Demand for rhino horn over the past 50 to 60 years, however, made the black rhinos an increasingly rare sight in Africa. Trade in rhino horn peaked in the 1960s and '70s, when huge quantities were shipped to Middle Eastern and Asian markets.
In Yemen, for example, rhino horn is carved into handles used in daggers called jambiyas. The daggers are carried as a status symbol, according to Richard Emslie, a scientific officer of the World Conservation Union's African Rhino Specialist Group, based in KwaZulu-Natal, South Africa.
Emslie said that during the 1970s, 3,000 to 4,000 kilograms (6,600 to 8,800 pounds) of rhino horn entered north Yemen illegally each year.
During the last decade, however, Yemen has imported just 70 kilograms (150 pounds) of rhino horn a year on average, Emslie said. He attributes the decline to conservation programs and a drop in disposable income in Yemen.
Many Asians, meanwhile, continue to use rhino horn as a traditional medicine for feverdespite modern clinical trials, which show rhino horn has little or no effect in reducing fever, according to Emslie.
Steps to Recovery
By 1980 poaching and habitat destruction had reduced black rhino numbers to around 14,000. In 1991 the population stood at just 3,450, then plummeted in 1995 to an all-time low of some 2,400.
But the conservation agencies of South Africa, Namibia, Kenya, and Zimbabwewhich harbor most of Africa's black rhinoshave managed to halt the animal's decline.
The countries have been aided by conservation experts at WWF, the Frankfurt Zoological Society, the U.S. Fish and Wildlife Service, and the Southern African Development Community.
Emslie, the World Conservation Union scientist, said a number of law-enforcement practices put in place in the 1990s have helped decrease black rhino poaching in those countries:
Antipoaching patrols have intensified and been better targeted.
Park rangers and antipoaching units now have a much better idea of how to collect evidence and secure crime scenes to increase the chances of bringing a conviction against suspected poachers.
The development of "networks of informers" has helped authorities press charges against poachers.
Penalties for poaching have increased in some countries, where prison sentences of five to ten years have recently been assigned.
Emslie added that breeding programs have played a key role in black rhino conservation efforts.
Program managers, for example, work to keep individual populations at the optimal size for a given area of habitat. Smaller rhino populations put females in top breeding condition to churn out calves. That's because, left unchecked, black rhino populations can grow to the point where females are competing with other rhinos for food. As a result, females take longer to conceive again after producing each calf.
To avoid this breeding slowdown, authorities move rhinos from healthy populations to seed new populations or bolster old ones in other areas of the animal's range.
Emslie likens the practice to a form of investment banking "with the rhino populations like a portfolio of shares," he said. "We move animals around to maximize the gains from our investment."
Conservationists hope the black rhino can emulate the success story of its cousin, the white rhino.
Emslie cautions that there is no room for complacency, noting that experts have observed a slight increase in rhino poaching over the last two yearsthe same period in which black rhino numbers also grew quickly.
"[Poaching] still represents less than a total of 40 to 50 animals of both [African] rhino species per year, and has not prevented African rhino numbers continuing to increase," Emslie said.
"It is critical that poaching remains kept at manageable, low levels," he said. "Poaching is a little like a wildfire. If you keep a lid on it when it is small, it stays manageable."
For more rhino news, scroll down.
SOURCES AND RELATED WEB SITES