Many preschoolers know that plants and animals share basic biological properties, but this knowledge does not usually lead them to conclude that plants, like animals, are living things. To resolve this seeming paradox, we hypothesized that preschoolers largely base their judgments of life status on a biological property, capacity for teleological action, but that few preschoolers realize that plants possess this capacity. To test the hypothesis, we taught 5-year-olds one of four biological facts and examined the children's subsequent categorization of life status for numerous animals, plants, and artifacts. As predicted, a large majority of 5-year-olds who learned that both plants and animals, but not artifacts, move in goal-directed ways inferred that both plants and animals, but not artifacts, are alive. These children were considerably more likely to draw this inference than peers who learned that the same plants and animals grow or need water and almost as likely to do so as children who were explicitly told that animals and plants are living things and that artifacts are not. Results also indicated that not all biological properties are extended from familiar animals to plants; some biological properties are first attributed to plants and then extended to animals.