Data from: Is bigger better? The relationship between size and reproduction in female Asian elephants

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.Reproductive data of female Asian elephantsThis data includes repeated height (cm) and weight (kg) measures of 150 individuals, identified by an ID number, with recorded age at measurement, and reproductive data. This reproductive data includes reproductive status at the age of measurement, and the number of calves born to a female and survived to the age of 5. This also includes their 5 year birth cohort, birth origin (1=wild caught, 0=captive born), and age at capture if wild caught (captive born age at capture=0)reproduction_dryad.csvSurvival of female Asian elephantThis data includes height (cm) measures of 104 female Asian elephants aged 20-50, along with their censorship status (1=dead, 0=alive), and their age at censorship or death. This also includes their reproductive status, their birth origin (1=wild caught, 0=captive born), and their age at capture if they are wild caught (captive born age at capture= 0).survival_data_dryad.cs