Bonobo primates have better developed neural pathways related to empathy

[warwick]

Bonobos have better developed neural pathways related to empathy than human beings.

" Bonobos also have a larger pathway linking the amygdala with the ventral anterior cingulate cortex, a pathway implicated in both top–down control of aggressive impulses as well as bottom–up biases against harming others."

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3324566/

"Chimpanzees exhibit more severe aggression than bonobos. Within social groups, chimpanzee aggression involves male aggression against females, male infanticide and intense male competition for dominance status. In contrast, male aggression against females is rare in bonobos"

[warwick]

From an interview:

http://www.pbs.org/wgbh/nova/evolution/learning-bonobos.html

"SUSAN K. LEWIS: So you don't see anger in bonobos?

VANESSA WOODS: You see anger, but not the murderous rage that you get in chimpanzees and humans. I mean, when we become lethally angry, we are gonna kill someone. Like just the other day, someone was murdered in this town that I live near. And I just wake up and I know that that's something that might happen to me.
When a chimpanzee wakes up in the morning, they know the same thing. There's a possibility that another chimpanzee will kill them. And bonobos, they just don't have that. "

Bonobos:
"there is no possibility that they are going to be killed by one of their own species. And I think that, for all our intelligence, this is something that we haven't been able to do, and we keep making the same mistakes over and over again.

[warwick]

"Those two apes develop differently, Hare said, and they respond to social stress differently. Chimpanzee males experience a strong rise in testosterone during puberty, but bonobos do not. When stressed, the bonobos don't produce more testosterone, as chimps do, but they do produce more cortisol, the stress hormone."

http://www.sciencedaily.com/releases/2014/08/140801171114.htm

[Pappy]

http://www.bbc.com/earth/story/20160317-do-bonobos-really-spend-all-their-time-having-sex

Seems the excess sex hormones are cause of the rage. ;)

http://news.nationalgeographic.com/news/2008/10/081013-bonobos-attack-missions.html