Out of the 6 mammal species that engage in rape, 5 are primates. Only 3 of those 6 do it routinely: Elephant seals, orangutans, and people. Every animal species organizes its society based on sex in some way. Chimpanzees, most genetically similar to use, also show the most similarity to humans in their organization and behavior. Males form into groups and individuals struggle for dominance to gain access to females. In any species, when males compete for females, the males tend to get bigger than females. They routinely batter their females. (From lecture 2: "A study of ten countries ranging from Japan to Ethiopia showed that in most sites between 30% and 56% of ever partnered women, had experienced both physical and sexual violence." Probably an underreporting.) I've heard it said that humans are the only species that engages in warfare, but that not true. Unfortunately, it's only our closest relative that does it: Chimpanzee groups form into Us vs Them categories and try to wipe each other out. In Lecture 2 there's a brief but striking description of the night before a chimpanzee raid. Normally they hoot at each other before going to sleep to sort of say "good night" to each other, but one night they were all completely silent. Turns out they were being silent to sneak up on another group. I'm surprised that they were able to communicate and coordinate the decision to attack like that. I like to put the audio of these courses on my MP3 player and listen while I'm driving. So far I've listened to: HIST 119 - The Civil War and Reconstruction Era, 1845-1877, Spring 2008 HIST 202 - European Civilization, 1648-1945, Fall 2008 PHIL 176 - Death, Spring 2007 PLSC 114 - Introduction to Political Philosophy, Fall 2006 PSYC 110 - Introduction to Psychology, Spring 2007 PSYC 123 - The Psychology, Biology and Politics of Food, Fall 2008 RLST 152 - Introduction to New Testament History and Literature, Spring 2009 MCDB 150 - Global Problems of Population Growth, Spring 2009 Again, out of those, the one in the OP is my personal favorite.
Yale Online Courses has an awesome course called Global Problems in Population Growth. (According to the current issue of National Geographic, sometime this year global population will hit 7 billion. Didn't we just pass 6 billion a while ago?) The Yale Online Courses are free. Global Problems of Population Growth is by far the best of the courses I've listened to. It's appropriate to MoFi because it illustrates some of the similarities among primates.