Every spring, my nose and forehead begin to get freckles. By mid-summer, my face is filled with them. What are freckles, anyway?
Signed, Dear Jane

Dear Jane:

The answer is a simple one. Melanin. Melanin, you know, is the chemical pigment that gives us all our skin color. No matter what the shade of your skin (or hair, for that matter) -- white, yellow, tan, olive, brown, or black, -- the color comes from varying amounts of melanin produced by cells in your skin.

When you are exposed to the sun, those cells begin to produce extra melanin. That's how you tan. (And, regardless, of skin color, everyone's skin is affected by the sun!) It's also what causes freckles. Sometimes the tanning isn't uniform and some of the cells containing melanin seem to be especially energetic. They work overtime. That causes some tiny patches of skin to darken from melanin, while others don't. Voila. You've got Freckles!

Oh, and Jane, to my mind, freckles make you humans look even more adorable!

Signed,

Wendell