Callicebus nigrifrons

How genes for altruism can benefit strangers as well as kin The generosity of adoption has long been considered a unique human hallmark. Image: Shadows of Forgotten Ancestors For decades it was conventional dogma that humans were the only species that used tools. "Man the Toolmaker" was our celebrated designation. The hominin fossil Homo habilis (or "handy" man) was even defined within our genera primarily because the skeleton was associated with stone implements. However, when Jane Goodall discovered chimpanzees using modified sticks at Gombe to "fish" for termites, Louis Leakey famously…