Mating System: Male-Female Relationships

Elephants have the mating system of hierarchical promiscuity. In this system, many males compete for opportunity to mate with a female in estrous. Estrous is a period of female sexual receptiveness indicated by a series of behavioral characteristics (Moss 1983). The winner is determined by male sexual status and hierarchical status. Additionally, some degree of female choice determines the mating success of males. Females prefer males in musth, a period of heightened sexual and aggressive behavior in males (Moss 1988). Sometimes consort behavior occurs, during which a bull will sexually monopolize and defend a cow during part of her estrous cycle (Moss 1988).
Since the kin group provides female elephants with the resources needed to raise offspring, no resources are needed from the male. Rather than trying to secure resources from a mate, cows have the "he-man strategy" of trying to mate with the male with best genes. Genetic fitness is displayed through sexual status and hierarchical status. Bulls have the reproductive strategy of trying to mate with as many females as possible. It is not advantageous for a male to defend a particular kin group for an extended length of time since a kin group rarely has a female in estrous.
A female normally mates at the age of 13 during her first estrous cycle. Estrous normally occurs for a period of 2 to 6 days (Moss 1983). Estrous periods are not synchronous. The peak period of estrous is after the rainy season (Poole 1989). Musth periods are also not synchronous. It appears that musth in younger males is suppressed by the aggression of older males, and thus is sporadic (Poole 1989). The time of year when a male come sinto musth appears to stay constant from year to year, unless the male gains or loses status. Older males come into musth before associating with females. Younger males came into musth after associating with females for a month or less (Poole 1987). Due to male competition, most bulls do not mate until their mid-twenties (Moss 1982).
In order to find an available mate, most musth males have to travel long distances. Musth calls by bulls and estrous calls by cows are thought to help elephants to find sexual partners over long distances (Poole 1999). When a bull sees a family unit, he will normally greet them, test females for estrous, and leave if there are no females in estrous (Moss 1982).
There are five distinctive behavioral phases of estrous. The first is wariness, with a female not allowing herself to be tested and carrying her head high. The second is the estrous walk, when females walk in an arc around the group followed by one or more males. This walk appears to be initiated by the female. The third is the chase, in which one to several bulls try to catch the female. The female normally stops if a male touches her with his trunk. The fourth phase is mounting in which the pair copulates for around 40 seconds. During copulation the kin group often defecates and urinates while backing towards the pair. The fifth phase is consort behavior. During consort behavior a male stays close to a female and attempts to prevent other males from copulating with her (Moss 1983).
During early and late behavioral estrous, a female is typically pursued by young males and sometimes mates with them. During mid-estrous, a female often has a consort relationship with a male in musth, normally an older male. It appears that some cows exercise a degree of choice in mating. Indeed, only 30% of the chases result in copulation. Evidence suggests that older females select mates more often than younger females. The preference is for males in musth (Moss 1983). Furthermore, some cows in estrous, especially older cows, appeared to solicit guarding from male in musth by affectionately approaching a male (Poole 1989, Moss 1983).