Near Extinction :  

There are five surviving species of Rhinoceros (family Rhinocerotidae). All are endangered, and all but the Square Lipped (White) Rhino are in imminent danger of extinction. Mercilessly hunted for their horns, rhinos have disappeared from all but a few isolated locations in Africa and Asia. Today fewer than 11,000 rhinos remain - less than 10 percent of the 1970 population. 

The most imperiled species is the Javan Rhino. At one time this animal roamed throughout southeast Asia, Sumatra and Java; today fewer than 100 survive in the Ujung Kulon peninsula reserve in western Java, Indonesia. The Sumatran Rhino has not faired much better. Once found throughout southeast Asia, Sumatra and Borneo, only a handful remain in peninsular Malaysia, and there are rare and unconfirmed sightings in Borneo.  

Range :  

Formerly found throughout most of Africa and south and southeast Asia, only scattered populations of rhino survive.  
  

Phylogenetic (evolutionary) Order :  

Over 30 different genera of ancestral rhinos have been identified in the fossil record. These animals once ranged throughout Eurasia, North America and Africa. Rhinoceros evolved from a hornless herbivore, smaller than a Tapir, during the Oligocene (approximately 40 million years ago). One lineage evolved into the Woolly Rhinoceros (Coelodonta antiquitatis) - a long-haired, thick-coated species that survived into the last ice age. Remarkably preserved specimens, with skin and hair intact, have been found in Siberian permafrost. The contemporary African rhinos come from a separate branch (subfamily Dicerotinae). The Sumatran Rhino is probably the closest to the phylogenetically older forms.  

Physical Characteristics :  

All rhino species alive today are grayish in color with at least one horn protruding from their snout. With the exception of the Sumatran, all rhinos are essentially hairless with hair only on their tail and ears. While young Sumatran Rhinos are covered with coarse hair, older animals have almost none. To cool off and remove insects from their skin, rhinos enjoy wallowing in mud and taking dust baths. The African "Black" and "White" Rhinos probably get their names not from their skin color, but from the color of the dust on their bodies after taking mud or dust baths.  

At 4,500 to 5,000 pounds (2,040 to 2,260 kg) and 5.6 to 6 feet (171 to 183 cm) in height, White (Square Lipped) Rhinos are the largest land mammal after the Elephant (Hippos weigh more, but are shorter). Adult Square Lipped Rhinos' lower horn averages 24 inches (60 cm) long in adults. Because a rhino's horn continues to grow throughout its life, mature adults have been recorded with horns 5 feet (150 cm) in length. The natural life span of African rhinos is 35 to 50 years. The smallest rhinos are the Sumatran which reach a height of 3.6 to 5 feet (110 to 150 cm).  

Rhinos possess noticeably poor eyesight, and may lose sight of their young at close range (150 feet / 45 meters). However, they posses good hearing and a keen sense of smell. When alarmed, rhinos can gallop at up to 30 mph (50 kph). When frightened, rhinos will sometimes charge toward the disturbance yet stop short of contact. Onlookers often interpret this behavior as aggressive, though the rhino may simply be attempting to get a closer look at the intruder.  

The illegal trade in rhino products :  

The decimation of rhino populations is almost entirely a result of poaching to meet demand for rhino horn in Arab and Asian countries. With no natural enemies in the wild, adult rhinos seldom hide and so are easy targets for poachers. Although most countries ban international trade in rhino products, the black market for horn has created enormous financial incentives for poachers, traders and distributors to continue their trade. In Taiwan, one pound (half a kilo) of Asian rhino horn can fetch $10,000 to $30,000 (US), while a pound of African rhino horn sells for about $1,000 to $1,500 (US). It is estimated that during the 1970s an average of 17,600 pounds (8,000 kg) of rhino horn was traded illegally in global markets each year. Though these numbers decreased to about 6,600 pounds (3,000 kg) a year during the 1980s, this still translates into at least 1,300 rhino deaths per year. (source: World Wildlife Fund) 

 The "Power" of the Horn :  

What is it about the rhino's horn that is so desirable? After all, the rhino's horn is just keratin, a fibrous material somewhat like densely packed hair or the hooves of cattle. In a number of Asian cultures powdered rhino horn is believed to cure fevers and have aphrodisiacal powers. In Yemen, rhino horn has been carved into ceremonial dagger handles for centuries. There is no scientific evidence that powdered rhino horn will do anything other than hurt the rhino population and put a dent in one's wallet.  

Diet :  

All rhinos are herbivores. The forest dwelling Asian species and the African Hooked Lipped are well adapted for browsing. These species use their almost beak-shaped mouths to grasp and pull foliage for consumption. The Square Lipped Rhino is a more evolved grazer, with a flatter mouth suited to eating grass.  

Reproduction :  

Under favorable conditions, female rhinos mature around their seventh year and thereafter will give birth to a single calf every three to four years. Gestation lasts 15 to 16 months. Rhino calves weigh roughly 145 pounds (65 kg) at birth and can stand within minutes. Because calves are vulnerable to hyenas and lions, mothers often hide their young in thickets for several weeks after birth. Mothers will occasionally adopt orphaned calves.  

Behavior :  

Rhino's are usually sedentary and solitary. While males maintain territories, they sometimes allow subordinate males within their home range. Rhinos mark the boundaries of their territories with urine and "dung middens." A territorial male will always defecate on the same 20 or so piles of dung, then slowly scatter the pile with slow kicks.  

Rhinos are seldom aggressive, with the exception of territorial males. Most confrontations are mild, with each party sizing up the other, until one slowly backs away. Males sometimes joust with their horns, though stabbings are infrequent.  

Conservation Efforts :  

The rhino is protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), an agreement among more than 120 nations to eliminate illegal trade in animals and plants and their parts and associated products.  

The U.S. government imposed wildlife trade sanctions on Taiwan in 1994 for that country's illegal trade in rhinoceros as well as tiger parts and products -- the first time the U.S. government has taken such action on another country to penalize illegal trade in critically endangered wildlife.