The third in the series of Evolution-Health animations (created at FableVision for the New York Hall of Science) is on Lactose Intolerance, and probably the trickiest to explain. While a lot of us can digest milk well into adulthood, some of us cannot. Basically, we're all born with the enzyme to digest the lactose in our mother's milk when we are infants, but until tens of thousands of years ago, there was no reason to retain that ability once our mothers weened us. It wasn't until some cultures began raising livestock that animal milk became a valuable source of nutrition—people who could drink the milk were at a new advantage (thus, more apt to survive and reproduce). Those who couldn't, well—didn't do so hot with cow's milk.
I actually named these kids in the Flash file as I was drawing them. From left to right: Sam, Amelia, Danielle, Jason, Nikki, and Lily.
Nikki is not pleased.
Parts of Europe, Africa, and East Asia didn't partake in the whole animal milk thing and are now more likely to have difficulty with lactose.
But, it ends on a happy note. The kids who can't drink the milk help themselves to some orange juice. (Yes, that's an orange juice mustache.) I can't take full credit for this gag—Margie Prager from Jeff Kennedy Associates wrote in the orange juice bit. I did add the pulp flecks.
Next up: Sunburn.