What is the difference between dog fur and dog hair, and how can you distinguish between the two?

Dog fur and dog hair are often used interchangeably, but there is a difference between the two. Dog fur refers to the soft, fine undercoat that helps insulate the dog, while dog hair is the coarser, outer layer that provides protection. You can distinguish between the two by feeling the texture - fur is softer and finer, while hair is coarser and thicker.