Red-billed oxpeckers on an impala in Mpumalanga, South Africa

© Heini Wehrle/Minden Picture

Relationship status: It's complicated

By posing for us, are these red-billed oxpeckers imposing on this impala? Well, science hasn't quite decided on this one. The relationship between parasite-eating birds and hoofed mammals was once considered a textbook example of mutualism, with oxpeckers cleaning up the ticks and fleas that bug the bigger beasts. Which is what we'd like to think is going on here.

But research in the last few decades suggests that oxpeckers only seek out ticks that have had their fill of mammalian blood - which makes their benefit to impalas and similar animals minimal. So, is our impala friend getting cleaned for free or being taken for a ride? We'll let you decide.