Harem (zoology)

The term harem is used in zoology to distinguish social organization consisting of a group of females, their offspring, and one to two males. The single male, called the dominant male, may be accompanied by another young male, called a "follower" male. Females that closely associate with the dominant male are called "central females," while females who associate less frequently with the dominant male are called "peripheral females." Juvenile male offspring leave the harem and live either solitarily, or, with other young males in groups known as bachelor herds. Sexually mature female offspring may stay within their natal harem, or may join another harem. The females in a harem may be, but are not exclusively, genetically related. For instance, the females in hamadryas baboon harems are not usually genetically related because their harems are formed by "kidnapping" females from other harems and subsequent herding. Multiple harems may assemble into larger groups known as "clans" or "teams". Harem cohesiveness is mediated by the dominant male who fights off invading males to keep claim over the harem. Because time and resources are no longer being devoted to the offspring, infanticide often stimulates the female to return to sexual receptivity and fertility sooner than if the offspring were to survive. Furthermore, while lactating, females do not ovulate and consequently are not fertile. Infanticide therefore has the potential to increase the incoming male's reproductive success. == Benefits ==

Harems are a beneficial social structure for the dominant male, as it allows him access to several reproductively available females at a time. == Costs ==

Harems can prove energetically costly for both males and females. Males spend substantial amounts of energy engaging in battles to invade a harem, or to keep hold of a harem once dominance has been established. In this strategy, a male sneaks in to mate while the harem owner is distracted: in the case of red deer, when the harem stag is involved in a fight with another older stag. The strategy is also recorded in other species such as the elephant seal. ==Examples==

Animals that form harems include: Mammals • Red deer • Elephant seal • Greater short-nosed fruit bat • Jamaican fruit bat Primates • Hamadryas baboon • Gorillas Birds • Boat-tailed grackle • Common pheasant • Greater rhea Insects • Bark beetle • Tree wētā • Malaysian stalk-eyed fly forms temporary harems even though mating frequency is high with multiple mating partners. Fish • Hogfish • Several species of cichlid • California sheephead == References ==