Stephen Colbert gave one Penn State professor her daily dose of "truthiness" last night.

Nina Jablonski, the head of Penn State's anthropology department, appeared on Comedy Central's The Colbert Report to promote her book, Skin: A Natural History, published in 2006 by the University of California Press. Colbert, who was more concerned with the effects of exfoliation and the anomaly of Steve Carell's thick fur coat, provided comic relief to Jablonski's science lesson on the epidermis.

"I don't see skin color," he said. "I move beyond race. I don't even see skin -- I move down to the ligaments and the joints. I judge those."

Jablonski explained that, unlike most books which focus on skin, her book examines the evolution of hair and skin color, which diversified as humans migrated from tropical areas. One of Colbert's complaints concerning the book was the lack of "naked ladies."

"All there was was a naked Neanderthal lady," he said before displaying an human ancestor with a comically blurred-out nipple.

"I just sold you a few books," he said.

Jablonski handled Colbert's witticisms poorly at first, until she warmed to his off-topic jabs.

When Colbert asked, "Is it possible that I'm blacker than Barack Obama," she smoothly transitioned back on topic.

For highlights: comedycentral.com