Why do dogs characteristics differ so much more than other spieces?

If you look at the difference between a chiuhaha and a great Dane, you can spot a ton of characteristics that are different from eachother. Why do dogs have so MANY different characteristics (tails, fur, noses, ears, etc.) and other animals dont? Like if you look at humans, we might have different skin tones and heights, but we don't differentiate as much as dogs do. Basically, we have the same kind of ears (dogs can have droopy, short, pointy), the same kind of skin (some dogs are bald some dogs have wirey hair, some are poofy some are shaggy) and dogs have more variety of colors in their hair (while we have brown black blonde and red..)