Article by By Janelle Nanos on March 3, 2010 National Geographic Blog He looked like a single black king moving across a chessboard of so many white pawns. Our first glimpse was puzzling until we drew closer and realized that this was not some other bird but indeed another penguin of a different color. Our group from Lindblad Expeditions spotted this very unique bird at Fortuna Bay on the subantarctic island of South Georgia. Out of several thousand pairs of king penguins, this was the only individual that was entirely black although earlier in the morning I had spotted another that showed muted coloration. Recent science papers (PDF) show that the trait has been documented only a handful of times in South Georgia. Some fellow travelers recall seeing a melanistic penguin at St. Andrew's Bay, also on South Georgia. Melanism is merely the dark pigmentation of skin, fur--or in this case, feathers. The unique trait derives from increased melanin in the body. Genes may play a role, but so might other factors. While melanism is common in many different animal species (e.g. Washington, D.C. is famous for its melanistic squirrels), the trait is extremely rare in penguins. All-black penguins are so rare there is practically no research on the subject--biologists guess that perhaps one in every quarter million of penguins shows evidence of at least partial melanism, whereas the penguin we saw appears to be almost entirely (if not entirely) melanistic. So far, king penguins represent the most documented cases of melanism, though there is evidence of partial melanism appearing in other penguin species, namely Adélie, chinstrap, gentoo, macaroni and royal penguins. Observing this black penguin waddle across South Georgia's black sand beach revealed no different behavior than that of his fellow penguins. In fact, he seemed to mix well. Regarding feeding and mating behavior there is no real way to tell, but I do know that we were all fascinated by his presence and wished him the best for the coming winter season.