An unusual feeding strategy is that of the oxpeckers of Africa. They perch on living animals and glean parasites from the animals' hides. On furry animals, such as buffalo, giraffe, and donkey, these birds run their bills through the fur of the animal, using a scissors-like motion to extract ticks and lice from near the skin. When they pull the insect out to the end of the fur, they catch it and eat it. (On animals with bare hides, such as rhinoceros and hippopotamus, oxpeckers pick at any open wounds the animals happen to have, consuming blood and pus, and possibly keeping the wounds free of maggots.) Historically, rhinoceros and other large wild mammals have been among the favored hosts, but as the populations of large mammals in the African savanna have declined in modern times, the population and range of both red-billed and yellow-billed oxpecker have also changed, and now the birds will use donkeys and domestic cattle as hosts.