Update: meat eating gorillas???

The new paper "Vertebrate DNA in Fecal Samples from Bonobos and Gorillas: Evidence for Meat Consumption or Artefact?" by Hofreiter et al. (2010) started getting a lot of press today, see here, here and here (and a very nice addendum to this last post here)

First of all, its really interesting that the main point of the paper, which was to test whether or not prey DNA could be amplified from BONOBO feaces was possible, was omitted or barely reported on, in any of the media outlets.

Even more interesting is how eagerly journalists have been to jump on this new discovery even though the authors admit (in the title even!) that it may be an artefact. In fact, one blogger even goes on to attack Grit Schubert (who is an excellent scientist, woman and an author on the very paper that put the meat eating gorilla hypothesis forth) for suggesting that gorillas do not eat meat and accusing her of being a scientist all too ready to cover up "the facts". There is over 20 years of consistent, behavioural data from field researchers from multiple sites across the western gorilla range who have been painstakingly following gorillas EVERY DAY and have never observed them to consume meat. Relying on some inconclusive genetic results over mountains of behavioural data is not biased, it's rational.

I think Linda Vigilant puts it best in her PLosOne comment:
Did we learn anything from this study?

It is interesting that a study can be published in a peer-reviewed journal even though the title admits that the results may all be artefacts. It would not be hard to do a controlled study on this topic. There are groups of well-habituated chimpanzees where one could collect fecal samples after they have been observed to consume meat, and conversely there are well-studied wild gorillas that have never been observed to consume vertebrate prey. And to control for contamination of the fecal samples in the field, once could try amplifications from soil samples. Then it might be possible to actually say whether molecular analysis of primate diets using feces is useful or not, and perhaps even produce some believable results.

Full disclosure, Linda Vigilant and Grit Schubert are colleagues of mine at the MPI-EVA - MA