Communication
Rhinos use several forms of communication. Due to their bad eyesight and solitary nature, scent marking is often used to identify themselves to other black rhinos. Urine spraying occurs on trees and bushes, around water holes and feeding areas. Females urine spray more often when receptive for breeding. Defecation sometimes occurs in the same spot used by different rhinos, such as around feeding stations and watering tracks. Coming upon these spots, rhinos will smell to see who is in the area and add their own marking. Less commonly they will rub their heads or horns against tree trunks to scent-mark.
Read more about this topic: Black Rhinoceros, Behavior