The symptoms of fear have always been the same.

They were the same when men had to face wild beasts and they are the same today.

Blood drains away from the face and epidermis, to avoid blood loss. It's why people turn pale.

The intestines relax and release everything, so there will be no toxic matter left to contaminate the organism. It's why people "shit themselves".

The body initially refuses to move, so as not to provoke the predator by any sudden movement. It's why people freeze up.