What are the ways animals communicate?

When we think of communication, we normally think of using words—talking face-to-face, writing messages and so on. But in fact we communicate far more in other ways. Our eyes and facial expressions usually tell the truth even when our words do not.
     Then there are gestures, often unconscious: raising the eyebrows, rubbing the nose, shrugging the shoulders, tapping the fingers, nodding and shaking the head. There is also the even more subtle "body language" of posture: are you sitting or standing with arras or legs crossed? Is that person standing with hands in pockets, held in front of the body or hidden behind? Even the way we dress and the colors we wear communicate things to others.
     So, do animals communicate? Not in words, although a parrot might he trained to repeat words and phrases which it doesn’t understand. But as we have learnt, there is more to communicate than words. Take dogs for example. They bare their teeth to warn, wag their tails to welcome and stand firm, with hair erect, to challenge. These signals are surely the canine equivalent of the human body language of facial expression, gesture and posture.