Flamingos seem to be born grey. The colour gets more vibrant as they feed on certain algae and crustaceans (shrimp, primarily) that thrive in these salty, alkaline waters. In a way, the intensity of their pink colouring tends to be a reflection of their health (and that of their habitat).
Wow! You actually get these in Texas, Florida, and Louisiana?
You led me to read this about the platypus: "The unusual appearance of this egg-laying, duck-billed, beaver-tailed, otter-footed mammal at first baffled European naturalists. In 1799, the first scientists to examine a preserved platypus body judged it a fake, made of several animals sewn together."