The objective of the research was to find, using also a theory of domains, such stereotypical characteristics of animals that had become a basis for signs created in the first European boarding schools for the Deaf. These signs are of iconic nature, motivated either by the animal's appearance (visualizing one or more of its characteristic features, such as ears, whiskers of a beak) or by a typical behavioral pattern of the animal itself, incl. its movement, or a human interaction with it (calling a dog, horse riding).