Felidae is the family of cats. Its subfamilies are Pantherinae, which includes apex predatory megafauna such as tiger, lion, jaguar, leopard, and others, and Felinae, including all the non-pantherine cats, like the small, furry, domestic cat (猫 neko). Cats are obligate carnivores; they must consume meat to survive. Therefore, they are sometimes referred to as hypercarnivores because of the much higher proportion of protein they require in their diet, much more than most other mammals.
Cats with the same appearance as the ones from Mega Man Zero 3 appear in Area C as part of the background.
Kattelox Island has several black cats. After defeating the Marlwolf, Mega Man Volnutt can go to the Main Gate's entrance and take one of the three cats roaming in the area to the Flutter. The amount of cats inside the Flutter increase as time passes, reaching up to 8 cats of varying size in the Living Room and 3 in Mega Man's Room. Mega Man is able to understand what some of them say. Also, later in the game one cat will appear in the Yass Plains and two in the Cardon Forest. Mega Man is able to kick cats in the Japanese version of the game, but his armor will become darker if he kicks them repeatedly.
- In Mega Man Legends 2, Mega Man mentions that Kattelox Island had several cats when he sees the cat plaque in Kimotoma City.