Ask a grown-up: why aren't there many green animals?
That's a very good question, considering so much of the natural world is green and camouflage so important in it, but I'm afraid there is no simple answer. Many animals are green, for instance snakes, frogs, lots of insects and some birds, but many mammals are not, because they have found other ways to protect themselves from predators. For example, many are nocturnal or live underground in burrows in the dark, so colour isn't a necessity for camouflage. Other larger animals, such as zebras, prefer to live in the long grass, where it is far better to have a pattern that will break up the animals' body shape, and to be equipped to be very agile under threat of attack.
Many mammals do not differentiate colours – in other words, they are colour-blind – so it wouldn't matter if they were green or brown. And as humans, we see colour differently from animals, so what we perceive to be good camouflage actually may not be to them.
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