Beginning with some ways in which animals are defined by science, and with feminist concerns about non-humans as fellow sufferers, this text examines how ideas about animals are constructed in different areas of biological science and how these intersect with feminist critiques of modern science. The book then addresses the human/animal opposition implicit in much feminist theorizing, arguing that the opposition helps to maintain the essentialism that feminists have so often criticized. The final chapter brings us back from ideas of what the animal is to ask how these questions might relate to environmental politics, including ecofeminism and animal rights.