White rhinos -- with their square lip -- are grazers, eating mainly grass and herbs.
On the other hand, black rhinos -- with their hooked lip -- are browsers, eating mainly leaves and twigs from trees. The prehensile lip of a black rhino resembles a miniature elephant trunk, in that it helps them to reach vegetation as well as bring it into their mouths. Amazingly enough, they can even eat thorny plants such as Acacia (even where the stems have long sharp thorns) with no problem! You would think that the thorns would cut into their lips, gums, and tongue, but actually the rhinos are highly skilled at rotating the stem in such a way that they do not hurt themselves at all! I suppose it also helps that they have large strong teeth....
Did you know you can hear a black rhino eating from a distance of up to 500m? That's some loud chewing!
Rhinos have no incisors or canines, only molars. Therefore, when they bite into a stem or twig, they do so from the side of their mouth. However, their flexible, prehensile lip helps them to stuff the food into their mouths, be it leaves, herbs, or twigs. Hand-raised babies can also use it to stuff a human finger, hand, or arm into their mouths, so they can suck on it! (Remember they have no teeth in the front of their mouths, but they do on the sides.)
