[Taxacom] Potential human orangutan evidence

Ken Kinman kinman at hotmail.com
Tue Nov 19 20:29:53 CST 2013

Hi John,                   
       A very interesting paper on orangutan behavior.  However, I seriously doubt its phylogenetic potential for great ape phylogeny.  Why would chimps or particularly gorillas have any need to "broadcast" their plans for the next day?  A dominant male gorilla might be thinking about what direction to take the next day (or next few hours), but why would he need to broadcast it with loud calls?  When the time comes, he just moves in that direction and his females follow him. Gorillas or chimps moving in groups are a whole different dynamic than a relatively lone orangutan male who needs to communicate over longer distances.                                   
      I also doubt that any human male "broadcasting" would be synapomorphic with such orangutan broadcasting.  It sounds more like convergence (or parallelism at best).  Or if gorillas and chimps do clade together (exclusively), it could be a plesiomorphy for great apes which was lost in gorillas and chimps because they didn't need it---in which case one might want to seriously look for such broadcasting in male gibbons, which could indicate a possible plesiomorphy for all the apes (lesser and greater). This seems more likely than a synapomorphy between humans and orangutans.  

> Date: Tue, 19 Nov 2013 10:53:26 -0500
> From: calabar.john at gmail.com
> To: taxacom at mailman.nhm.ku.edu
> Subject: [Taxacom] Potential human orangutan evidence
> Carel van Schaik et al (2013) published a paper that may have interesting
> phylogenetic implications. It is a behavioral study that shows how male
> orangutans make a call to other orangutans in the vicinity that lets them
> (males and females) know where that amle orangutan intends to move about
> the next day. This broadcast approach to communication with respect to
> intentions the next day has not yet been demonstrated in other great apes,
> but of course it is an ability expressed in humans. Other great apes (and
> some other animals) certainly can plan ahead, but this type of broad
> casting as well as for an event that is not of the same day is so far only
> known in humans and orangutans. More comparative research obviously needed.
> Article is open acces: van Schaik CP, Damerius L, Isler K (2013) Wild
> Orangutan Males Plan and Communicate Their Travel Direction One Day in
> Advance. PLoS ONE 8(9):e74896. doi:10.1371/journal.pone.0074896
> Excerpt
> Captive experiments have previously suggested the presence of
> the ability to plan for the future in great apes, but cannot reveal in
> which natural context this ability is used, if at all. The present
> study strongly suggests that wild Sumatran orangutans at Suaq
> Balimbing use this ability in the range-use context. Thus, the last
> long call given shortly before the flanged male went to sleep for the
> night provided a better than random prediction of his travel
> direction during the next day until 16:00 hrs, hence approximately
> 22 hours after the call was given. These findings therefore indicate
> that flanged male Sumatran orangutans make their travel plans at
> least a day in advance and announce them through their
> spontaneous long calls. The ranging responses of his audience
> show that other orangutans actually use this information,
> suggesting in addition some communication of plans from the
> male to his female audience. The delay in responses by the
> audience on the next day to long calls heard the evening before is
> also consistent with the presence of episodic memory in the
> listeners.
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