Brian Stewart’s research exploring the adaptive uniqueness of Homo sapiens has featured in the April 2019 issue of Discover Magazine. In a piece titled ‘The World is Our Niche’, contributor Bridget Alex highlights Stewart and co-author Patrick Roberts’ new theory of Homo sapiens as adaptive ‘generalist-specialists’. In a 2018 article that appeared in Nature Human Behaviour, Stewart and Roberts make the case that our species' behavioral evolution can best be understood by charting our extraordinary ecological plasticity instead of searching for the elusive origins of symbolism, language, social networking, technological complexity or enhanced cognitive function. They critically reviewed the growing archaeological and environmental datasets relating to the dispersal of our species within and beyond Africa. They argue, based on comparison with the available information for other members of the genus Homo, that Homo sapiens developed a new ecological niche. Not only did we occupy and utilize a diversity of environments, but we also specialized in our adaptation to some of these environmental extremes. As Alex writes in the Discover piece, "Most animals stick to particular habitats, related to where they fall on a continuum between generalist and specialist. Creatures like raccoons are textbook generalists, which inhabit varied environments and consume diverse food. Specialists, such as koalas, have a limited range and diet. Stewart says Homo sapiens may ‘uniquely have the ability to tack back and forth … along that continuum,’ allowing them to live just about anywhere. ‘I haven't seen any cases of other animals that can do that,' Stewart says. You won’t find Arctic species in the Sahara, or mountain creatures in marshland – except for Homo sapiens.” Stewart and Roberts stress in their Nature article that our species' extraordinary ecological tolerance is underwritten by a capacity for complex, rapidly transmittable and limitlessly mutable culture. Understanding this ecological niche provides a framework for discussing what it means to be human and how our species became the last surviving hominin on the planet.
* 5/17/19 - This article is available to online subscribers only. It should become open access soon.*