The uncommon chimpanzee (revised 4/20/09)
photo by JL at SD zoo.
[Comments or questions by me (jl) are prefaced usually by (jl) or followed by (?)]
Be sure to read the links and readings by deWaal for general background.
Filmed at the San Diego Wild Animal Park, Escondido
The role of neoteny - (See Shea in EHE, p.104)?
Bonobos greater similarity to us also be due to their relatively neoteny, i.e.. they are paedomorphic relative to common chimps with all that entails--including more human-like features. This might entail some more human-like behaviors, e.g. face to face intercourse that in turn may have implications for social relationships, etc. Neoteny thus is a source of changes, variations, that natural selection may draw upon.
(jl) how much of this is a neotenous development relative to common chimps?
They travel for food, 15 kilos day, 80% time feeding --not different from other apes. Bonobos are omnivorous but eat vegetation primarily with some insects and small mammals. I haven't heard any reports of systematic hunting like the common chimps sometimes engage in. See Wrangham's paper in TO.
gestation about 8 months
nurse till 4; dependent till 7 years
females leave their natal group
integrated into new group when a female becomes a mother
males stay with group and maintain a very close relation with mom
highly social and cognizant of rank
minimal within-group male competition as well as minimal cooperation compared with common chimps
Less within-group violent aggression than common chimps
Dominant males become more interested around ovulation - (JL change in color
of swelling and/or olfactory cues?)
g-g rubbing, masturbation, oral sex
prolonged estral swelling
JL - These sexual encounters are really quick; do they have orgasms comparable to humans? If they were human, the entire species would probably be in jail for these activities in public -- not to mention activities with juveniles!!
(jl) no wonder they "talk" about them!
JL comments and notes:
It is widely reported that female bonobos dominate male bonobos. While this is often true, I don't think it is true in all situations. Here is a paragraph from a recent study (note that most of these studies are in captive populations):
"For the moment the term nonexclusive female dominance (Vervaecke et al. 2000a) seems to apply best to the patterns of dominance in the 6 captive groups and has serious implications for interspecific comparisons. Nonexclusive female dominance in bonobos is different from complete female dominance in other species, such as spotted hyenas (Crocuta crocuta; Drea and Frank 2003) and lemurs (Lemur catta; Kappeler 1990; Propithecus diadema; Pochron et al. 2003; and Hapalemur griseus; Waeber and Hemelrijk 2003). However, female dominance among bonobos, even if nonexclusive, remains a striking contrast with chimpanzee society, wherein males generally dominate all females in the group (Goodall 1986). "
International Journal of Primatology
The Official Journal of the International Primatological Society
© Springer Science+Business Media, LLC 2007
Sex Differences in the Steepness of Dominance Hierarchies in Captive Bonobo Groups
Jeroen M. G. Stevens1, 2 Contact Information, Hilde Vervaecke4, Han de Vries3 and Linda van Elsacker2
or see this report from Wamba; Takeshi Furuichi (2004) International Journal of Primatology, 18,
Agonistic Interactions and Matrifocal Dominance Rank of Wild Bonobos (Pan paniscus) at Wamba
" Dominance between males and females is unclear, but females tended to have priority of access to food. The close social status between males and females may be related to the prolonged estrus of females and their close aggregation during ranging. Existence of a male''s mother in the group and her dominance status among females seemed to influence his dominance rank among males. "
Conjecture that bonobos are a good model for humans must deal with dissimilarites including bonobo promiscuous sex not openly seen in any human culture as far as I know, and the much greater degree of dependence of human moms on social support including that of the father.. In bonobo society, as in c chimps, fathers are unknown to anyone but the DNA investigators.
See the PBS Nova notes on the recent Bonobo video. --'Last great ape'