Every day 20 unusual lions greet visitors at a tiny animal park in Addis Ababa, Ethiopia. These lions, which have spent generations in captivity, are not like most African lions (Panthera leo leo). For one thing, they are slightly smaller than the wild lions found elsewhere on the continent. For another, the males carry distinctive black manes that extend from their shoulders to their stomachs and are much darker than those sported by other lions. And finally, new research reveals that these rare lions also have unique DNA, although not enough to declare them a separate species or subspecies.

"I think they are genetically distinct enough to justify conservation efforts," says Michael Hofreiter, professor of evolutionary biology and ecology at the University of York in England and one of the authors of a study about the Ethiopian lions' DNA that was published in the October European Journal of Wildlife Research. The research team came to its conclusions after running DNA tests on 15 of the zoo's 20 lions, which revealed that the lions possess both microsatellite and mitochondrial DNA that is distinct from other African lions. (Because the five remaining lions were all juvenile progeny of the others, they were not tested.)

Hofreiter says these animals are not only genetically different but also phenotypically unique, indicating that their behavior is different from other lions. If any lions like them still exist in the wild, "they probably occur in open forest habitat, rather than in savanna landscapes," he says.

The lions at the zoo all descend from a collection owned by Haile Selassie, the emperor of Ethiopia from 1930 to 1974 and the messiah of the Rastafarian movement. Selassie founded the zoo in 1948 with five males and two females—animals reportedly captured in southwestern Ethiopia, although no evidence backs up their exact source. Luckily, despite the low founder population, Hofreiter says neither the DNA nor the appearance of the animals shows any signs of inbreeding.

In a University of York press release, lead author Susann Bruche, who conducted the research with the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, but is now with Imperial College London, echoed the need for preserving these lions' singular genetics. "A great amount of genetic diversity in lions has most likely already been lost, largely due to human influences. Every effort should be made to preserve as much of the lion's genetic heritage as possible."

The authors have called for renewed efforts to conserve this one-of-a-kind population. The first step, they recommend, is establishing a formal captive breeding program. "At the moment they are hardly bred because of a lack of space," Hofreiter says. He reports that a new zoo is being built nearby that will give the animals significantly more room. "It will have the possibility to keep two larger groups and allow the lions to live in more natural groups than is currently the case." The Leipzig Zoo, which also contributed to the DNA study, is consulting on the construction of the new zoo.

The current zoo is hardly sufficient for breeding efforts. The lions are kept in tiny cement and steel cages, with few opportunities for exercise or enrichment. Comments on TripAdvisor call the cages "soul-killing" and "horrific." This 2011 video showcases the minimal conditions in which the lions live:

Conditions might be even worse behind the scenes. In 2006 the BBC reported that the zoo routinely poisoned lion cubs and sold their corpses to taxidermists because the institution lacked the money or space to care for the animals. Hofreiter discounted the report, although he points out that problems have existed. "As far as we know, the story that cubs were killed is wrong, but it is true that previously cubs sometimes died soon after birth because of inadequate keeping conditions in the old zoo, and we cannot exclude that some of these were sold for preparation," he says.

In addition to the new zoo and, it is hoped, a better breeding program, the researchers plan to follow up on rumors that more of these rare lions might still be in remote parts of the country. "There are areas in Ethiopia where these lions probably still exist in the wild, so we aim in the long run to obtain field samples and genetically type these," Hofreiter says. "The political situation is not simple, however, and for all strands of research we would require more money than we have currently available."

Photos by Joerg Junhold and Klaus Eulenberger, Leipzig Zoo. Used with permission