Like monkeys picking fleas, she giggled.

Why are you picking fleas in my trousers?

All of them naked, like monkeys in a zoo picking fleas.

Similarly, monkeys pick fleas from other monkeys which benefits both because its like a treat.

I go up to the attic, where Peter is busy picking fleas from the cat.

He looked down to Weedle and Malinger, who had landed by his booted feet and now were picking fleas off each other.

A man picking fleas.

It enables us to live in big groups and is, in a suitably apt analogy, the human equivalent of apes picking fleas off each other.

Terry ignored him, hoping the two neanderthals would go away and sit in a tree somewhere, eating leaves and picking fleas from each other.

Moon Pie had come in, and Sam held him under the light and picked fleas off his head.