Cats and dogs can coexist peacefully in multi-species households, but the welfare of both species depends critically on how introductions are managed and how the household environment accommodates their different needs.
Unsuccessful multi-species introductions cause chronic stress for both species, particularly cats who are more easily trapped and cannot escape. A cat living in constant fear of a dog shows welfare indicators including hiding, reduced social interaction, stress-related illness, and inappropriate elimination. Dogs that constantly pursue cats are frustrated by the cat's refusal to engage appropriately. The welfare solution requires environmental management: safe refuges for cats, physical barriers where needed, separate feeding stations, and systematic behavioral introduction. When fundamental incompatibility exists (high-prey-drive dogs), welfare may require the decision not to maintain the mixed household.