Among more than 5,000 kinds of mammals, only human bodies are significantly hairless and very different from other animals. Imagine, if you shaved your pet dog or cat (or even thought about a polar bear), how would they look? How would they feel to the touch? Scientists have provided three important explanations regarding why humans do not have fur. All these explanations revolve around this idea: despite humans sharing a common ancestor with our closest living relatives, chimpanzees, 6 million years ago, having less body hair has been beneficial for our lineage's evolution.