The buffalo and eland carried their passengers on their backs,

Oxpeckers only rarely roosted on non-giraffe species at night,and when they did, they perched on the animals' backs or sides

Oxpeckers only rarely roosted on non-giraffe species at night,and when they did, they perched on the animals’ backs or sides.(Snapshot Serengeti and the Serengeti Lion Project)

as well as on their sides. However, the birds preferred a different location on giraffes, which Palmer referred to in her research paper as “armpits” — a word she now concedes is a euphemism.