Since then, the attitude towards animals has changed but feelings and emotions have always been so difficult to study that for many years scientists didn’t even try to decipher them. But now, thanks to recent advances in neuroscience, we have the means to understand what is happening inside animal brains. We have discovered that, like us, they feel emotions such as fear, anger, sadness and love. And they need these emotions in order to survive. From primary to more complex emotions, this documentary explores the internal lives of a whole range of species in the animal kingdom.