A rhino's food chain is rather simple, starting with the primary grasses or shrubs it consumes, and ending with the scavengers and decomposers that consume it after death. Rhinos are pure herbivores, and therefore have only one link on the food chain below them. They are also extremely large, aggressive and well-protected, and so have few natural predators.
Rhinos are almost purely herbivores, so they occupy only the second trophic level on their food chain, that of the primary consumer. Unlike most primary consumers, however, they have no significant natural predators. The exceptions are very young or very old animals, which do suffer predation by lions and hyenas at times. However, as the second largest animals on land after elephants, with extremely tough, thick hides and large horns, mature rhinos are almost impossible for any natural predators to kill.
A rhinoceros will eventually die, however, and once this happens scavengers such as hyenas and vultures consume much of the carcass. Fungi and bacterial decomposers consume what remains after the scavengers are done. These scavengers and decomposers, also known as detrivores, are not counted as part of any particular food chain, however, since they consume a significant portion of almost all species.