They eat plants and fruit for the most part, but also insects, lizards and birds' eggs. They eat as a family, in a circle, facing out so they can keep a close watch for predators. They will take a bite and look around and repeat. They have a unique eye lid that allows them to look into the sun to watch for predators. (source)
Although they are terribly cute and look a lot like rodents, rock hyraxes are in a class all their own, more related to elephants and manatees than to the rabbits (which aren't rodents either) that my son thought they were like. They even have tusks which are elongated incisor teeth (rather than canine teeth).
Rock hyraxes have at least 21 different vocalizations, including trills, yips, grunts, wails, snorts, twitters, shrieks, growls, and whistles. Males also sing complex songs that can last for several minutes and serve a territorial purpose, like bird song. (source)
They are a small, careful animal. They lives in colonies, love to sun bathe and are also known by the name of rock badger, dassie or the cape hyrax.