Luke, a leucistic ellipsen waterbuck calf, was born in the South African exhibit at the San Diego Zoo Safari Park on September 6, 2014. What in the world is that, you ask?
An ellipsen waterbuck is a 400-pound (180 kilograms), shaggy African antelope. Waterbuck are grazers and escape into lakes and rivers to avoid predators. Lions and hyenas are not good swimmers, but the waterbuck’s oily coat is water repellent and makes them buoyant as they swim away from these carnivores. Ellipsen waterbuck are distinctive because they have white rings on their rump, like a bulls-eye. This “follow-me” mark allows a waterbuck to identify its herd members.
Luke is unique because he is leucistic (pronounced loo KISS tick). Leucism is a genetic condition where pigment cells don’t develop properly. The word leucism comes from the Greek word leukos, meaning white. Albinism is often mistaken for leucism, but albino animals are only missing the melanin pigment. Leucistic animals are missing all pigments in either patches or over the entire surface of their bodies. Albino animals commonly have red eyes because they lack the melanin to color the irises and turn them opaque, so the blood vessels show through the translucent irises. Leucistic animals have normally colored eyes. Leucism is a well-documented phenomenon. Piebald horses are partially leucistic. The white tigers seen around the world in zoos in the 1980s and1990s demonstrate recessive genes for leucism.
Luke is not alone. His condition is rare but not unheard of, and it shouldn’t affect his development in any way. Luke’s mother, a traditionally colored ellipsen waterbuck, was pregnant for eight months before giving birth to Luke in the exhibit. Luke looks like the negative of his mom: instead of a chestnut-brown coat, Luke’s is bright white. Instead of a white bull’s-eye ring on his rump, Luke has a black ring. Instead of white eyebrows, Luke’s are black. In fact, if you look at a photo negative of Luke and his mom, Luke would look normal and his mom would look leucistic.
Initially, keepers were worried that Luke’s mom would reject him for looking different. Instead, she has been fiercely protective of him. Ellipsen waterbuck calves are “tuckers” for two to four weeks, meaning the mother tucks her offspring in a hiding place so she can forage. Luke’s mom has been hiding him in various spots throughout the Safari Park field exhibit. But she has been more attentive than the mothers of most tuckers and has isolated herself from the rest of her herd to spend time with him. She even chased away the curious herd of Cape buffalo that came to investigate her unusual baby.
The next time you visit the San Diego Zoo Safari Park, see if you can spot Luke and his mom during an Africa Tram tour.
Elise Newman is a Caravan Safari guide at the San Diego Zoo Safari Park. Read her previous post, Rhino Calf Makes Own Rules.