It’s a combination of two distinct pigments: one red (hipposudoric acid) and one orange (norhipposudoric acid). These pigments absorb ultraviolet light, preventing damaging rays from penetrating the hippo’s skin. Moreover, this secretion is both antibacterial and antifungal, providing an all-...
The observer thus sees the highest intensity looking at the rays that have minimum deviation, which form a cone with the vertex in the observer’s eye and with the axis passing through the Sun. Light emerging from raindrops after one internal reflection has a minimum deviation of about 138° ...