Cats have excellent night vision, and can see well at one-sixth of the light level required for humans. They also have excellent hearing and can hear higher-pitched sounds than both dogs and humans. The cat’s hearing is amongst the best of the mammals.
In addition to these great senses, cats have an acute sense of smell. It might not be as good as a blood-hound, but it’s still twice as good as a human’s.
When cats meet they don’t usually greet each other nose to nose, because that puts both participants in a vulnerable position. Cats who know each other well and have been apart for a while feel safe enough to do this, and through the nose contact they gather information about how the other cat is, where they have been, and what they have been doing.
Most human societies find it polite to meet another’s gaze. Cats do the opposite; they blink and narrow their eyes when they accidentally make eye contact. To make friends with an unfamiliar cat, try to blink and look away when you catch his eyes.