Plant feeding of yellow baboons (Papio cynocephalus) in Mikumi National Park, Tanzania, and the relationship between seasonal feeding and immature survival

A road traversing a protected area has little effect on feeding and foraging behaviour of yellow baboons

“…Although time spent feeding and foraging by yellow baboon is highly influenced by availability and distribution of food patches as well as troop size, the fact that baboons spent relatively similar proportion of time feeding and foraging in different habitats (Table 2) implies that, no matter the difference in vegetation, feeding occupies higher percent of the activity budget of yellow baboons. Such finding has been widely documented in studies related to feeding and foraging behavior of other baboon species (Cowlishaw, 1996; Hill & Dunbar, 2002; Norton et al, 1987; Post, 1982; Rhine et al, 1989; Whiten et al, 1991). The lower proportion of feeding in the riverine forests is influenced by the nature of its vegetation (mostly ditches and trees), which is mostly suitable for sleeping and drinking rather than foraging.…”

“…Because of reproduction role of female and continuous growing of subadult males, they both require higher quality diet (Isbell et al, 2013). Thus, females tend to supplement their fruit diet with arthropods, which are higher in protein and fats compared with leaves (Rhine et al, 1989; Rothman et al, 2014). Subadult males tend to suppliant their fruit diet with plant exudates because it is rich in carbohydrates and some minerals (Garber, 1984; Porter et al, 2009), hence provide much needed energy for growth.…”

Breeding seasonality generates reproductive trade-offs in a long-lived mammal

“…For example, chacma baboons and humans share a generalist diet (27), a capacity to extract fall-back foods at times of food scarcity (40), and an ability to store energy (2,4), which have likely played a critical role in their adaptation to breed year-round in seasonal environments (41,42). The few studies that have investigated the effects of birth timing on early survival of offspring in non-seasonal breeding primates such as geladas (Theropithecus gelada) (43) have indeed failed to detect any effect.…”

“…Late-weaning is most critical for infants who must learn to ensure their own provisioning. Matching that stage with the most productive season may substantially enhance infant survival (26,27,49,50). Moreover, the peak of lactation typically coincides with the onset of weaning, and matching it with abundant resources can help to accelerate the transition to feeding independence by granting infants access to a wealth of weaning foods (Figure 1B) (26).…”

“…Second, the duration of maternal IBI is influenced by the timing of the birth opening the IBI (Table S1): females giving birth between August st and September th had the shortest IBIs (Table S2), indicating another different optimal birth timing for maternal reproductive pace in the annual cycle (Figure 2B). In the first case, the birth timing that maximises offspring survival synchronizes the seasonal food peak with the end of weaning, a highly vulnerable life stage for mammals (26)(27)(28), which occurs between 12 and 18 months after birth in this population (Figure 1B). In the second case, the birth timing that maximizes maternal reproductive pace synchronizes the food peak with the peak of lactation (occurring around 6 months after birth) (Figure 1B), which is the most energetically-costly reproductive stage for mothers (3,26), and may therefore help to alleviate the costs of lactation and enhance maternal condition during the second half of lactation.…”