not linked with female survival during reproductive ages, the
diminishing effect of height on reproduction with age is unlikely to be
due to biased survival of larger females. We conclude that although
reproduction may not always impose significant costs on growth, height
may be a limiting factor to reproduction in young female Asian
elephants, which could have important implications considering their
birth rates are low and peak reproduction is young – 19 years in this
population. © 2017 European Society For Evolutionary Biology. Journal of
Evolutionary Biology © 2017 European Society For Evolutionary Biology