http://www.livescience.com/animals/070514_femchimp_killers.html
http://www.msnbc.msn.com/id/7087194/
http://www.newscientist.com/article/dn11844-stressed-female-chimps-kill-rivals-young.html
With such exaustive research by j_b, and selection of sources, you can definitely discard anything he posts or quotes on any topic.