African lions need some good news. Recent decades have been rough on the iconic cats, which are now absent from 80 percent of their historic range. Their numbers have shrunk by 42 percent since the 1990s, and few remaining strongholds are safe.

Amid the widespread pressures of habitat loss and poaching, however, scientists have made a major discovery: a previously unknown population of 100 to 200 lions living in a remote swath of northwest Ethiopia and southeast Sudan.

The lions were found in Alatash National Park (aka "Alatish"), a nearly 660,000-acre preserve established by Ethiopia in 2006. The park attracts virtually no tourists, due to a mix of factors including its remoteness, harsh climate and low densities of large wildlife. Local people were reportedly aware of the lions, which may have been hidden there for centuries, but scientists were not.

The Alatash expedition was led by Hans Bauer, a renowned lion conservationist working for the Wildlife Conservation Research Unit (WildCRU) at Oxford University. Not only did Bauer's team find fresh lion tracks in the park, but their camera traps also captured indisputable photographic evidence. While they didn't venture into Sudan's adjacent (and larger) Dinder National Park, they say lions exist there, too.

"Lions are definitely present in Alatash National Park and in Dinder National Park," Bauer says in a statement from the conservation group Born Free USA, which helped fund the research. "Lion presence in Alatash has not previously been confirmed in meetings at the national or international level."

lion in EthiopiaA young male lion walks by the WildCRU camera trap in Alatash. (Photo: WildCRU/Born Free USA)

Only about 20,000 wild lions are left across Africa, and since most of their populations are in decline, they're listed as "Vulnerable" on the IUCN Red List of Endangered Species. Yet despite eluding formal detection for decades, the lions in Alatash were surprisingly easy to find, Bauer says. In addition to the footprints and photographs, his research team even got to hear lions roaring at night.

"Considering the relative ease with which lion signs were observed, it is likely that they are resident throughout Alatash and Dinder," Bauer adds. "Due to limited surface water, prey densities are low and lion densities are likely to be low, [so] we may conservatively assume a density in the range of one to two lions per 100 km2. On a total surface area of about 10,000 km2, this would mean a population of 100-200 lions for the entire ecosystem, of which 27–54 would be in Alatash."

If there really are 200 lions in Alatash and Dinder, they could raise their species' wild population by about 1 percent. That may not be a big difference, but as Bauer tells New Scientist, any positive news about lion numbers is noteworthy — especially in a place where the cats' presence had never been officially confirmed.

"During my professional career I have had to revise the lion distribution map many times," Bauer says. "I have deleted one population after the other. This is the first and probably the last time that I'm putting a new one up there."

map of Alatash National ParkA map of Alatash and Dinder national parks, showing the researchers' GPS track. (Image: WildCRU/Born Free USA)

Bauer suspects these lions are relatively safe, thanks to the wildness of their habitat and protection by Ethiopia's government. Poachers are still a risk, though, as he notes in a report about the expedition. "The main threat to the park is poaching, which is especially done by an ethnic group called 'Felata,' who are pastoralists originally from West Africa but now with Sudanese nationality," Bauer writes. "They are armed with modern and traditional weapons and spend several months per year inside the park, with their livestock. Scouts do not encounter them frequently, and fortunately no scout has ever become the victim of shooting by the Felata."

This may be one of the last discoveries of an "unknown" lion population, but thankfully it comes while there's still time to save the popular species. As Born Free CEO Adam Roberts points out, news like this can help spur action to preserve rare wildlife as well as the habitats on which their survival hinges.

"The confirmation that lions persist in this area is exciting news," he says. "With lion numbers in steep decline across most of the African continent, the discovery of previously unconfirmed populations is hugely important — especially in Ethiopia, whose government is a significant conservation ally. We need to do all we can to protect these animals and the ecosystem on which they depend, along with all other remaining lions across Africa, so we can reverse declines and secure their future."

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.