We present data illustrating how preschool-aged British children ranked the danger of different situations and adults rated various external causes of mortality. Ranks were calculated from 34 children’s ratings of dangers presented by eight scenarios using a three-dimensional diorama. Lion and hippopotamus figurines were presented to characterize historical threats with intentional agency. Children ranked the lion followed by the hippopotamus as presenting the greatest danger. When these ranks were pooled to reflect a general category of animal attacks, the children’s ranks failed to reflect the national statistics on childhood deaths. Adult ratings for the prevalence of 20 external causes of mortality in the general public were positively correlated with the actual frequency of mortality due to these causes. Nevertheless, adults were seen to underestimate their personal susceptibility to the same dangers. Children and adults differ in risk assessment based initially on early childhood predispositions, with experience altering risk assessment to match the local environment.