The black caiman, Melanosuchus niger, grows to 3 meters (10 feet) in length, 250 kilograms (550 pounds) in weight and lives an average of 80 years in the South American Amazon region.

The species has been nearly hunted into extinction because of its skin, that fetches a high price on the black market.

The reptile's skin can be used almost in its entirety (with the exception of its sun-hardened back). Only the softer side skin of most alligators is used and sold.

The number of black Amazon caimans in existence is unknown, but the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) says that trade has threatened the reptile with extinction.

The first Bolivian attempt to end the illegal trade and legally market the caiman's skin was conducted by the cattle company El Dorado. The company established a caiman farm, but soon after the price commanded on the international market plummeted and business vanished.

As a result, the company donated 25 adult caimans and eight young specimens born in captivity to the Beni Biological Station in 1990. The protected area was created in 1982 by Spaniard Javier Castroviejo, the former director of the Doñana Biological Reserve.

The station at Beni, which was elevated to the rank of Biosphere Reserve in 1986, took in 33 caimans under special regulations and despite the concern that T'siman Indians would attempt to hunt the new arrivals.

The Indians use the abundant meat of the caiman, especially its long tail and also extract oil from the animal for medicinal purposes, it is a well-known remedy for respiratory problems.

According to the station's director, Juan Carlos Miranda, the adaptation of the whole group has been a success, some 100 specimens are believed to have been born since they were relocated to their new habitat 10 years ago.

"This group of caimans has adapted fully to the freedom of Normandia lagoon, in Beni Biological Station," Miranda said, adding that the infant reptiles had been born at a farm in Madidi National Park.

The lagoon is shallow, about 1.5 meters (5 feet) deep, but its surface stretches 12.5 square kilometers (4.8 square miles), making it the largest within the reserve area.

According to night counts, conducted every two months, only 12 of the 25 adults transported remain, apparently "as a result of a natural emigration through the rivers in the area."

"Those born in El Dorado station have become adults and have formed their own families in the lagoon. We believe that there are between 50 and 100 caimans in Normandia," the director for the research and protection center said.

The first nest found at the site, back in 1995, had 50 small caimans. Since then, others have been discovered around the lagoon.