A White Penguin
David Stephens at National Geographic snapped this picture of a rare white penguin on the Aitcho Islands. This Chinstrap Penguin (Pygoscelis antarcticus) is not albino, it is leucistic. Albino animals lack pigment, typically because of a flaw in an enzyme involved in producing melanin. You may remember learning a little about penguin melanin in the fossil penguin Inkayacu. Leucistic animals are able to form melanin, but generally have a mix of cells that produce melanin and cells that cannot. This results in a “washed out” appearance in cases like the penguin below. Whatever triggered the condition (typically a gene mutation is involved), the penguin ended up with light brownish coloration on its back instead of the black coloration of normal Chinstrap Penguins. Notice, though, that the beak and part of the feet are still black. Leucism often affects a particular area of a bird rather than the entire individual. White penguins turn up in the wild every year. However, it appears that either the mutations associated with leucism are recessive or the condition harms the penguins by ruining their counter-shading camouflage, because second generations have never been documented.