The hippo version of sweat is red-orange, and Japanese researchers have now isolated two pigments responsible for the colorful glow.
Tests so far confirm years of speculation that this skin secretion can block microbial growth as well as some ultraviolet light, says Kimiko Hashimoto of Kyoto Pharmaceutical University. The pigments are highly acidic compounds containing carbon rings, Hashimoto, Yoko Saikawa of Keio University in Yokohama, and their colleagues report in the May 27 Nature.
The researchers named the newly identified red pigment hipposudoric acid and the orange one norhipposudoric acid. If chemists could make more-stable derivatives, Hashimoto says, "these pigments would be seeds of pharmaceutically important compounds."