Animals, IMO are very well equipted to quickly & pretty accurately. Size-up a potential food source or danger, & strength/weakness.
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Our 100lb. male German Shephard constantly is sizing me up daily. If I show any slight sign of weakness, he'll cue right in. Hmmmm, it's opportunity-time, WRONG.
He's 10yrs old now. Some years back, I went to take him by the collar. He lunged for my throat. Needless to say, a battle was not far away. Later that day, he was lying on the LR floor on his L-side(we still were angry with each other).
I slowly slid up by him, petting him. Talking softly, making little eye-contact. Once I got my R-hand near his muzzle. I "quickly" clamped his muzzle shut. Grabbed his throat with my Left hand & flopped my body on top of him( I weigh, 220lbs) pinned him good. At this point he wanted BLOOD! I looked him right in his R-eye & bit his R-ear hard, while not blinking...eye-eye. After a 15-20 min cool off period(he needed it, not me LOL!). I slowly slid off. No more attacks after that.