From special glands in their skin, hippos form a reddish oily fluid, which is sometimes called ‘blood sweat’. But the fluid is not in fact sweat. While, in humans and other mammals, sweat evaporates and acts as a fluid to cool down the body, in hippos it is an antibiotic, water repellent, sunscreen and skin moisturiser, all in one. Besides, it comes in pink, how cool is that!