Unselfishness - not just humans anymore

Chimpanzees will often lend a helping hand even if there's no reward, suggests research published this week, challenging theories that altruism is unique to humans.

While helping behaviour isn't uncommon among non-human primates, it's usually attributed to family relationships or selfish benefits, researchers at Germany's Max Planck Institute for Evolutionary Anthropology noted.

But in this study, "they clearly seemed to be motivated by the other person's unachieved goal and not an immediate benefit for themselves," author Felix Warneken told CBC News.