Composition and Seasonality of Diet in Wild Hamadryas Baboons: Preliminary Findings from Filoha

Abstract

Here we report the first year-round quantitative data on dietary composition and seasonality in wild hamadryas baboons. Study subjects were adult male members of band 3 at the Filoha field site in central lowland Ethiopia. Data collection consisted of 10-min focal samples during all-day follows 4–6 days per month over the course of 1 year. The two largest contributors to the diet were Hyphaene thebaica and Acacia senegal, and these were the only plant species found in the diet during every month of the year. Other relatively major contributors to the diet, such as Cyperus grandibulbosus, Seddera bagshawei, Tribulus cistoides and Typhalatifolia, showed a seasonal pattern. Fewer plant species were consumed during the dry months of the year compared to the wet months. During the hottest and driest months of the year, study subjects subsisted almost exclusively on H. thebaica, A. senegal, C. grandibulbosus and T.latifolia. Overall, these patterns suggest that this population of hamadryas baboons spends less time feeding and is able to subsist on a narrower array of plant foods compared to other baboons. This pattern may be driven by the presence at Filoha of the doum palm (H. thebaica), a high-quality food resource that is consumed year-round.

Isotopic evidence for an early shift to C4resources by Pliocene hominins in Chad

“…The semiarid terrestrial flora that today stretches away from the current Lake Chad and colonizes the dunes includes Hyphaene thebaica (doum palm), Acacia nilotica, and Ficus ingens (42), all of which produce widely consumed fruits and pods (e.g., refs. [35][36][37][38]. The presence of Giraffa in the KT sites suggests that similar species might have been present in the Pliocene environment.…”

“…34), so the potential value of these resources for hominins has been neglected (see 28). Nevertheless, East African savanna baboons regularly exploit all of the above-ground, fresh parts of taxa such as Cynodon and Sporobolus on a seasonal basis (26,(35)(36)(37)(38). The more nutritious and lower fiber grass meristems may be exploited year-round (36,37).…”

“…today (36)(37)(38)43). Ethnohistoric sources suggest that Cyperus usitatus, Cyperus fulgens, and C. esculentus were important plant resources for Late Stone Age foragers in the semiarid South African Karoo (44).…”

“…The above-ground parts of many sedges are also eaten. For instance, humans use the culms of C. papyrus as casual or famine foods (43) and baboons the flowers and bulbs of Cyperus grandibulbosus (38).…”

“…Savanna baboons are a notable exception as they spend significant amounts of time foraging for C 4 plants (26,(35)(36)(37)(38), although the sparse existing δ 13 C data for these baboons in East Africa show a lower reliance on such resources than one might expect based on foraging time. Bone collagen and enamel values for modern Papio anubis individuals (n = 3, respectively) suggest C 4 contributions of <20% in East Turkana and Naivasha (45) and ∼50% in Laikipia (46).…”