Altruism, an act that bestows a benefit on the recipient while conferring a cost to the actor, is one of the central paradoxes of evolution. In the wild, where only the fittest survive, adopting other animals' offspring is not really in line with Darwin's theory of evolution. And yet, amongst bees, dolphins, lions and several primate species, altruism may go as far as adoption. In the case of social insects, parent substitution was a flaw in Darwin's theory of evolution by natural selection: the biologist noticed that non-reproductive insects who adopted and helped young ones, brought a large portion of genetic baggage from their parents. Darwin had to broaden his theory to the family group. For mammals, including men, what advantage is there in the act of adoption? In the years following the adoption, does the adopted individual contribute to the foster parents' survival and vice versa? The controversy at the heart of this documentary continues to be debated in today's scientific world. While raising these different questions, this documentary will study each case separately because each adoption behaviour has evolved independently forming its own pattern, its own benefit and even... its own disadvantages.

How strong is the similarity between animals and humans? At first glance, we do not have so much in common. But forget the pressures of religion, culture and society. Make abstraction of what we have always believed and see the truth in the eye. Man is by no means an outsider in the evolution of the species. Five years filming brought the truth to light: the animals did it first! This series examines the similarities between humans and animals in the area of ​​Emotions, Language, Medicine, Homosexuality, Adoption, Tools, Trade, Play Mode, Culture and Politics.