“Apart from mane traits, lions exhibit no sexual selection.”

Lions display sexually selected infanticide, and resident males must defend their offspring from nomads that may have dispersed over long distances; factors affecting male–male competition over large spatial scales can have population wide consequences.

Mane darkness indicates nutrition and testosterone and influences both female choice and male-male competition. … Mane length signals fighting success and only appears to influence male-male assessment.

An age-based mate choice was observed in lionesses: maiden breeders chose males having highest range overlaps, whereas experienced females selected peripheral males.

Among the myriad ideas inaugurating sociobiology in the 1970s, the hypothesis that infanticide is a male strategy that improves reproductive success at the expense of female fitness ([Hrdy 1974](#A017640C114)) constituted one of the first demonstrations of the "battle of the sexes" theory … Compelling evidence for sexually selected infanticide in the nonprimate mammals has come from field studies of fissiped carnivores (particularly bears and well-studied lions) … There are several lines of evidence that group living among lionesses (*Panthera leo*) is an effective deterrent to infanticide ([Packer and Pusey 1983](#A017640C170)). Cub mortality is much lower for females living in groups of two or more than for solitary mothers ([Pusey and Packer 1994b](#A017640C205)).

These two factors appear to elicit competition between male coalitions for control of the pride, with the result that larger coalitions eventually become resident.

Male lions form cooperative coalitions which compete against other coalitions for exclusive access to female groups1,2. … However, we now present evidence that breeding coalitions of male lions include non-relatives much more commonly than was generally supposed, that intra-coalition competition over females is widespread and that kinship is not the primary factor determining levels of competition.

Mane darkness indicates nutrition and testosterone and influences both female choice and male-male competition. Mane length signals fighting success and only appears to influence male-male assessment.

Male lions in large coalitions gain reproductive advantages.

Alternatively, the lion's mane may simply be ornamental and mate choice may be the primary evolutionary force, as suggested by the finding that females preferentially move toward model male lions with darker manes (West & Packer, 2002).

African lions (Panthera leo; lions hereafter) are territorial animals that live in social groups (prides) composed of related females and a coalition of males ("pride males" hereafter) that compete with other coalitions for exclusive access to females (Bygott et al., 1979; Schaller, 1972) .

To investigate the sexual selection hypothesis of infanticide for lions, four questions should be considered: (1) because they all mate freely with lionesses, are male pride lions closely related? (often they are not), (2) do males kill the young cubs when they join a pride? (few such cases have been observed), (3) do the females then mate with the new males to produce offspring? (yes), and (4) do the males remain with the pride for over two years to protect this new generation? (often not).

These strategies include aggression, female choice of dominant males, and promiscuity to confuse paternity as defense against males, and territoriality, association with kin, reproductive suppression, and reproductive synchrony as defenses against females.

Contrasting availability of resources between Gir and Serengeti/Ngorongoro helps explain the varying degrees of sexual segregation and appears to drive differences in mating systems between these lion populations.

Poorly maned but fully mature lions mated actively, showing dissociation between mane development and sexual maturity.

Mane darkness indicates nutrition and testosterone and influences both female choice and male-male competition. … Mane length signals fighting success and only appears to influence male-male assessment.

The bottom line is that this social system provides op portunities for sexual selection based on male-male competition and mate choice.

Charles Darwin was the first to suggest that the mane may be a result of sexual selection, meaning that the mane increases reproductive success. … Thus the lion’s mane appears to be a sexually selected signal by which a male advertises his quality to other lions.

At the same time, however, females show heightened sexual activity, being more active in initiating copulations and seeking a greater number of mating partners. These 2 factors appear to elicit competition between male coalitions for control of the pride, with the result that larger coalitions eventually become resident.

Mane darkness indicates nutrition and testosterone and influences both female choice and male-male competition. … Mane length signals fighting success and only appears to influence male-male assessment.

Mane darkness indicates nutrition and testosterone and influences both female choice and male-male competition. Mane length signals fighting success and only appears to influence male-male assessment.

Sexual dimorphism in canine size is related to the breeding system, and a greater inter-male competition, such as that found in polygynous group-living species, seems to result in a greater canine dimorphism in primates (Harvey, Kavanagh & Clutton-Brock, 1978) and in carnivores (Gittleman & Van Valkenburgh, 1997). … Therefore, although not conclusive, the results are compatible with the proposal that late Pleistocene lions possessed a breeding system similar to that of modern lions –a male (or a coalition of males) reproductively monopolizing female pride(s) under appropriate conditions –in other words, they may have lived in groups in the evolutionary context.

Mane darkness indicates nutrition and testosterone and influences both female choice and male-male competition. Mane length signals fighting success and only appears to influence male-male assessment.