Przewalski’s horses have made their way back to the Kazakh plains after almost 200 years, as part of an ambitious effort to return the world's last wild horses to their natural habitats.

These endangered sandy brown horses once roamed extensively through Central Asia. Named after Russian geographer Nikolay Przewalski, who discovered them in the late 1800s, their presence had dwindled to a small area in western Mongolia by then.

The Prague Zoo in the Czech Republic, which oversees the species' studbook, plans to reintroduce them to central Kazakhstan's Altyn Dala region, a vast stretch of grasslands and wetlands covering around 7,000 square kilometers (2,700 square miles).

The first group of seven horses arrived in early June. On Thursday, four more landed in Arkalyk. In total, roughly 40 more are expected to be introduced within the next five years.

“This marks a historic event. The seven Przewalski’s horses we transported here via two CASA planes are the first of their species to be seen in central Kazakhstan in centuries,” stated Miroslav Bobek, director of Prague Zoo.

Czech military aircraft transported the horses - one stallion and six mares - on flights from Prague and Berlin to the Kazakh city of Arkalyk. They then traveled seven hours by truck, accompanied by zoo keepers.

The horses will spend a year in an acclimatization enclosure to learn how to locate water and sustenance during the harsh winters of the steppes.

Przewalski’s horses had vanished from the wild by the late 1960s but survived in captivity.

They have been reintroduced in China and western Mongolia, where the population now totals 850. In Kazakhstan, the reintroduction is a part of conservation efforts, as these horses eat various grasses and help disperse seeds.

“It is vital to have these wild horses around,” said Albert Salemgareyev, lead specialist for the Association for the Conservation of Biodiversity in Kazakhstan.