Parent-child conversations are a potential source of children's developing understanding of the biological domain. We investigated patterns in parent-child conversations that may inform children about biological domain boundaries. At a marine science center exhibit, we compared parent-child talk about typical sea animals with faces (fish) with talk about atypical sea animals without faces (e.g., sea stars), in particular with respect to anthropomorphic talk and use of animate pronouns. Parents talked about psychological states and used animate pronouns more often for typical than atypical animals; children showed a similar pattern for pronouns but did not differ in their property talk between typical and atypical animals. It was clearly parents who initiated the use of psychological properties and animate pronouns for typical animals. These patterns suggest that parent-child conversations draw boundaries between typical and atypical animals and could support children's inclination to anthropomorphize.