File photo shows guards stand near the female northern white rhino called Najin inside an open enclosure at Ol Pejeta Conservancy in Nanyuki, Kenya, April 17, 2015.(Photo: Xinhua)

Thirty endangered white rhinos arrived in Rwanda on Monday after a long journey from South Africa in a Boeing 747, conservationists said, hailing it as the largest single transfer of the species ever undertaken.

The majestic animals, which can weigh up to two tons, traveled some 3,400 kilometers from South Africa's Phinda Private Game Reserve as part of a program to replenish the species' population, decimated by poaching since the 1970s. 

Once plentiful across sub-Saharan Africa, white rhino suffered first from hunting by European settlers, and later a poaching epidemic which largely wiped them out.

The rhinos began their 40-hour journey to the new home in Akagera National Park in eastern Rwanda following months of preparation, said African Parks, a charity headed by Britain's Prince Harry which is involved in the exercise. 

"We had to tranquilize them to reduce their stress, which is itself risky, and monitor them," said African Parks' CEO Peter Fearnhead, calling the project a success. 

The animals were transported in a chartered Boeing 747 and were placed in two grassy enclosures - each the size of a soccer stadium - after arriving in the park.

Later they will be allowed to roam the expansive park, authorities said. 

"This will provide an opportunity for them to grow in a safe environment from South Africa where three are killed per day by poachers," said the park's regional manager Jes Gruner. 

Wildlife transfers are not without risks. In 2018, four out of six relocated black rhinos died a few months after arriving in Chad. 

The southern white rhino, one of two subspecies of white rhino, is now considered endangered with only about 20,000 individuals remaining, according to the World Wildlife Fund. 

It is classified as near-threatened by the International Union for Conservation of Nature.

The northern white rhino has all but vanished, with only two females left alive.

Scientists are attempting to save the species from extinction by harvesting eggs from the younger of the two animals, Fatu, and using sperm from two deceased males to create embryos in an unprecedented breeding program, which is their last chance at survival.

AFP