A Czech military plane is transporting four Przewalski mares to Mongolia for reintroduction into the wild, part of Prague Zoo’s long-standing programme to save the Mongolian wild horse. The zoo’s spokeswoman said the horses left Prague airport aboard a CASA military plane on Saturday. Przewalski’s horse is a rare subspecies native specifically to Mongolia. It became extinct in the wild 40 years ago and Prague Zoo has played a major role in saving the horse, breeding it and gradually returning it to its natural environment. Between 2011 and 2014 the zoo has sent 15 horses to a nature reserve in the Mongolian steppe where they have started breeding successfully.