“Cats Are (almost) Liquid!—Cats Selectively Rely on Body Size Awareness When Negotiating Short Openings”, Péter Pongrácz2024-09-17 (; backlinks; similar)⁠:

Various animal species can make a priori 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 (n = 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 whether cats would rely on their body awareness in other challenging spatial tasks.

…Recently we tested dogs in various settings, where they had to make shortcuts through apertures that were comfortably large, or too small for them to fit through easily. We found that dogs, depending on the relationship between their own body height (at the withers) and the size of the opening, opted for approach without hesitation (“suitable size opening”), or arrived at the opening with longer latencies (“too small opening”). If the opportunity was given to them, dogs opted for a detour in the case of uncomfortably small apertures. Dogs belong to a group of fast moving, pursuit-type predators, where collisions, or getting stuck within too narrow openings, would have serious consequences—therefore in their case, a well-working, body size awareness-based avoidance system, is of high relevance…But what about cats? Similar to dogs, most cats share a complex and changing environment with humans,33 and companion cats also engage in various social activities with their owners34,35. In addition to the aforementioned ecological enablers, by taking in consideration the well-developed socio-cognitive capacities of cats,36 one could hypothesize that these animals will likely show evidence of size-awareness. However, cats are ambush predators that mostly move slow and careful, and they often use elevated vantage points.37 Their anatomy is highly specialized for climbing, jumping, and even for avoiding the fatal consequences of falling from considerable heights.38 As they do not have functional collarbones, they show remarkable adaptation for squeezing through narrow gaps.39

Therefore, we hypothesized that cats would behave differently than dogs when they encounter such apertures that are seemingly too small for them (Figure 1 & Figure 2). We predicted that instead of hesitating while they approach the opening, cats will try entering the gap, and only decide to go through or not, when they experience its actual size (Figure 3). In other words, we expected that cats will not capitalize their body awareness in such tasks (going through a hole), which in their case, can be solved via other, biologically relevant ways.

Figure 2: Two variants of the incrementally decreasing size openings.

…Based on this, we provided evidence that cats probably did not make detectable a priori own size-based decisions when they approach narrow but comfortably tall openings, even if these were narrower, than the chest width of the cat. At the same time, when the openings became shorter than the cats’ height at the withers, they hesitated approaching them, and even tried to find alternative solutions to negotiate the panel. Remarkably, taller cats opted for this solution more often than the shorter subjects. This indicates that for cats, the vertical and horizontal dimensions of an aperture represent different importance. The passable, but uncomfortably short openings elicited noticeable hesitation in their approaching, thus indicates a reliance on body size representation in the cat.

…such precautions would probably be superfluous for a cat, because of their specific features of locomotion, anatomy and space usage. Cats prefer environments with a complex structure (plenty of hiding places, vantage points, in other words: “obstacles”), where they usually move slowly and with great agility.41 More importantly, their anatomy supports flexibility42 and their free-floating, diminutive collarbones43 allow them to squeeze themselves through very narrow gaps. We assume that this was the main reason why did cats readily approach the very narrow openings without apparent hesitation: for those narrow but tall openings represent no relevant trouble to negotiate, thus (probably aided by experience, i.e. body awareness) for them the uninterrupted approach was the biologically meaningful solution.

…Cats are also aided by their large and sensitive vibrissae, which are positioned on such locations of their head that the cat can detect nearby obstacles in closer encounters. Vibrissal sensation can compensate for the somewhat weaker vision in cats from closer distances or in poorly illuminated environments.44, 45 Therefore, it is possible that cats approached the narrow openings in our experiment without differential hesitation, and they could use their vibrissae to assess the suitability of the apertures before penetrating them.

All in all, for cats, the adaptive response to a narrow opening would most probably be to approach it without hesitation. The next step is to actively try it, to see whether they can actually get through.