Dogs are domesticated mammals that have been selectively bred by humans for thousands of years. They are known for their loyalty, companionship, and wide range of breeds with different characteristics. Dogs have a keen sense of smell and hearing, making them excellent hunters, guard animals, and companions. They require regular exercise, grooming, and proper nutrition to thrive. Dogs come in various sizes, colors, and coat types, making them one of the most diverse species of animals on Earth.