In prairie dog colonies, an individual will give an alarm call if it sees a predator approaching. This animal’s behavior benefits neighbors by warning them, while causing risk to itself by drawing the attention of the predator. This is an example of altruism. It is difficult to see how altruistic behavior could evolve since the altruistic act lowers an individual’s fitness. However, when examples of altruism are examined carefully, the individuals that benefit are found to be close relatives of the altruist. In prairie dog colonies, for example, neighbors are part of an extended family. This means that those individuals that benefit from the altruism share many of the altruist’s genes, including those responsible for altruism. So the genes for altruism increase although some individual altruists die.