The article explores the path followed, since ancient times, to enhance the legal protection of animals. After the description of the evolution of the concept of animal from the ancient Greeks to present day, the work describes how the concept of animal protection has evolved and has become a constitutional value. The Author then focuses on the German system of animal protection, to underline the main concept of the con- stitutional animal protection since Germany is one of the leading States in the world in the affirmation of this constitutional value. The evolution of the concept of animal protection is analyzed with a legal comparison between Italy and Germany because the Italian constitutional reform that introduces the value of animal protection in the Italian Constitution occurred 20 years after the German one.