About the Northern White Rhinos
From The San Diego Zoo's Animal Bytes

"Rhinoceroses get their name from their most famous feature: their horns. The word rhinoceros comes from the Greek rhino (nose) and ceros (horn). The five types of rhinos are the Sumatran, Javan, black, white, and Indian. Javan rhinos and Indian rhinos have only one horn, while Sumatran rhinos, black rhinos, and white rhinos have two.

What they all have in common are large heads, broad chests, thick legs, poor eyesight, excellent hearing, and a fondness for rolling in the mud. How the white rhino came to be called "white" is uncertain since it is gray. One account says that South Africa's early Boer settlers called it wijde, Dutch for "wide," which could refer to the wide lip or the size of the animal.

The Wild Animal Park has the largest crash of rhinos and the most successful captive breeding program for rhinos anywhere in the world. When the worldwide population of southern white rhinos numbered less than 2,000, a male at the Park sired 50 babies."