Wet food contains 75–82% moisture vs 8–12% in dry kibble. Per calorie, wet food is typically higher-protein, lower-carb, more palatable, and supports hydration — particularly important for cats, who have weak thirst drives. Trade-offs: 3–5x more expensive per calorie than dry, requires refrigeration after opening, and slightly worse for dental tartar. Many owners feed a mix of dry and wet rather than choosing one exclusively.