The cool temperatures of the Quaternary may have allowed our brains to become much larger than those of our of hominid ancestors. (newscientist.com)
Our small hominid ancestors probably faced the same kinds of threats that baboons do today from leopards, eagles, and other predators. (discovermagazine.com)
Thus, it may well be that our early hominid ancestors toted their babies around, too, rather than letting them crawl. (scientificamerican.com)