Keeping classroom animals is a common practice in many classrooms. Their value for learning is often seen narrowly as the potential to involve children in learning biological science. They also provide opportunities for increased empathy, as well as socio-emotional development. Realization of their potential for enhancing primary children's learning can be affected by many factors. This paper focuses on teachers' perceptions of classroom animals, drawing on accounts and reflections provided by 19 participants located in an Australian primary school where each classroom kept an animal. This study aims to progress the conversation about classroom animals, the learning opportunities that they afford, and the issues they present. Phenomenographic analysis of data resulted in five categories of teachers' perceptions of the affordances and constraints of keeping classroom animals.