New series. Mongoose start wars to create a diversion for sneaky mating, while macaques kidnap babies to curry favour with their rivals. These behaviours prompt Liz Bonnin to investigate the animals who will stop at nothing to find a mate and raise a family. Liz reveals the fascinating science that lies behind some extraordinary tactics. In Tanzania, she finds out that sibling rivalry can actually benefit a whole hyena clan, and on the North American plains learns how promiscuity can be the key to having healthy prairie-dog pups. However, the presenter also discovers that such tactics are often the key to survival.