Although still highly vulnerable, there are more western lowland gorillas than previously thought, a new study finds. Over a 10-year period, scientists scoured 72,000 square miles of western equatorial Africa on foot patrols studying nests and other clues, reports the Guardian. Earlier estimates placed the gorilla population at 150,000 to 250,000. The new data puts the number of gorillas at 361,900, more than doubling the low end of the previous estimate. Scientists also tailed central chimpanzees in the same region and found them more plentiful than expected. They estimate the central chimp population to be 130,000, which is 10% to 80% higher than previously thought. The animals surveyed represent 99% of all gorillas in the world and about one-third of all chimpanzees.
Researchers found poachers to be one of the biggest threats to gorillas. Dominant males will stand up to hunters in an effort to protect their group and get shot in the process; the surviving males then kill the dominant male’s offspring, furthering the loss. Chimpanzees, on the other hand, "are cleverer and sneak away very quietly," says Fiona Maisels, a professor at the University of Stirling in Scotland and one of the 50 researchers on the project. They are also helped by cultural taboos against eating chimpanzee meat. Gorillas are still endangered—in fact, despite the revised population estimates, their numbers are trending downward by 2.7% annually, according to a press release, and most live in unprotected areas, leaving them vulnerable to hunters and illness. “Just because there are rather a lot of them does not mean they are not very, very vulnerable,” says Maisels. (A funky, green-haired turtle is in trouble.)