The cost of that complacency became clear when the gold mine was discovered. The Gabonese government sent the military to close the mine and root out the poachers, but the damage had already been done. In 2013, following a quick pilot study, scientists estimated that between 50 and 100 elephants were being killed daily, and that between 44 and 77 percent of Minkebe’s elephants had already been slaughtered since 2004.

“If we do not turn the situation around quickly, the future of the elephant in Africa is doomed,” wrote Lee White, the British-born head of the Gabon National Parks Agency. “Our actions over the coming decade will determine whether these iconic species survive.” Now, after a more rigorous survey of the elephant numbers, White, Poulsen, and others have found that their work is even more urgent than they had realized.

Savannah elephants can be counted from the air, but forest elephants are so elusive that biologists literally have shit to go on: They have to trudge through the undergrowth, counting piles of elephant dung. They then used two separate methods to convert dung densities into elephant numbers—one that estimates the rate at which dung decays, and another that also factors in the effect of rainfall. Satisfyingly, both methods led to the same conclusions. Depressingly, those conclusions were worse than the team had expected.

They estimated that in 2004, there were between 32,800 and 35,400 elephants in Minkebe. But in 2014, there were just 6,500 to 7,400 left. In just one decade, poachers had killed around 25,000 forest elephants—between 78 and 82 percent of the park’s population. “It was an enormous shock,” says Poulsen. “To be quite honest, I would have guessed that other studies had overestimated the loss. I was expecting a decline, but I didn’t expect it to be that high.”

The dung decline fit with other lines of evidence. Guards have stumbled across hundreds of actual carcasses. Poachers have been caught with rifles and tusks. A genetic study traced the DNA of seized ivory back to elephants living in the Minkebe region.

That this should have happened in Gabon is a tragedy. The country has among the best conservation policies in Africa. They have set aside large tracts of protected space. They pay wildlife rangers on time. In response to the Minkebe crisis, President Ali Bongo Ondimba raised the status of the forest elephant to “fully protected”, doubled the budget of the National Parks Agency, created the National Park Police, passed new legislation to criminalize commercial ivory poaching, and increased prison terms for ivory traffickers. In 2012, he set fire to the country’s entire stockpile of seized ivory—the first such act for a Central African country. For three days, a 10,000-pound pyramid of tusks burned in symbolic defiance.