Language is a unique property of humans. It is located in our brains and is intimately connected with our experience of consciousness. Our interaction with other humans via language is the main means by which we can be sure that others experience levels of consciousness like ourselves. However, many animals have communication systems which in principle are similar to language, that is, they are used to convey information between members of a species, though not always by means of sounds. For instance, bees use a special set of movements in which information about a source of nectar, its size and distance from the hive, is transmitted by movements in space by the bees, their ‘dance’. Whales use noises sent out beneath the water to other whales. Other senses can and have been used for communication. For example, many insects exude pheromones, scents with a certain signal value for a member of a species, normally to attract females.