In this exploration of human social behavior, renowned field biologist Dr. Marc van Roosmalen draws from decades of primate research to illuminate the deep evolutionary roots of modern tribalism. Through a masterful blend of scientific insight and compelling narrative, he reveals how our ancient territorial instincts continue to shape today's social challenges, from discrimination to racial anxiety. Van Roosmalen introduces revolutionary concepts like "survival of the fittest group" and "social selection," offering fresh perspectives on why humans naturally form exclusive groups and often view outsiders with suspicion. Drawing from his extensive experience in the Amazon rainforest and his deep understanding of primate behavior, the author weaves together fascinating observations, evolutionary theory, and contemporary social issues to explain the biological foundations of human tribal behavior. "Civilisation has ever accompanied emigration and conquest - the conflict of opinion, of religion, or of race." ALFRED RUSSEL WALLACE (1823-1913).