Stumbling around this morning waiting for a student to show up online (he never did), I came across this:

Now, I had never heard this – but my stepdaughter happens to be insane about hippos, so I thought this might make a cute shirt for her. A bit of searching, however, raised a problem: despite countless hits and re-posts and re-blogs, and entries in things like Yahoo Answers (otherwise known as the blind leading the blind, but don’t get me started), it seems that it’s just not true.

It turns out that hippos produce a natural sunscreen. From Wikipedia: “Their skin secretes a natural sunscreen substance which is red-colored. The secretion is sometimes referred to as “blood sweat,” but is neither blood nor sweat. This secretion is initially colorless and turns red-orange within minutes, eventually becoming brown. Two distinct pigments have been identified in the secretions, one red (hipposudoric acid) and one orange (norhipposudoric acid). The two pigments are highly acidic compounds. Both pigments inhibit the growth of disease-causing bacteria; as well, the light absorption of both pigments peaks in the ultraviolet range, creating a sunscreen effect. All hippos, even those with different diets, secrete the pigments, so it does not appear that food is the source of the pigments. Instead, the animals may synthesize the pigments from precursors such as the amino acid tyrosine.”

Like all mammals, hippos produce white milk; when the milk mixes with these skin secretions, it may acquire a pink color cast. At ASPCA kids, one of the answer-writers produced this with regard to the question:

“You’re right about hippos oozing an awesome red-pink liquid to keep away bugs and germs and avoid sunburn, Finley! But pink milk? Sounds too crazy to be true. But you’re also right that many websites claim hippo babies are drinking pink milk.

I’m sorry to say that I don’t know any hippos personally, so to answer your question I had to turn to the experts—specifically, Dr. Rebecca Lewison, an ecologist and hippo conservationist at San Diego State University. According to Dr. Lewison, the pink milk thing is totally false! She thinks people are confusing hippos’ pink secretion with their milk. I guess you can’t believe everything you read on the Internet—except when at ASPCA Kids, of course.”

I’ll take the word of the experts on this one. Hippo milk is white.

The Old Wolf has spoken.