Rhinos live in home ranges that sometimes overlap with each other. Feeding grounds, water holes and wallows may be shared. The black rhino is usually solitary. The white rhino tends to be much more gregarious. Rhinos are also rather ill-tempered and have become more so in areas where they have been constantly disturbed. While their eyesight is poor, which is why they will often charge without apparent reason, their sense of smell and hearing are very good. They have an extended “vocabulary” of growls, grunts, squeaks, snorts and bellows. When attacking, the rhino lowers its head, snorts, breaks into a gallop reaching speeds of 30 miles an hour, and gores or strikes powerful blows with its horns. Still, for all its bulk, the rhino is very agile and can quickly turn in a small space. The female family groups are often visited by mature males checking for females in estrus. Several interrelated family groups may inhabit an area and know each other well. When they meet at watering holes and feeding places, they greet each other affectionately.