Neil Aldridge / Yellow-billed oxpecker (Buphagus africanus) perched on the back of an African buffalo (Syncerus caffer) on the banks of the Chobe River, Chobe National Park, Botswana.

Neil Aldridge / Warthog (Phacochoerus africanus) with a Yellow-billed oxpecker (Buphagus africanus) on its back, nuzzling its mother at a waterhole, Chief's Island, Okavango Delta, Botswana.

Richard Du Toit / Greater kudu (Tregalaphus strepsiceros) covered in Yellowbilled oxpeckers (Buphagus africanus) rear view, Kruger National Park, South Africa.

Pal Hermansen / Yellow-billed oxpecker (Buphagus africanus) on African buffalo (Syncerus caffer), Masai Mara, Kenya

Sharon Heald / Yellowbilled oxpecker {Buphagus africanus} on Zebra Moremi WR, Botswana, Africa

Denis-Huot / Impala (Aepyceros melampus), and Yellow-billed oxpeckers (Buphagus africanus) Masai-Mara game Reserve, Kenya.

Denis-Huot / Black rhino (Diceros bicornis), with Yellow-billed oxpeckers (Buphagus africanus) sitting on back and feeding on insects, Masai-Mara Game Reserve, Kenya

Ingo Arndt / Cape Warthog (Phacochoerus aethiopicus) adult male / with Yellow-billed Oxpecker (Buphagus africanus) adult sitting on head and calling, Masai Mara National Reserve, Kenya

Frederique Olivier / Tracking shot of an African buffalo (Syncerus caffer) grazing and walking through a herd, with Yellow-billed oxpeckers (Buphagus africanus), Serengeti NP, Tanzania.

Frederique Olivier / Panning shot of a herd of African buffalo (Syncerus caffer), with Yellow-billed oxpeckers (Buphagus africanus), Serengeti NP, Tanzania.

Charlie Summers / Masai giraffe (Giraffa camelopardalis tippelskirchi) male with red-billed (Buphagus erythrorhynchus) and yellow-billed (Buphagus africanus) oxpeckers on neck, Ruaha National Park, Tanzania.

Jen Guyton / Common eland (Taurotragus oryx) with Red-billed oxpeckers (Buphagus erythrorhynchus) and yellow-billed oxpecker (Buphagus africanus) standing on the savanna in the Maasai Mara Reserve, Kenya.