A look at partnerships forged by unrelated species. For instance, lions and lizards: the big cats enjoy uninterrupted naps thanks to the reptiles, which feast on flies buzzing their partners; and, in return, lions generally don't snack on the lizards. Also: the working relationships between the goby (a small warm-water fish) and the shrimp; tarantulas and toads; and hippos and barbells (a little fish). Also: creatures that band together, such as elephants, wolves and ants.