Humans have roughly the same number of hair follicles as chimpanzees.

Anthropologists and biologists, including researchers like Nina Jablonski, have determined that humans and chimpanzees both possess approximately 5 million hair follicles across their bodies. The primary difference lies in the type of hair produced. Humans have a high density of vellus hair, which is light and translucent, whereas chimpanzees are covered in terminal hair, which is thick, pigmented, and provides significant insulation.This evolutionary divergence likely occurred around 2 to 3 million years ago as early hominids moved from shaded forests to open savannas. During this period, species like Homo erectus began engaging in high-activity behaviors such as persistence hunting. To prevent the brain and body from overheating in the direct sun, the human body prioritized heat dissipation through the skin.The loss of thick fur allowed for a more efficient eccrine sweat gland system. Humans have between 2 million and 5 million eccrine glands, which is a much higher density than that found in other primates. This combination of 'naked' skin and high sweat production allows humans to cool down via evaporation more effectively than almost any other mammal.Genetic studies suggest that the KRTHAP1 gene, which helps produce keratin for terminal hair, became a pseudogene in humans hundreds of thousands of years ago. This genetic 'deactivation' is one reason why our body hair remains fine and short. Despite appearing hairless, a human's forehead has roughly the same number of follicles as a chimpanzee's, proving that we didn't lose our hair, we just changed its texture.