The onager foal has been running off energy while enjoying his new habitat, zookeepers said.

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.