Rhino, sometimes called Valve Rhino, is a rhinoceros who lives on Noah's Island. He came to the Island following the wreck of the ship that was transporting him and the other zoo animals to another zoo.
Soon after arriving on the Island, Rhino accidentally revealed how the Fireball's power could be used to steer the Island by moving a heavy stone with a hole in the middle, thus releasing some of the lava into the ocean. This impressed Noah, so Rhino was appointed to be the Island's Valve Operator, pushing the stone under Chief Engineer Nab's instruction.
Despite his great physical strength, Rhino appears to be rather unintelligent; although he can talk, he usually only mutters, 'pom, pom, piddle' to himself. Generally a fairly docile and peaceful character, he has occasional outbursts of anger when provoked.
After Rhino and the other Islanders arrived at Diamantina, he became the mate of a female rhino named Tallulah, who despite being much more intelligent, was perfectly happy to have long 'pom, pom, piddle' conversations with him.