Over the last two decades, substantial changes in the morphological paradigm of the images used in environmental signage, especially in public recreation areas, have shown a freedom of formal solutions. Where there used to be a perfect and unequivocal pictogram, today there are images influenced by tendencies and/or context. Some zoos use differentiated systems of signage. Sometimes the use of pictographic images prevails; other times, more relevance is given to photographs.The Rio de Janeiro Zoo was chosen for a semiotic study of signing objects, in particular the visual identification of the animals in their cages, their possible interpretations and their consequences.