Publications

Manes are generally thought to characterize all adult male lions (Panthera leo). Here we document a population of lions in Tsavo National Park, Kenya, that is largely maneless and describe aspects of their social organization. Because Tsavo's arid landscape supports sparse prey populations, we expected that surveys of lions there would document small social groups. We hypothesized that Tsavo lions would consequently experience reduced sexual selection pressures for mane development. Adult males from Tsavo typically have sparse blond hair forming a dorsal crest, beard, chest tufts, and (or) sideburns, but lack the large flowing manes reported from other lion populations. No fully maned lions were seen. Maneless males in Tsavo appear to be well integrated into pride life, and were observed copulating, hunting, and otherwise interacting with groups of females, playing with dependent cubs, and advertising territories with scent markings and roars. Only one adult male was observed in each of five prides, which differs surprisingly from the coalitions of 2–4 pride males noted in other lion groups. However, female group size was large (mean 7.4) and comparable with what has been documented in the Serengeti and elsewhere, refuting our "group size – mane size" hypothesis. Future research should focus on the effect of Tsavo's physical and physiological effects on mane condition, and the possible correlation of male hormone levels with both manelessness and small male-group size.