These animals are also great at nonverbal communication. Once, we were working a group of lionesses loose in an arena. I was elected to give out the supply of meat and work the buzzers behind the protection of an electric hot wire. One of the electrical connections had slipped off the connector during our training. With a male lion I probably would have been in grave jeopardy despite having taken the precautions before we started.
Male lions are another story.
They can switch moods immediately. From a nice big lion enjoying a breeze to a wild beast that will kill you over a blade of grass. When they grump around they remind me of a big bully with a scowl on his face. In fact, I do not encourage it. Too many animals are not cared for properly by people who think it would be fun to own one.