Chester Zoo has celebrated the birth of what it said was one of the rarest animals on earth.

The Cheshire attraction said the Persian onager was born to mum Azita after a year-long pregnancy.

Onagers hail from the semi-desert regions of Iran, and are related to domestic donkeys.

The foal was named Jasper, whose Persian meaning relates to treasure.

Conservationists at the zoo said there are less than 600 surviving wild onagers, but the birth “of the leggy youngster” could help safeguard the species from extinction.

Mike Jordan, animal and plant director at Chester Zoo, said the zoo was “delighted” with the birth of Jasper.

Mr Jordan said Jasper is “doing very well” and added that “mum Azita is doing a fantastic job of nurturing and bonding with her new charge”.

“He’s full of energy and enjoys playfully kicking up sand as he races around his habitat”, Mr Jordan added.

Wild asses were once found in abundance across the deserts of Mongolia, China and Iran, but now very few species remain.

Onagers only survive in two small, protected areas in Iran, a Chester Zoo spokesman said.

According to conservationists, the species has suffered at the hands of illegal poaching, overgrazing, drought, and disease passed from farm animals.

Their numbers have plummeted by more than 50% in the last two decades.

The species has been listed as endangered by the International Union for the Conservation of Nature (IUCN).

“With numbers having declined so rapidly in the wild, and the species now teetering on the edge of existence in Iran, it’s sadly very possible that onagers could become extinct in the wild within our lifetime,” added Mr Jordan.