The red fluid that is secreted through hippopotamus skin and commonly called “blood sweat” is neither blood nor strictly sweat. The scientific name for the pigment is hipposudoric acid and in our latest episode, Hippopotomology (HIPPOS), conservation ecologist and hippo researcher Dr. Rebecca Lewison explains: “A fantastic group of scientists from Japan in 2004 was able to extract some [blood sweat] and figure out molecularly what’s going on. That secretion both protects them from the sun and seems to be an important antibiotic.” Despite having one of the thickest skins in the animal kingdom — up to 2.5” (6cm) thick — hippos are vulnerable to sunburn. They’re just like us! Except hippos produce a natural sunscreen that blocks UV rays and inhibits the growth of bacteria. In a video from @zookeeperguy, a close-up on a hippo reveals beads of an oily red substance dripping from its pores. The fluid is actually colorless at first, then gradually turns red. Listen to Hippopotomology (HIPPOS) at the link in bio and follow @zookeeperguy for so many more great hippo videos.