Ferrets (Mustela furo) Are Aware of Their Dimensions

SIMPLE SUMMARY: Self-awareness is defined as the ability of an individual to perceive one’s physical and mental properties separately from the characteristics of the external world and/or other individuals. Traditionally, self-awareness is considered as one of the attributes of human consciousness, indicating the meaningfulness of human behavior. In recent years, there has been increasing evidence of self-awareness in different animal species. One of the earliest evolutionary components of self-awareness is body size awareness, which is expressed in the ability to consider the boundaries of one’s own body when interacting with environmental objects. In this study, we examined body size awareness in ferrets. During the experiments, the animals had to pass through holes, some of which were too small for their bodies to penetrate, and some were suitable. The results show that ferrets could pre-select the penetrable opening, even when the impassable ones were larger. We believe that these data indicate the presence of body size awareness traits in ferrets, which in turn suggests their self-awareness. This opens the way for the study and discussion of self-awareness in many other animals. ABSTRACT: Self-awareness is a complex phenomenon expressed as the ability of an individual to separate “self-entity” from “other entity”. One of its earliest evolutionary components is body size awareness, namely, the ability to consider the boundaries of one’s own body as factors influencing interaction with surrounding objects. For ferrets, Mustela furo, the task requiring the penetration of various holes is ecologically relevant. We designed an experimental study in which the ferrets were supposed to select one opening out of three to get the bait. The first experiment was aimed at studying whether ferrets would prefer the holes basing on the hole size. In the second experiment, we tested the ferrets’ ability to select a single passable hole on the first try while the impassable ones were larger in area. Results from the first experiment show that when choosing from the three passable openings, the animals preferred the shortest path to the bait and ignored the size of the holes. In the second experiment, all tested ferrets preferred to penetrate the passable opening on the first attempt, even though the areas of the two impenetrable ones were larger. We argue that these data indicate that ferrets are aware of their own body size.