Terrible trend

Africa's lion population plummets by two thirds in 50 years, study finds

"Only 25 percent remains of an ecosystem that once was a third larger than the continental United States," co-author Stuart Pimm, a Duke conservation ecology professor, said in a statement issued with the study.

"The situation in West Africa is particularly dire," the experts wrote, noting that human populations have doubled there over the last three decades. Fewer than 500 lions remain in West Africa, the study estimated.

The team and a panel of lion experts used the savannah data to refine estimates of lion populations, which had ranged between 20,000 and 40,000 across Africa. Their estimate: 32,000 lions remain, down from an estimated 100,000 in 1960.