Our planet is home to five rhino species – the black rhino and the white rhino, which live in Africa, and the Sumatran, Javan and Indian rhinos, which inhabit Asia's tropical forests and swamps. World Rhino Day is celebrated on September 22 every year to call for public attention to this giant endangered creature.

Talking about rhinos, many people think of their horns. Their name "rhinoceros" even comes from Ancient Greek words, meaning "nose horn." Sadly, their iconic horns bring harm to them by making them the target of poachers. Rhino horns are either made into luxurious decorations or used in traditional medicine, even though they are made of the same substance found in our fingernails. 

It's estimated that there are now less than 29,000 rhinos left in the wild, compared to 500,000 at the beginning of the 20th century, according to Save the Rhino International. The population of Sumatran rhino and Javan rhino are even both below 80.

More about rhinos:

Ten things you might not know about rhinos

What will be the fate of Asian rhinos?

Keep the five rhino species alive

For more:

International Red Panda Day: Protect our cute fluffy friends

International Vulture Awareness Day: Protect nature's clean-up crew

International Orangutan Day: Protect our close relatives

What you don't know about painted wolves

International Whale Shark Day: Protect the gentle giants in the sea

(All images via CFP, designed by CGTN's Liu Shaozhen)

(If you want to contribute and have specific expertise, please contact us at nature@cgtn.com.)