What photos have you taken of animals that are showing some attitude or emotion of some sort?

A captive lion sidling up to a lioness seductively. The female was uneasy and backed away, rejecting his advances. The atmosphere was tense and I imagine that she was feeling rather uncomfortable.

A strong male chimpanzee giving me a stony glare.

A litter of feeding piglets being scattered by their formidable father, who was intent on having his share of the feed.

 A wild American bison bellowing to establish his dominance.