The U.S. is helping to save an elusive and endangered species of gorilla in West Africa. The Fish and Wildlife Service and the Wildlife Conservation Society have developed a five-year plan to ensure the survival of the primate.

　　Dirck Byler of the U.S. Fish and Wildlife service said the Cross River gorilla is not as well-known as its relatives in other parts of Africa.

　　Critically endangered

　　"There's two different species of gorilla actually. There's the western gorilla and the eastern gorilla. And the one that people are most familiar with are the eastern gorillas, specifically the subspecies known as the mountain gorilla, which is found in Rwanda and Uganda and the Democratic Republic of the Congo. The western gorilla is found in the western part of the Congo Basin in countries such as Cameroon, Gabon, northern Republic of the Congo. And then one of their subspecies is called the Cross River gorilla. And this is the most endangered gorilla species today," he said.

　　In fact, the Cross River gorilla has been classified as "critically endangered" by the International Union for the Conservation of Nature, the IUCN.

　　"It's much more endangered than the mountain gorilla is and unfortunately hasn't received as much attention over the years," said Byler.

　　Byler, program officer for the Great Ape Conservation Fund at the U.S. Fish and Wildlife Service, said it's believed there are only a few hundred of the gorillas left.

　　"We don't really have a good estimate of what the population was before, but it was likely many thousands. But over the last hundred years as human population has grown in this area they were hunted down to a very small level of 250 to 300 individuals scattered across 13 little pockets on the border of Nigeria and Cameroon," he said.

　　Just 10 to 15 years ago, the Cross River gorilla was thought to be either extinct or nearly extinct.

　　"With actually a lot of support from the U.S. Fish and Wildlife Service and the work of conservation NGOs like the Wildlife Conservation Society we've been able to get a handle on where the remaining populations exist. So our understanding from a scientific point of view has increased dramatically," he said.

　　Survival of the subspecies

　　Two new national parks have opened in Cameroon that offer safe haven for the gorilla. One is the Kagwene Gorilla Sanctuary, which was created with a grant from the service. The other is the Takamanda National Park, which was converted from a forest reserve.

　　Part of the five-year plan to save the Cross River gorilla is to have local communities act as guardians for the primates.

　　Byler said, "Many of the gorilla populations still lie outside protected areas and national parks and will never probably be included in national parks. And so through working with local communities to curtail hunting and to provide alternatives to hunting in many of these places we think we can get a handle on hopefully stabilizing the population and even increasing it."

　　So how many Cross River gorillas would there have to be in order for the species to be considered safe? Byler said it's difficult to set what's called a goal population.

　　"Maybe doubling the population in the next 20 or 30 years would be tremendous. And whether that would be enough to ensure its long term sustainability is in question, but it sure would be great progress if we could achieve that. The reproductive rate of gorillas is very slow and it takes a long time to actually increase a population," he said.

　　The U.S. Fish and Wildlife Service is able to offer its assistance in Africa and elsewhere through the Great Ape Conservation Fund. It was established by Congress in 2000. The fund allows the service to offer conservation grants ranging from $50,000 to $100,000.