Animals can be good, for example, at working co-operatively. Oxen, hogs and other creatures will gather in groups for self-defence. If a parrotfish23 is hooked by a fisherman, his fellow parrotfish rush to chew through the line and free him. Or, if one is netted, others thrust their tails through the net so he can grab one with his teeth, and be pulled out. Even different species can work together in this way, as with the pilot fish that guides the whale, or the bird that picks the crocodile’s teeth.
