Why does the head hair go grey but other body hair does not?

Head hair tends to go grey due to a decrease in melanin production as we age, which is influenced by genetics and the aging process. The hair follicles on the scalp are more sensitive to these changes compared to body hair, which may retain its color longer. Additionally, other factors such as stress, hormonal changes, and environmental influences can affect hair pigmentation differently across various parts of the body. However, it's important to note that body hair can also turn grey, but it often occurs at a different rate or age than head hair.