Royals look very much like Macaroni Penguins, but have a white face and chin instead of the Macaronis' black visage. They are 65–76 cm (26–30 in) long and weigh 3–8 kg (6.6–18 lb). Males are larger than females. They are not to be confused with the similarly named King Penguin or Emperor Penguin. There is some controversy over whether Royal Penguins are a sub-species of Macaroni Penguins. Individuals of the two groups have been known to interbreed, though this is a relatively rare occurrence. Indeed, other penguins have been known to form mixed-species pairs in the wild.