Leucism:
Leucism (/ˈljuːkɪzəm/;[1] or /ˈluːsɪzəm/[2][3]) is a condition in which there is partial loss of pigmentation in an animal resulting in white, pale, or patchy coloration of the skin, hair, feathers, scales or cuticle, but not the eyes.[1] Unlike albinism, it is caused by a reduction in multiple types of pigment, not just melanin. [Wikipedia]
Noted in “Elusive snowy white giraffes filmed in Kenya,” Melissa Breyer, Treehugger.com:
Different subspecies of giraffes have different patterns. For example, Masai giraffes have spots that look like oak leaves while Rothschild’s giraffes boast large, brown splotches outlined by thick, pale lines. Kenya’s own reticulated giraffe, has a dark coat with very graphic shapes and well-defined narrow lines. Unless, of course, that reticulated giraffe happens to be white as a ghost.
Incredibly rare with what appears to be only a handful sightings in the wild captured on film, white reticulated giraffes are pale in color thanks to a genetic condition called leucism. Unlike albinism, in leucism skin cells don’t produce pigmentation, but soft tissues, like dark eyes, do.
And a video!
