Black rhinos have terrible eyesight. Even so, these giant African herbivores easily fend off hungry lions and hyenas. “Their basic body plan has proved to be good enough to survive on a savanna full of large predators, being very large, thick skinned, big rapier-like horns.” Victoria University of Melbourne behavioral ecologist Roan Plotz. But those protective traits are no match for humans with guns. Today, the species is critically endangered largely due to poaching. But the rhinos may have an unlikely ally against poachers: the red-billed oxpecker. The chatty, sociable birds often hang out on the backs of rhinos, feasting on parasitic ticks. “And actually, research has shown that the tick is the favourite diet of an oxpecker. And if they feed on ticks, that is a good thing.” The birds also get nutrients by picking at sores on the rhinos’ bodies. Plotz suspected that the rhinos put up with this indignity because the oxpeckers make loud alarm calls whenever they see humans approach—giving the rhinos an early warning to flee.