The Hunt for a Lost Bat

The obsessive people who track down disappearing species are their own variety of rare—sparsely found across a wide geographic range, in all sorts of habitats.

In January, 2019, a multinational team of biologists set out into the rain forest of southwestern Rwanda, in search of a near-mythical bat that they thought might be extinct. The Hills’ horseshoe bat—agacurama in Kinyarwanda—hadn’t been seen in forty years. Scientists had caught and recorded it only twice, in 1964 and 1981, roughly five miles apart, in a forest reserve named Nyungwe. But then conflict and war, culminating with the genocide in 1994, devastated the region. Many of Nyungwe’s research and tourist facilities were destroyed. Subsistence agriculture, sometimes undertaken by people fleeing conflict, along with things such as logging and mining, caused the forests surrounding Nyungwe to largely disappear.

Paul Webala, a Kenyan wildlife biologist and one of the expedition members, had started work in 2013 on a monograph of the bats of Rwanda. “Not much was known,” he told me. “Records were old” and lacked echolocation data. The Hills’ horseshoe bat was the only Rwandan bat species, out of fifty-four found in the country, which the International Union for Conservation of Nature (I.U.C.N.) had listed as critically endangered. Webala wondered whether it was lost simply because no one had gone looking for it. He recruited the help of Julius Nziza, a Rwandan wildlife veterinarian for Gorilla Doctors, to conduct reconnaissance surveys. By then, the government had made Nyungwe Forest a national park; its four hundred square miles had become the largest protected tract of Afromontane rain forest in the Albertine Rift, a hotspot of endemism that stretches from Uganda to Zambia. Many of its animals and plants are found nowhere else on Earth. After more than a year of searching, however, Webala and Nziza started to think that the Hills’ horseshoe bat was found nowhere on Earth. During the course of two expeditions, they surveyed ten sites and found eight other bat species, but not Hills’. Was it extinct?

A million species currently face extinction, “many within decades,” a landmark biodiversity report, authored by more than three hundred scientists, reported in 2019. The rate of plant and animal extinction is already as much as hundreds of times higher than it has averaged over the past ten million years, and is expected to accelerate. At the same time, “biological communities are becoming more similar to each other,” the report’s summary said, leading “to losses of local biodiversity, including endemic species, ecosystem functions and nature’s contributions to people.” Nature, in its increasing homogeneity, is going the way of the American fast-food chain.

To address the catastrophe, delegates from the world’s nations recently met in Geneva to renegotiate the Convention on Biological Diversity, an international treaty first enacted in 1993. Progress was notable on the “30×30” initiative—to protect thirty per cent of Earth’s land and seas by 2030—which scientific consensus indicates is the absolute minimum needed to help curb global biodiversity loss. A majority of participating countries announced their commitment to the goal. “There has never been this much support for this level of conservation in history,” Brian O’Donnell, the director of the Campaign for Nature, told me. But countries will still need to formally adopt the global target—and a new, binding biodiversity framework—at the fifteenth Conference of the Parties, or cop15, now anticipated to start in August, in China. For leaders from the developing world, which will be disproportionately responsible for conserving biodiversity, appropriately ambitious financing commitments from donor countries remain in question. “That will be the biggest obstacle to achieving an ambitious global agreement,” O’Donnell said.

Lost-species quests can seem like wild-goose chases, but as Barney Long, the senior director for conservation strategies at the nonprofit organization Re:wild, told me, you can’t save what you don’t know is there…