A rhino's horn is made up of keratin - the same protein which forms the basis of our hair and nails.

The Javan and greater one-horned rhinos only have one horn, whereas all the other rhino species have two horns.

Their horns grow continuously during their lifetime – the white rhino's horn can grow 7cm every year – and the record length is 150cm long!

Sadly these amazing features are the reason for the rhino's extinction. The rhino has been poached for many, many years and is now close to extinction because of its horns. These days, most rhinos are under 24-hour surveillance to protect them against poachers.