Behaviour 2019
Gelada mothers spend less time feeding during pregnancy if birth is timed to peak
Sofia C. Carrera1, Amy Lu2, Jacinta C. Beehner1. 1University of Michigan, Ann Arbor, MI, United States; 2Stony Brook University, Stony Brook, NY, United States

Birth seasonality results when ecological factors limit a female’s ability to successfully reproduce. Even non-seasonal species often exhibit a birth peak that times a critical stage to an opportune time. The question is whether females that give birth outside this peak (“off-peak”) face energetic consequences. Here, we examine one possible cost, feeding time, in a non-seasonal primate, the gelada (Theropithecus gelada), which has a slight birth peak. We investigated the time females spent feeding based on whether they were “peak” or “off-peak” mothers. We analyzed female behavior during 37 pregnancies (from 2013-2017). Overall, compared to cycling, pregnant females increased feeding time in the second half of pregnancy by 20% (W=283, p=0.01). However, during early pregnancy, “off-peak” mothers spent 20-45% more time feeding compared to “peak” mothers (W=29, p< 0.01).  These results suggest that “off-peak” mothers might suffer higher metabolic costs than “peak” mothers. With increasing research into the effects of the early-life environment, this difference in birth timing could indicate an adverse environment for developing offspring.

Funding: NSF: DGE 1256260