In the Gobi Desert, where Argali roam, a group of Mongolian researchers are working to conserve the wild sheep populations. For more than 20 years, Denver Zoological Foundation in cooperation with Mongolian researchers has been helping to protect this iconic species by working in partnership with local herders and their families in Ikh Nart National Reserve. It is the longest-running study of Argali anywhere in the world.

Argali can weigh up to 400 pounds, which makes them roughly twice the size of North American bighorn sheep. With a light brown coat, the animals are known for their impressive, spiraling horns—an Argali ram’s corkscrew horns can grow up to six feet long.

By 2001, the Argali population in Mongolia had declined even further. Fewer than 15,000 animals remained in the country. Despite the success in reducing poaching at Ikh Nart, illegal hunting persisted in western Mongolia. And Argali faced a new threat: domestic livestock. Currently, there are 30,000 and 40,000 livestock at Ikh Nart, and maybe 700 to 800 Argali sheep.

Despite its forbidding climate, Mongolia’s Ikh Nart Nature Reserve is home to a diverse array of wildlife, including wolves, saker falcons, Siberian ibex goats, cinereous vultures, vipers and Argali—the largest wild sheep in the world. Ikh Nart, which is located nearly 200 miles southeast of Mongolia’s capital city Ulaanbaatar and comprises 160,000 acres, remains one of the last remaining Argali strongholds in the world.