Humans have the same number of hair follicles as chimpanzees.
While human hair traits have been on the books for decades, in 2018 Kamberov and Harvard collaborators published the first systematic comparison with other primates (aside from a 1931 study that did not include vellus hairs). Analyzing skin biopsies from cadavers under a microscope, the team counted hair follicles in five body regions (forehead, back, chest, forearm and thigh) of seven humans, four chimpanzees and eight rhesus macaque monkeys. Although the sample size was small, the results showed that chimps and humans have about the same density of hair follicles. However, what sprouts from those follicles differs. Over most body regions, chimps have thick fur, whereas humans have fine vellus hair. Some are so small, they can only be seen with a microscope.
Going furless was not merely a means to an end; it had profound consequences for subsequent phases of human evolution. The loss of most of our body hair and the gain of the ability to dissipate excess body heat through eccrine sweating helped to make possible the dramatic enlargement of our most temperature-sensitive organ, the brain.