Hi Michael,
I just registered to see the photo, and indeed the photographer got the moment the blackback was doing a chest beat display. Nice photo! It is VERY hard to get facial shots with some light to bring out the features of a black face. Each gorilla has a distinct 'noseprint', which is a bit hard to see on this photo. This blackback was mostly bluffing I suspect, and trying out his 'stuff'. That's the job of young males (in our species too).
Thanks for the link. I wonder if the photographer would like to post some of her shots on Primate Field School website (starts this summer).
http://studyabroad.arizona.edu/datab...m.aspx?id=1805
or
www.wild-minds.org