Different species of animals can be territorial and shun anyone that looks different from their inner circle and dogs can be of that type. Some dogs are bred to specifically dislike people of certain races and other dogs simply develop a distrust of certain people on their own. But does this make them racist? I’ve worked with dogs whose owners have warned me about their dogs and people of color and it made me wonder how they got that way? After doing some research it appears that dogs develop their strongest opinions on people and their “world” between the ages of 3 weeks through 12. So if they are not exposed to certain people during this stage or worse if they have a bad experience with a certain type of person, it can have a lifelong effect on the dog. Of course there is the unfortunate situations where a dog is specifically trained to dislike or even attack a person of a different race. But at the end of the day the consensus appears to be that no, dogs are not racist and they simply fear (as humans do) what they are not familiar with. A dog might also be afraid of a man in uniform, or a man with a beard and so on. If you have a puppy try and expose them to a wide array of people and stimulus and if you think your dog has issues with skin tone or any issues with physical features you should consult an animal behaviorist.