Uexkull compares an animal’s body to a house, with windows—the senses—that open to the world. In his example, the world is represented by a garden. The first 11 chapters provide an understanding of different senses and how they open up different worlds for different animals. But, of course, Uexkull is interested not only in the windows themselves but also in how they are integrated into the architecture of the house. This requires an understanding of how the windows work on their own, as well as how they might “open” and “close” in coordination with one another. Chapter 12 focuses on this coordination of the senses, and it also pays attention to how animals coordinate sensory information coming from outside their bodies with information coming from within their bodies.

Every animal relies on more than one sense, and animals use as many senses as their nervous systems can manage. Sense organs provide two forms of information whenever animals move: exafference and reafference. Exafference refers to stimuli from the outside world, while reafference indicates signals produced within an animal. Yong describes the former as “other-produced” and the latter as “self-produced.