Ce que vit le rhinocéros lorsqu'il regarda de l'autre côté de la clôture - Cie 15 000 cm² de peau

A Siberian bear, the new attraction at this strange zoo, gradually discovers that a fence separates two groups of men, that the previous bear, who has gone mad, tried to escape but failed, and that the zoo's rhinoceros died some time ago.
What has driven the bear mad?
What could the rhino have seen to make him die of sadness despite his thick skin?
And why does this gigantic chimney burn day and night, even in spring?