What are the differences in appearance among the rhino species?
Among Asian rhinos, the greater one-horned rhino is the largest rhino species identified by its single horn and a gray-brown hide with skin folds that give it an armor-plated appearance. The Javan rhino looks similar to the greater one-horned rhino, but is smaller in size, has a much smaller head, and has less apparent skin folds. It is also known as the lesser one-horned rhino. The Sumatran rhino is the smallest and hairiest rhino. Its skin is reddish-brown in color, and it is the only Asian species of rhino that sports two horns.
Black rhinos are the smaller of the two African rhino species. Both black and white rhinos have two horns, and while there are a number of visual characteristics that differentiate them, the easiest way is by looking at the shape of the mouth. As grazers, white rhinos have a square upper lip, while black rhinos, who are browsers, have a hooked upper lip.
What are the biggest threats to rhinos?
Habitat loss and degradation and poaching are the main threats facing Asian and African rhinos. Despite a ban on international trade in rhino horn since 1977, illegal demand in Asia remains high and fuels poaching in both continents. The Sumatran rhino faces an additional threat: isolation. This species—of which less than 80 survive in about a dozen non-viable subpopulations in Indonesia—are simply too scattered to find mates to breed.
Why are rhinos so important to the environment?
Rhinos are ecosystem engineers in the places where they live. For instance, grassland habitats with access to water are important for greater one-horned rhinos, and they help maintain the health of these grasslands and the waterholes in which they wallow, which enables optimal conditions for other small herbivores that share the space with them. Rhinos also disperse the seeds of plants and fruit they’ve eaten through their dung.