Summary
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Chimpanzees are a socially diverse and often aggressive member of the Great Apes. They appear small in size than a human yet are usually stronger. They reside in a multitude of African countries and prefer humid and deciduous environments. Due to rapid deforestation they are forced to now live in more varied habitats, including the savanna. Chimpanzees eat a large variety of fruits, nuts, and even insects and meat. Hunting techniques are often deliberated social ventures, though they only rarely are faced with an opportunity to eat meat. Communication techniques include facial expressions, tactile encounters, and vocalizations (Goodall, 1986).
Larger communities make up the overriding social organization, but fusion-fission groups exist within these communities and are often changing (Goodall, 2001). Differences in food availability or the number of females in estrus may affect the fluctuation of such smaller groups. Males are generally more gregarious than females and tend to form more social bonds with one another in comparison to the more independent, wandering female (Goodall, 1986). Interactions between males and females are mostly limited to her state of estrus (Matsumoto-Oda, 1999). When she is estrus, she will usually join groups and integrate with other chimpanzees more. Dominance hierarchies exist among both males and females, though they are more ambiguous within the female population. Among the males hierarchies are based most prominently on age and a clear alpha male is often established (Goodall, 1986). Aggression plays a large part in the lives of chimpanzees, and young chimpanzees usually engage in playfighting techniques as part of their development (Paquette, 1994). Infanticide is the practice of males killing infants from neighboring communities, perhaps to expand the boundaries of their own communities (Watts, et al., 2002).
Chimpanzees live in large overlapping home ranges that may not have clearly defined boundaries. Their food supply is irregularly distributed and they must constantly travel to find enough food. Within this home range males do defend a core classical territory, however. Their territory is often aggressively defended by patrols executed by the males (Goodall, 1986).
No regular breeding season exists for the chimpanzees (Pankopf, 2000). When a female comes into estrus every four to six weeks, she is often mated by many males in a promiscuous fashion. Males will engage in courtship behaviors to attract and entice females to mate with them. Sometimes the alpha male will use aggression to monopolize a female in estrus. Other males sometimes overcome this barrier to one female by forming consortships with other females and leading them to secluded areas on the periphery of the home range (Goodall, 1986).
Helping behaviors include sharing food and assisting in fighting off attackers. Sharing food usually occurs between mothers and their young offspring as well as among a possessor of meat and any chimp who begs. Both kin and non-kin will help each other against an attacker, probably because the chimps are familiar with each other and have formed strong social bonds (Goodall, 1986).