They all have Black Hair

I finally drew a picture of Arrin. I'll post it in a couple days.
I'm tempted to give my characters really different hair, including color, length, curliness, and style. Since I'm not great at drawing distinct facial features, the hair helps me give them more unique designs.

But my last two stories have been set in their world's equivalent of North America. In my worlds, the American Indians (their equivalent, anyway) weren't crushed when Europeans came (spreading disease, killing the buffalo, forcing them into reservations, all that stuff). They are still very much there. Some live in cities or towns. Many still live in their lodges or travel along with the buffalo.
I don't know the percentage, but most of the people living in their North America are the original people. There are plenty of people from other countries, because there's lots of migration in those worlds (it's fast and easy to travel, and it's easy to start living in another country). But still, most of them should be the original people.
Which means it would not reflect my world if my main characters all had really different hair colors. Because the local people all have black hair.
So a large majority of my characters have black hair too.

Well, my next zoo photo has black hair too.
The goofy teenage gorilla.