Rough Humor on Instagram: "This video demonstrates a common cat behavioral response to a concentrated auditory stimulus. The Subject The subject is a domestic black cat in a state of rest. It exhibits a sudden shift from a relaxed posture to an acute startle response when a high-decibel vocalization is directed toward it. The Mechanism The reaction is triggered by the feline’s highly sensitive hearing. The sudden increase in sound pressure activates the "startle reflex," causing rapid muscle con