Reproduction is driven by seasonal environmental variation in an equatorial mammal, the banded mongoose (Mungos mungo)

Reproduction is an energetically costly activity and so is often timed to
occur when conditions are most favourable. However, human-induced changes
in long-term, seasonal, and short-term climatic conditions have imposed
negative consequences for reproduction across a range of mammals. Whilst
the effect of climate change on reproduction in temperate species is well
known, its effect on equatorial species is comparatively understudied. We
used long-term ecological data (~20 years) to investigate the impact of
changes in rainfall and temperature on reproduction in an equatorial
mammal, the banded mongoose (Mungos mungo). After controlling for the
effects of group-size, we found that more females were pregnant and gave
birth following periods of high seasonal rainfall, pregnancies increased
at higher seasonal temperatures, and births increased with long-term
rainfall. This is likely beneficial as high rainfall is positively
associated with pup growth and survival. Females cannot, however, carry
and raise pups over the course of a single wet season, so females face a
trade-off in reproductive timing between maximising resource availability
during gestation or the early life of pups, but not both.  Since
the duration of the wet seasons is predicted to increase with climate
change, the optimum conditions for banded mongoose reproduction may be
extended. However, the potential benefits of extended wet seasons may be
counteracted by the negative impacts of high temperatures on pup growth
and survival. Our results highlight the importance of seasonality in
reproduction of tropical mammals and the complex impacts of anthropogenic
climate change on recruitment in equatorial species.