Cats can share a litter box, but it is generally not recommended for most situations due to their territorial nature and individual preferences. While some cats may tolerate sharing a box without issues, many prefer to have their own litter box space. Sharing can lead to stress, territorial disputes, aggression, and behavioral problems such as avoiding the box or inappropriate elimination. The widely accepted guideline for multi-cat households is to provide one litter box per cat plus one extra to ensure cleanliness, reduce conflict, and promote a harmonious environment. This "N plus one" rule helps prevent problems related to litter box sharing, including hygiene concerns and dominance behaviors. In summary, although cats can share a litter box, it is best to have multiple litter boxes in a household with more than one cat, ideally one per cat plus an extra, placed in different locations to accommodate each cat's needs and preferences.