http://www.sciencedaily.com/releases/2007/12/071206100557.htm

The findings could help biologists sort out altruism's evolutionary history, according to the scientists. They noted that a version of AVPR1a also exists in rodents called voles, where it also promotes social bonding. This suggests that altruism has a long rooted genetic history, which may have taken on a new role during human evolution.
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"Beneath an ever watchful eye...the angels of the temple fly"