September 22 is World Rhino Day. Everybody knows what the giant mammal looks like. But what else do you know? Here are some fun facts you may not have heard before which can help you understand more about this charming, but endangered animal.

When talking about rhinos, many people have Africa in mind immediately. However, three of five rhino species are endemic to South Asia.

All three rhino species of Asia, including the Indian rhino, the Javan rhino, and the Sumatran rhino, used to reside in China. Sadly, they are regionally extinct. Today, they only live in fragmented habitats in Nepal, India, Bhutan, Indonesia and Brunei. 

There are only 46-66 individuals of Javan rhinos, which means it is roughly 20 times rarer than the giant panda.

If you have seen white rhinos in local zoos, you may find they are gray, not white. The name is a mistranslation from Dutch to English: the English word "white" is actually a Dutch word "wijd", meaning "wide" and referring to the rhino's wide lips. In fact, another name of the white rhino is the square-lipped rhino, which is more accurate.

Well, the two rhino species have similar color, especially in the wild. So how can you tell them apart? The main difference is their lips: White rhinos have broad flat lips for grazing grass, whereas black rhinos have long pointed lips for eating leaves and foliage. By the way, the two species can mate and successfully produce offspring. 

The rhino is an odd-toed ungulate, which means it is more closely related to horses, zebras and tapirs, rather than other ungulates such as the buffalo, the bison or the hippo. 

Well, it may not be smarter than it looks. All rhino species reach or exceed one tonne in weight, but their brains are merely 400-600 grams.

A rhino's skin can be as thick as five centimeters, which provides perfect protection. Its hooves look just as rough as its body, however, their feet are vulnerable. If kept in the zoo, hard surfaces like concrete may hurt them.

A research of white rhino shows that their droppings are unique identifiers, enabling them to take one whiff of a dung heap and instantly know the animal's age, sex, and reproductive status. By this method, the former can decide if the latter is available for dating. By the way, they spray urine, too. A male rhino can spray several meters to leave a territory mark as well as a dating invitation. 

Adult rhinos have no real predators in the wild, except humans. However, a young calf may be prey to big cats, crocodiles, African wild dogs and hyenas.

The rhino horn, unlike those of other horned animals, does not have a bony core. It is completely made of exactly same material of human hair and fingernails. They have no medical value. China removed rhino horn from the official Chinese medicine pharmacopeia in 1993. 

(Cover image from VCG)

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