SINGAPORE - To commemorate World Rhino Day, which falls on Sept 22, visitors to the Singapore Zoo are being encouraged to donate their nail clippings to a "Jar of Nails" as a gesture of support for conservation efforts for these animals.

Here are five interesting facts about rhinos according to the International Rhino Foundation:

- White rhinos might look slow and bulky but they can reach top speeds of 42kmh - the same speed as a car travelling on suburban roads.

- The closest living rhino relatives are the tapir, horse and zebra. They are all have hooves with an odd number of toes on their rear feet.

- A group of rhinos is called a crash.

- White rhinos are not actually white in colour. They were named after the Afrikaans word "wyd," which means "wide", and is a description of their mouth. However, early English settlers in South Africa misinterpreted "wyd" for "white".

- Rhino pregnancies last 15 to 16 months, second only to elephants, whose pregnancies can go up to two years.