Ecology

Bonobos are found exclusively in the central portion of the Congo Basin, south of the Congo River in the Democratic Republic of Congo. These endangered primates can be found in a variety of habitats, including tropical rainforests, swamp forests, and forest/savanna mosaics (Takemoto,Kawamoto, & Furuich, 2015). Like chimpanzees, bonobos share a complicated relationship between members of their own species and other organisms. Bonobos also have a sophisticated and unique social hierarchy in which the sharing of nutritional resources between group members is not uncommon (Ihobe, 1992). Unlike chimpanzee social organization, bonobo communities are very cooperative and some of the strongest social bonds can be found between the females of a given population (de Waal, 1995).

In contrast to chimpanzees, a male bonobo's status is dependent on the social ranking of that particular male's mother, to whom that male remains socially bonded to until her expiration (de Waal, 1995). Chimpanzees, on the other hand, are prone to stronger social bonds between males, a social adaptation that reinforces the ability of chimpanzees to hunt and guard territory (de Waal, 1995). In chimpanzee structures, females live in their own territories that overlap with male-dominated territory and are not robustly bonded to other females or males (de Waal, 1995). Among bonobos, there are three types of social groups. These consist of groups between mothers and offspring, social groups between females, and social groups between males and females. Social structures associated with chimpanzees are male-dominated (Goodall, 1971), with male alliances often mediated by aggression toward males and females. In bonobo social structures, male dominance is present, though displays of this dominance generally occur among males and with less aggression than is characteristic of chimpanzees (de Waal, 1995). Thus, violent displays of dominance in bonobos are of a lesser degree and severity than in chimpanzees, with bonobo competition for male ranking occurring between males and being influenced by the rank of the competing male's mother. Though bonobos are female-centered in their social structure, male dominance still exists, but to a lesser degree.

Bonobos are omnivorous secondary consumers (Lambert, 2012), feeding on a variety of species from various trophic levels, including ants, earthworms, termites, and some vertebrates such as small rodents (Bermejo, Illera & Zaire, 1994). In addition, the diets of bonobos are rich in plants and their associated fruits and seeds. This diverse food web can also consist of mushrooms (Bermejo, Illera & Zaire, 1994). Thus, bonobos derive energy from a diverse food web, consuming producers, and primary consumers. With few predators, bonobos can be found near the top of their ecosystem's food chain, though below tertiary consumers, such as leopards (D'Amour, Hohmann & Fruth, 2005). Opportunistic feeding habits allow bonobos to eat other mammals (White, 1996), such as squirrels, though they are not active predatory hunters (Bermejo, Illera & Zaire, 1994). Bonobos also have been observed practicing the washing of herbaceous plant material before consumption (Bermejo, Illera & Zaire, 1994) and have been recorded feeding on honey, by carefully probing the nests of Trigona spp. (a genus of stingless bees), before consuming its contents (Bermejo, Illera & Zaire, 1994).

Diurnal by nature, bonobo feeding activity begins immediately upon morning waking from arboreal nests (Fruth & Hogmann, 2010), and as addressed in the beginning paragraph, sharing between group members is not uncommon. This is likely due to the relationship between sex and food (see biology), something that has been observed in both captive and wild bonobo populations (d Waal, 1995). This characteristic is thought by some, to be a response to competition, something that would typically arouse aggression in other primate species, but in bonobos seems to stimulate sexual behavior that may function to diffuse tension (d Waal, 1995). Though this hypothesis is speculative and warrants further investigation, it speaks to the complicated role of sexual interaction in bonobo life, something that will be discussed in brief on the Biology section of this website.

According to information provided by the San Diego Zoo (N.D.), morning feeding is then followed by a period of rest before ground travel to other food sources. Along the way, the bonobos will casually feed on vegetation, and by mid-day, activity begins to retard, yielding to an afternoon of further feeding and travel. By nightfall, arboreal nests are built in near proximity to the most recent feeding site (Serckx et al., 2014). According to the San Diego Zoo (N.D.), these nests can are found at heights of up to 49'. The following morning, this cycle continues. According to the San Diego Zoo (N.D.), an approximate breakdown of this daily cycle equates to 43% of the day spent resting, 18% arboreal feeding, 20% terrestrial travel and feeding, and 13% traveling. something that can range between 1.5-15 km/day.

Having briefly explored the social and ecological relationship between bonobos and their environment, one can conclude that bonobos have a diverse diet that is primarily insect and plant based, with feeding behavior analogous to snacking occurring on the go, as troops travel from one food source to another. This lifestyle and fruit-based diet plays a crucial role in identifying the niche of these primates.

Primates are thought by some scholars to have coevolved with angiosperms, an event that would have occurred early in the evolutionary history of primates, when the divergence from a rudimentary common ancestor of euprimates, bats and other phylogenetically linked mammals occurred (Sussman, 1991) (see evolution). This hypothetical branch point might represent the emergence of adaptations in relation to improved ability to exploit the nutritional value of food items such as flowers, fruit, and seeds (Sussman, 1999). If this hypothesis is accurate, then it suggests a coevolutionary relationship that is directly linked to the known ecological service of seed dispersal, via bonobos, as a result of dietary habits.

Bonobos have been observed, in one study, to consume over 133 different plant species, of which 91 seed-bearing specimens were observed to have been eaten by the bonobos examined in the study (Beaune et al., 2013). Examination of the associated fecal matter showed that over 98% of the scat clusters contained seeds, of which contributed to an average 67% of the fecal weight (Beaune et al., 2013). As shown in the study conducted by Beaune et al. (2013), over 95% of the seeds remained viable after defecation and had a higher germination frequency than unpassed seeds. Other results found in this publication support the ability of these seeds to be transported over distances of up to 100 m. In addition, 67% of the scat piles examined produced seedlings (Beaune et al., 2013). This data indicates that mutualism between various plant species and bonobos is robust. Thus, one can conclude that frequent travel in search of food (that often contains seeds), aids in the proliferation of plant life via seed dispersal. This relationship between bonobos and plants may owe its existence to macroevolutionary changes that cooccurred in early anthophytes and the common ancestor of rudimentary primates (see evolution).