![]() ![]() Why Is This Zebra Unusually Pale? Zebras are best-known for their distinctive black and white stripes, but why is this zebra so pale? Hint: It’s not an albino. Experiments in the field, for instance, have shown that biting flies don’t like landing on striped surfaces. Unfortunately for Tira, recent research by Larison and others has suggested that zebra stripes evolved to deter against biting flies-one of five theories that have been posed over the years, along with camouflage and temperature regulation. “I have seen several photos of foals with this specific pattern over the years, but only one photo-from the ‘50s-in which the individual was either a juvenile or adult.” Hurdles to survival ( Read about a rare white giraffe and other unusually pale animals.) “Research on other species has shown that, while it is harder for a predator to target an individual in a group, it is easier if an individual is different,” she says. Tira’s future is likely uncertain-most zebras with such unusual coloration probably don’t survive long, Larison notes. In the case of Tira and other pseudomelanistic zebras, Barsh believes the melanocytes are all there, but the melanin itself, for some reason, does not manifest correctly as stripes. In zebras, melanocytes are uniformly distributed throughout their skin, so that a shaved zebra would be completely black. ( Learn more about why animals are black and white.) “There are a variety of mutations that can disturb the process of melanin synthesis, and in all of those disorders, the melanocytes are believed to be normally distributed, but the melanin they make is abnormal,” Greg Barsh, a geneticist at the HudsonAlpha Institute for Biotechnology, says by email. Specialized cells called melanocytes produce melanin, the red, yellow, brown, or black pigment that determines hair and skin cell color in mammals. Keeping track of such equine aberrations is useful to science as part of a broader goal to monitor changes in species and how they’re managed by local communities. ![]() Zebras also experience other unusual color variations, such as partial albinism, which was seen in an extremely rare “blond” zebra photographed earlier this year in Tanzania’s Serengeti National Park. (See pictures of zebras in National Geographic.) Tira and these other foals have a condition called pseudomelanism, a rare genetic mutation in which animals display some sort of abnormality in their stripe pattern, says Ren Larison, a biologist studying the evolution of zebra stripes at the University of California, Los Angeles. Similar foals have been seen in Botswana’s Okavango Delta. Zebra stripes are as unique as fingerprints, but Tira’s odd coloration could be the first recorded observation in the Masai Mara, according to Liu. Antony Tira, a Maasai guide who first spotted the foal, named him Tira. “At first glance he looked like a different species altogether,” Liu says. Photographer Frank Liu was on the search for rhinos recently when he noticed the eye-catching plains zebra, likely about a week old. Talk about a horse of another color-a zebra foal with a dark coat and white polka dots has been spotted in Kenya’s Masai Mara National Reserve. The eye-catching animal, seen in Kenya’s Masai Mara National Reserve, likely has a genetic mutation called pseudomelanism.
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