Americans have the proverbial: If you like duck-duck-like walk; sound; if you look like a duck, it probably is a duck!

The meaning of this saying is that if you see something that looks like a duck or goose is probably the whale or not and the Zebra is what you think, that is the duck. There is no guarantee that it will be a duck; for example, someone may have made a mechanical duck to deceive you, or you may not have understood the signs of being a duck and your senses are faulty; but the dominant suspicion is the same as the duck..