“He was shortish. And oldish.
And brownish. And mossy.
And he spoke with a voice
that was sharpish and bossy.”

That’s how Theodor Geisel describes his character the Lorax. (You probably know Mr. Geisel by another name—Dr. Seuss.) And now researchers think they know what the real Lorax was: a monkey!

When he wrote the book The Lorax, Dr. Seuss was visiting the African country of Kenya. He had already written many books kids and grownups loved. But he had writer’s block—he couldn’t think of what to write next. Researchers at Dartmouth College say he probably got his new idea by watching the patas monkey in Kenya. Like the Lorax, the patas monkey has orange fur and stands on two feet.

Do you remember the Lorax’s story? The Lorax warns a character called the Once-ler not to harvest too many fluffy Truffula trees. But the Once-ler is greedy. He chops down almost all the trees for his own gain. As they disappear, so do the creatures living nearby. The Brown Bar-ba-loots have no Truffula fruit to eat. The Swomee-Swans’ throats fill with factory smoke. The Humming-Fish get gummed-up gills when factory gunk spills in their water. Finally, even the Lorax himself has to leave.

For years, professor of anthropology Nathaniel Dominy had thought patas monkeys looked like something Dr. Seuss would create. But he didn't start researching his theory until he started reading The Lorax to his children. After that, he and another professor used a computer to study the Lorax’s face. Their research showed the Lorax looks more like a patas monkey than other Dr. Seuss characters do.