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We investigated the causes and consequences of crop-raiding for the ecology and life-history of two troops of olive baboons studied in Nigeria’s Gashaka Gumti National Park over 8 years. Kwano troop feeds entirely on wild foods whilst the Gamgam troop regularly consumes crops grown within its home-range. Crop-raiding provides both energetic and reproductive advantages as Gamgam troop spent less time travelling and feeding and more time resting and socialising. The crop-raiding troop has also shorter inter-birth intervals and lower infant mortality. Costs to crop-raiding due to chasing and attacks by farmers are outweighed by the benefits of increased access to high-quality foods, a reduced susceptibility to pathogen loads, and a consequently increased reproductive output.

Our long-term study of baboons in Gashaka Gumti National Park (GGNP) is one of very few that looks at West African baboons, and is also unusual because it focuses on animals living in a forested environment with high annual rainfall. Here, we present data on troop size, activity budgets, ranging behaviour, diet, and life-history, and compare these data with those from other baboon study sites. The troop sizes at GGNP are significantly smaller than many other baboon populations, and this may be linked to low predation pressure at the site. The high productivity and floral diversity at GGNP allow animals to avoid eating difficult to process subterranean foods and feed on preferred foods such as fruits and seeds. The diet of wild-feeding animals at the site is diverse, and includes a high proportion of fruit and low proportion of leaves, subterranean items, and animal foods when compared with other baboon populations. Gestation length, cycle length, and length of post-partum amenorrhea for the wild-feeding K troop are typical of baboons but the inter-birth interval in this population is significantly longer than that found in most other baboon populations due to a long duration of cycling. The high rainfall at GGNP may increase disease risk, forcing wild-feeding mothers to invest heavily in their offspring, resulting in a long period of cycling before successful pregnancy and hence a long inter-birth interval.