Cats are (almost) liquid!-Cats selectively rely on body size awareness when negotiating short openings.

Various animal species can make decisions about the passability of openings, based on their own size knowledge. So far no one has tested the ability for self-representation in cats. We hypothesized that cats may rely on their size awareness when they have to negotiate small openings. Companion cats ( = 30) were tested with incrementally decreasing sized openings, which were either the same height, or the same width. Cats approached and entered even the narrowest openings, but they slowed down before reaching, and while passing through the shortest ones. Because of their specific anatomical features and cautious locomotory strategy, cats readily opt for the trial-and-error method to negotiate narrow apertures, but they seemingly rely on their body-size representing capacity in the case of uncomfortably short openings. Ecologically valid methodologies can provide answers in the future as to whether cats would rely on their body awareness in other challenging spatial tasks.