Female reproductive activity and its endocrine correlates in the African lesser bushbaby, Galago moholi.

Steroid hormones play an important role in female reproductive physiology and behaviour and are often used to monitor important female reproductive events. However, such studies are often attempted on captive populations alone, delivering limited data. One such example is the African lesser bushbaby, Galago moholi, for which contradicting observational data exist between captive and free-ranging populations, while hormonal analyses have only been obtained from a single captive population. To extend and rectify the limited information, we monitored faecal progestagen and oestrogen metabolite levels across various important life history stages of both captive and free-ranging G. moholi. We additionally recorded changes in vaginal state as well as the occurrence of reproductive and aggressive behaviour throughout the study. Data from our captive population revealed an ovarian cycle length of 33.44 ± 0.59 days (mean ± SD), with follicular and luteal phases of 14.2 ± 1.0 and 19.1 ± 1.5 days, respectively, and an average pregnancy length of 128 ± 3.3 days. The initiation of female reproductive activity was closely linked to an oestrus-related increase in faecal oestrogen metabolite levels. Four of the seven captive females monitored in our study conceived during the May mating period, with one additional female fertilised in September, supporting the idea that the September mating period functions as a back-up for female G. moholi. Identified benchmark faecal progestagen metabolite levels (non-pregnant: >1 µg/g dry weight (DW), pregnant: >9 µg/g DW) should help researchers to determine pregnancy status of randomly wild-caught females in even a cross-sectional study setup.