Understanding how children think about the needs of animals may aid bridging from how they care about individual animals to caring about the environment more generally. This study explored changes with age in children's conceptions of animals' needs, including how such conceptions may extend beyond the individual animal to larger systems and conservation. During attendance at a North American zoo, 171 children between the ages of 4 and 14 years were interviewed and did drawings in response to questions about the needs of a favorite animal. The results reported here focus on developmental patterns. Animals' basic physiological needs were grasped at an early age. Understanding ecological and conservation needs showed the strongest developmental trends across the full age range, with some children showing early proficiency in ecological, but not conservation, concepts. Conservation and ecological thinking appeared to follow different trajectories, especially through middle childhood, when other dimensions than knowledge may cause increases in conservation conceptions. Educational implications include building on interest in individual animals; not underestimating even young children's ability to assemble ecological facts around an animal; emphasizing concrete ecological connections; and highlighting animals that children experience in their own lives. Considering the needs of animals offers a developmentally pre-potent way to increase how children know and value multiple levels of biological organization.