stressful situation would be the start of the release of epinephrine (adrenaline),
cortisol, and other stress mediators in a cat’s body.
These have many effects. In the short-term, they produce increased body
temperature, increased alertness and activity, increased heart rate, eye
(pupil) dilation, piloerection (hair stands on end), sometimes
elimination, hissing, spitting, biting, and scratching behaviors (or
running and hiding!).