Survival of the fittest means that those individuals of a species with genetic traits that are best adapted to the particular environment are most likely to mate and pass those traits on to the next generation. Importantly, survival of the fittest does not mean that the most aggressive and dominant will pass their genes on to the next generation. Dominance is one evolutionary strategy, but it is not the only one. For example, in some fish species, male fish can disguise themselves as females and then sneak into the dominant male’s territory to mate with his females. In this case, fish that are not the most dominant nevertheless reproduce successfully. Moreover, in many circumstances, cooperation and altruism can be useful evolutionary strategies—as effective, if not more effective, than competition and aggression.