Martin Stevens explores the extraordinary variety of senses in the animal kingdom, and discusses the cutting-edge science that is shedding light on these secret worlds. Our senses of vision, smell, taste, hearing, and touch are essential for us to respond to threats, communicate and interact with the world around us. This is true for all animals - their sensory systems are key to survival, and without them animals would be completely helpless. However, the sensory systems of other animals work very differently from ours. For example, many animals from spiders to birds can detect and respond to ultraviolet light, to which we are blind. Other animals, including many insects, rodents, and bats can hear high-frequency ultrasonic sounds well beyond our own hearing range. Many other species have sensory systems that we lack completely, such as the magnetic sense of birds, turtles, and other animals, or the electric sense of many fish. These differences in sensory ability have a major bearing on the ways that animals behave and live in different environments, and also affect their evolution and ecology. In this book, Martin Stevens explores the remarkable sensory systems that exist in nature, and what they are used for. Discussing how different animal senses work, he also considers how they evolve, how they are shaped by the environment in which an animal lives, and the pioneering science that has uncovered how animals use their senses. Throughout, he celebrates the remarkable diversity of life, and shows how the study of sensory systems has shed light on some of the most important issues in animal behaviour, physiology, and evolution. He also describes evidence of the disruptive effects of human activities on the way other animals navigate the world.