Rheology is the branch of physics that studies the deformation and flow of matter, and under its strict definitions, domestic cats perfectly fit the criteria of both a solid and a liquid depending on the circumstances.

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Rheology is the branch of physics that studies the deformation and flow of matter, and under its strict definitions, domestic cats perfectly fit the criteria of both a solid and a liquid depending on the circumstances. Because felines lack a rigid collarbone and possess incredibly flexible spines, they can actively conform to the exact shape of whatever container they are placed in, from glass bowls to cardboard boxes, just like a fluid. Physicists have actually published serious research papers analyzing the relaxation time of a cat settling into a sink, proving that academia occasionally tackles the truly important issues facing humanity. So when your furry roommate inexplicably slithers under a door gap that is barely two inches wide, just remember that you are housing an amorphous, non-Newtonian fluid with claws and a serious attitude problem