Most series either stick to a specific age group, or start out with an age group and grow with that generation. This series decided to do the opposite and devolve, and is abysmally unfaithful to the first movie. The series started in a mostly realistic ice-age world. Animals mostly behave like normal animals, they don't use tools, they don't wear clothes, species normally keep to themselves, they get hunted by humans, etc. We somehow go from that, to an absurd world where animals replace humans. Animals do strange human things, including futuristic things that didn't exist in that era, and the existence of humans are never referenced.