Within the evolutionary life history (LH) framework, aggression and risk‐taking are adaptive implementations of a fast LH strategy to adapt to environmental unsafety and unpredictability. Based on a longitudinal sample of 198 Chinese adolescents liv‐ing in rural areas, half of whom were separated from their parents, this study tested LH hypotheses about aggression and risk‐taking in relation to safety constraints in the childhood living environments. The results showed that proxies of environmental unpredictability, including parental separation, were positively associated with ag‐gression and risk‐taking and negatively associated with slow LH strategy, which in turn was negatively associated with aggression and risk‐taking. Children separated from their parents scored lower on slow LH strategies and higher on aggression and risk‐taking. These findings support the evolutionary assumption that human develop‐ment responds to safety cues through behavioral implementations of LH strategies.