Cats can be considered a type of "liquid" in a scientific sense, but only under certain conditions and time scales. According to physicist Marc-Antoine Fardin, who won the 2017 Ig Nobel Prize in Physics, cats exhibit properties of both solids and liquids depending on observation time. Over short timescales (such as when a cat lands on its feet), they behave like solids, but over longer timescales (such as settling into a container), they flow and conform to shapes like a liquid. This duality is explained using rheology concepts and the Deborah number, which measures how materials relax and flow.

Additionally, research shows that cats have a degree of body size awareness and can adapt their body shape fluidly to fit through progressively smaller openings, demonstrating liquid-like behavior in their movements.

In summary, cats are not liquids in the everyday sense but behave like liquids in some physical and biological ways, particularly when fitting into containers or moving through narrow spaces. This behavior is observed over specific time scales and depends on the geometry of their environment.