<p>To advance an integrative understanding of human nature, we advocate for a bold shift in focus across behavioral science towards the study of suicide and its avoidance. Suicide is not just another symptom or social issue among many; it profoundly influences human affairs. It is a major cause of death around the world and can leave psychological scars on the bereaved. Its pervasive impact is reflected in the world’s literary and artistic heritage. Yet suicide remains marginalized in science education, overlooked by major theoretical frameworks, and under-researched relative to the scale of mortality caused. The unrecognized scientific importance of suicide is, at root, evolutionary: human vulnerability to suicide—a harmful by-product of sapience—exerted a powerful selective pressure in our deep ancestral past. A suite of psychological and cultural defenses evolved to mitigate the danger, protective machinery that we have inherited. It displays in diverse human traits of the kind that behavioral scientists from varied fields are drawn to study: puzzling, species-typical psychological biases and behavioral patterns that are conspicuously costly but bring unclear benefits. Manifestations may include optimism bias, spirituality, arts and sports, prosocial morality, self-serving self-deception, psychoanalytic defenses, diverse psychopathological symptoms, and even human consciousness. With the shared substrate currently obscured by taboo, these phenomena are usually studied in isolation, perpetuating a fragmented understanding of human nature. The reconceptualizing of <i>Homo sapiens</i> as a suicide-avoidance specialist points to a new, long-awaited Kuhnian paradigm in behavioral science, one that is directly linked to promoting well-being and saving lives.</p>