Magazine R1 the hunting while the rest just watch. is able to annex particularly valuable Quick guide Communal cub rearing confers landscape. Anna Mosser developed substantial benefits: groups of a map of lion ‘real estate’, based mothers can successfully defend their on localized reproductive rates and Lions cubs against an infanticidal male, found that river confluences were the whereas a lone female has no chance most important landscape features. Craig Packer one-on-one. But most other felids Migratory herbivores are reluctant to — for example, leopards, cougars, cross tributaries because of the risk tigers, bobcats and lynx — are also of ambush and are often funneled What are lions? The largest cats in infanticidal, yet they are all solitary. into the confluences, where lions Africa, lions are about the same size The true hallmark of lion sociality is make most of their kills. Water flow as tigers. Modern lions descend from their joint defense of a territory. Karen also scours riverbeds most deeply the extinct cave lion (Panthera atrox), McComb measured the responses of at confluences, leaving the most which once ranged more widely than females to recorded roars of unfamiliar persistent waterholes and promoting any mammalian species. Modern lions females. A roar is a territorial display, the densest vegetative growth. dispersed from Africa to Asia about and the females responded according Consequently, prides that control the 100,000 years ago, but Asiatic lions to the odds: if a lone female heard most confluences leave the greatest are now restricted to a small part of the roar of a single female, she number of descendants, and larger Gujarat in western India. African lions recruited distant pridemates, but a prides maintain control of the best once ranged from the Atlas Mountains group of three females immediately habitat. to the Cape of Good Hope, but both approached the loudspeaker. When The savannas are the most the Atlas lion and the Cape lion no exposed to a roaring trio, real trios heterogeneous of felid habitats; lions longer exist in the wild. Although there again recruited help, while quintets live at higher densities than other are slight genetic differences between quickly approached. The real females species of big cat and thereby face lions in eastern, western and southern moved to oust the invaders as long the most intense competition for good Africa, all African lions are considered as they outnumbered the strangers by habitat. Thus only lions can benefit to belong to the same subspecies. at least two individuals. Jon Grinnell from banding together and defending Lions prefer prey that range in found a similar sense of ‘numeracy’ highly valuable landscape features. size from goat-sized gazelle to Cape in males, but they sometimes buffalo. Litter size is typically two or approached even when outnumbered Why do male lions have manes? three cubs; offspring are weaned by three to one — probably because The mane may either serve to shield 6–8 months but remain dependent males have such a brief opportunity to a male’s neck during fights with on their mothers for about two father offspring and must protect their other males or to indicate the male’s years. Females first give birth at the pride at all costs. ‘quality’. The mane is unlikely to be age of 3–4 years and show marked Possessing a high quality a shield, as neck wounds are no reproductive decline by the age of 14 territory is essential for successful more common than on other parts years. Males typically start breeding reproduction, and as a pride grows it of the body nor are neck wounds by 4-5 years. In the wild, maximum lifespan is 19 years for females and 15 years for males. Uniquely among felids, female lions form stable social groupings (‘prides’) of up to 22 females. Male lions form coalitions of up to 10 males that may control several prides, either simultaneously or sequentially. Male lions are also unique among felids for growing conspicuous manes. Lions are the best-studied big cat species, being the focus of long- term research in Tanzania, Kenya, Botswana, Namibia, South Africa and Zimbabwe, with additional studies in Benin, Cameroon, Ghana, Mozambique and Zambia. Why do lions live in groups? The traditional explanation for lion sociality has been cooperative hunting, but lions do not hunt as cooperatively as believed. Consequently, individual Figure 1. A gang attack on during an intergroup encounter in Serengeti lions. lions do not always feed better in Lions are at their most cooperative when fighting against outsiders. Females form prides to larger groups, because a single defend joint territories; males form coalitions to gain exclusive access to female prides. (Photo: group member often does most of Ingela Jansson.) Current Biology Vol 20 No 14 R2 more likely to be fatal — even in km2). Lions are well managed in South females and maneless sub-adult Africa where the parks and reserves males. Instead, the mane appears are all fenced, but fencing the national to indicate ‘quality’: males may lose parks in the rest of sub-Saharan their manes after being seriously Africa seems infeasible. Lions along injured, and dark-maned males Namibia’s Skeleton Coast and in have higher testosterone levels, are Zimbabwe’s Save Valley Conservancy more likely to recover from physical were rescued from near elimination injury and their offspring have better by intensive conservation efforts, but survival. Thus, mane length indicates recovery in Namibia led to renewed recent fighting success, and mane conflicts with local people. Intensive color conveys information about efforts to engage pastoralists in lion male aggressiveness and potential conservation in Kenya are so far reproductive success. Peyton West successful, but only protect a few set out pairs of life-sized toy lions that dozen lions; to remain genetically differed in either mane length or mane viable, a population should number at color. Males approached the ‘weaker’ least a thousand. member of the pair as indicated by a Faced with these trends, the long- shorter or lighter mane. In contrast, term future of the lion is bleak. African females were indifferent to mane countries are reluctant to place length, but were much more attracted restrictions on trophy hunting, human to dark manes than to blonds. populations continue to grow, wildlife Variation in a sexually selected trait habitat continues to shrink, Chinese generally results from the inherent influence in Africa is expanding, costs of expressing such elaborate funding for national parks is shrinking, physical characteristics so that only and the costs of conserving even a the highest-quality males can carry single lion are growing. In the long- the most exaggerated traits. Infrared term, the lion seems doomed to the thermography revealed that maned same fate as the tiger or the panda, male lions suffer greater heat stress except for a few well-protected areas than females, and males with darker like the Serengeti or Kruger. manes are hotter than males with blond manes. Consistent with these Where can I find out more? findings, males with darker manes Antunes, A., J.L., Troyer, M.E., Roelke, J., Pecon- Slattery, C., Packer, C., Winterbach, H., have higher proportions of defective Winterbach, G., Hemson, L., Frank, P., Stander, sperm, and eat relatively small meals L., et al. (2008).The evolutionary history of lion: Integrating host/pathogen molecular genetics. in hotter weather. These costs are PLoS Genet 4, e1000251. doi:10.1371/journal. burdens that only superior males can pgen.1000251 bear; for inferior males, a dark mane Grinnell, J., Packer, C., and Pusey, A.E. (1995). Cooperation in male lions: kinship, reciprocity would inflict physiological costs that or mutualism? Anim. Behav. 49, 95–105. outweighed the reproductive benefits. IUCN. (2006) Conservation Strategy for the lion (Panthera leo) in Eastern and Southern Africa, http://www.felidae.org/JOBURG/Lion_E_ What is the future of the lion? Sweb1.pdf. Habitat loss has restricted lions to McComb, K.E., Packer, C., and Pusey, A.E. (1994) Roaring and numerical assessment in contests 10% of their former range, and many between groups of female lions Panthera leo. of the surviving populations face Anim. Behav. 47, 379–387. Mosser, A., and Packer, C. (2009). Group intense conflicts with rural villagers. territoriality and the benefits of sociality in the Substantial numbers of lions are killed African lion, Panthera leo. Anim. Behav. 78, each year in retaliation for livestock 359–370. Packer, C. (2009). Rational fear. Nat. Hist. 119, depredation and man-eating. Lions 43-47. are an important trophy species for Packer, C., Scheel, D., and Pusey, A.E. (1990). Why lions form groups: food is not enough. Am. Nat. the sport-hunting industry but have 136, 1–19. been seriously over-harvested in Packer, C., Kosmala, M., Cooley, H.S., Brink, H., most countries. There is considerable Pintea, L., Garshelis, D., Purchase, G., Strauss, M., Swanson, A., Balme, G., et al. (2009). Sport demand for lion parts in Nigeria and hunting, predator control and conservation growing concern that lion bones may of large carnivores. PLoS ONE 4, e5941. doi:10.1371/journal.pone.0005941. replace tiger bones in traditional West, P.M. and Packer, C. (2002). Sexual selection, Chinese medicine. temperature and the lion’s mane. Science 297, Conservation efforts are dwarfed 1339–1343. by the lions’ enormous range Department of Ecology, Evolution and requirements (individuals can disperse Behavior University of Minnesota, 1987 > 400 km), and the large size of key Upper Buford Circle, St. Paul, MN 55108. reserves (for example, Tanzania’s USA. E-mail: [email protected] Selous Game Reserve is ~55,000 .