Here's a breakdown of why:
* Melanin and Hair Structure: Melanin is the pigment that gives hair its color. Darker hair has more melanin. Melanin also contributes to the density and thickness of the hair shaft. Because dark-haired people have a higher concentration of melanin, their individual strands are often thicker.
* Hair Density: While individual strands might be thicker in dark hair, blondes sometimes have a *higher number* of hairs on their head (higher density). This can give the *illusion* of thicker hair overall.
* Genetics and Other Factors: Hair thickness is influenced by genetics, health, diet, and other factors. There are always exceptions to the general rule.
In summary:
* Dark hair: Usually thicker individual strands
* Blonde hair: Sometimes higher density (more hairs overall), but often finer strands
It is important to note that this is a general trend, and individual experiences can vary.