Rules for roving males

Among some species of mammals, females are gregarious and males do not defend spatial territories. In such cases, males may either rove between groups of females searching for receptive females or remain resident with a particular group of females. Under some conditions, males would be expected to obey the general rule of remaining resident with groups of females if the travel time between encountering groups of females is greater than the oestrous period of a female, or otherwise roving between these groups. This rule holds when female group size and the rate at which females enter oestrus vary slowly, but identically, for all groups; when several males may consort with a female but successful paternity is unpredictable; and when a linear dominance hierarchy determines access to disputed females. However, when the first male to consort with a female is successful, resident behaviour is more favoured. In all these cases all males should try to adopt the same strategy at any time. If female group size varies, or females within groups synchronize their oestrus, or males can anticipate female receptivity, then males should remain with groups where there is a high immediate probability of successful matings, and leave those where it is lower. In these situations the tendency to remain within groups will be generally greater at the end of the breeding season.