Mixed Breed isn't a breed but a label for any dog with ancestry from two or more breeds, or with ancestry no one knows. That covers everything from compact terrier-type dogs under 20 pounds to shepherd, hound or retriever mixes over 70. Coats, colors, ears and builds can come from any branch of the family tree, so no two look quite alike.
Because ancestry varies, the most reliable guide is the dog itself: its size, energy, age and how it reacts to people and other animals. Research suggests breed explains only a small share of behavior, so choosing on personality rather than looks tends to work well. Expect moderate shedding, a lifespan of roughly 10 to 15 years, and care needs that scale with size and coat.