The document provides information on the appearance, habitat, and population statistics of rhinoceros species. It notes that rhinos can be found in Asia and Africa, have thick armor-like skin, and range in size. The most vulnerable species are the Javan and Sumatran rhinos, with populations of less than 40 and 400 respectively. Poaching is a major threat due to demand for rhino horn in traditional medicines, though the horn is composed of the same material as human hair and nails.