"great ape" sex (was: Stuffing the ballot box)

John Grehan jgrehan at SCIENCEBUFF.ORG
Tue Jan 11 15:47:12 CST 2005

> John,
>       Since three (out of five) of your newest characters deal with

Please keep in minds that they are only being treated as possibilities
at this time.

> started thinking about the bonobos.  Female bonobos are not dominated
> males the way regular chimps tend to be and are known to initiate sex
> and/or foreplay with males.  

I'm not so sure about either being correct. Could you give citations? I
read a couple of De Waal's books and there is no reference to either the
initiation of copulation or foreplay(the only thing referred to is
females presenting themselves to males (which might be thought of as
initiating sex), but it is the male who initiates the actual copulation.
I'm not asserting that initiation of copulation or foreplay by females
with males does not occur in bonobos but I am not aware of cited
examples at this time. I look forward to the citations Ken as it would
be helpful to resolve this comparison (and if limited to humans,
bonobos, and orangutans it would provide for quite a different monophyly
argument - although that would be outweighed by the orangutan-human
level of character support).

And bonobos often have sex face-to-face (the
> female genital orientation is said to be a bit more like humans).  

It's actually not that often when it comes to male-female copulation as
the total is 30% or less. I haven't been able to get figures for
orangutans, but apparently face-to-face applies to the great majority of

I've seen the claim for genital orientation, but it is just claimed - no
comparative morphological information on bonobos and other primates at
this time.

And now
> that I think about it, bonobos often have a pretty good head of hair
> humans)---probably longer than orangutan head-hair.

Someone might check on that, but in one way there is a difference in
that orangutan hair is flexed forward as it is usually that case for
humans, while in chimps and bonobos the hair is flexed either back or to
the sides (and humans and orangutans have a receded hairline unlike
chimps or bonobos).

>       Perhaps you should compare humans with bonobos, rather than with
> regular chimps.  

People certainly have tried, but the problem of a lack of synapomorphies
still applies.

Perhaps even better to compare bonobos with
> australopithecines.  

Also been tried in the literature, but australopiths have thick dental
enamel, and orangutan-human-like shoulder blade, and skulls like

I think I am going to be looking at the following
> possible cladistic  topology:
>   Orangutan (hominid (bonobo (reg. chimp (gorilla)))).

If you can make a morphological case for it I will be very interested to
see it. I'm not sure how much any one else has tried to put chimps and
gorilla as sister groups (which certainly conflicts with the genetic
similarity - and I though Ken supported that evidence). As for leaving
orangutans out from hominids, that's appears to be possible by leaving
out the orangutan-human synapomorphies. At present my response would be
that this arrangement is without foundation. So put up the evidence Ken!

>       Here is a link to a picture of some bonobos with a nice head of
> hair.  Their browridges even look like they might be a bit "mounded"

They are not in the way they are in orangutans in that bonobos (and
chimps and gorillas) have a posterior sulcus and the brow ridge extends
between the eyes (orangutans and australopiths do not for both

John Grehan

>     http://www.unm.edu/~astro1/ET109/whatislife/bonobo.jpg
>        ------Ken Kinman

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