UV | Ask Dr. Universe | Washington State University

Why are giraffes’ tongues purple? — Winona, 6, Wisconsin

February 5, 2026 melissamayer

Dear Winona,

When I was a kitten, I visited a drive through zoo. A giraffe slithered its long, purple tongue through the open car window and licked my face.

It was awesome.

It turns out dark colors come from a pigment called melanin. That melanin makes a giraffe’s tongue purple, blue or black.

I asked my friend Cynthia Cooper about melanin. She studies pigments—the colorful stuff in animal cells—at Washington State University.

She told me melanin is also why human skin gets darker from being in the sun.

A giraffe stands tall and stretches its neck to grab foliage ... <a href= » More …

September 19, 2024 melissamayer

Dear Seth,

Since I’m a fluffy cat, my fur protects me from the sun. But my hairless cat and human friends use sunscreen when they go outside.

I asked my friend Michael Smerdon how it works. He’s a biochemist at Washington State University.

He told me that the sun puts out different kinds of light. Some light is visible to humans. Some is invisible—like UV light.