The relationship between a rhinoceros and an oxpecker is a mutualistic relationship, meaning that it benefits both parties, in which the oxpecker eats burrowing insects from the hide of the rhino. This frees the rhino from the constant irritation and itching of these pests while providing a meal for the oxpecker.
The rhino has a very sensitive hide, which makes burrowing insects, such as ticks, especially irksome. Without the oxpecker, the rhino spends a lot of time trying to scratch or rub off the insects. The oxpecker has its own problems, such as poor eyesight, making it difficult to spot insects on its own. Together, the oxpecker gets an easy meal and the rhino gets free grooming. Furthermore, the oxpecker warns the rhino of approaching danger by shrieking.
The oxpecker is not the only animal that has this sort of relationship with the rhino. The cattle egret performs a similar role. On the other hand, the oxpecker does not limit itself exclusively to rhinos. It also rides on and eats ticks off zebras.
Many other species share mutualistic relationships. One example is the relationship between bees and flowers. Flowers provide bees with valuable nectar. While a bee gathers nectar, the pollen from a flower sticks to the bee. The bee then transfers this pollen to another flower for fertilization, and both the bee and the flower benefit.