Keepers at Exmoor Zoo in Devon were treated to their own festive miracle after two capybara pups were born on Christmas Day.

The zoo delayed announcing the births to ensure the new arrivals survived, but the unseasonably mild weather has proved perfect for the pups.

Capybaras are part of the same rodent family as guinea pigs, and while the babies are currently the size of their smaller cousins, adults reach about the size of a sheep – measuring 18 inches high and 4ft long, and weighing about 70kg.

Native to the swamps and rivers of the Amazon and South America the record-breaking high temperatures of the past few days has been “perfect”, for the capybara, Exmoor Zoo said.

They will also be at home in any heavy January rains – their Latin name, Hydrochoerus hydrochaeris, means “water hog”.

Zoo director Danny Reynolds said: “New arrivals and births at the zoo are always exciting and even better getting a present like this on Christmas day.”

The pups added to the zoo’s December birth tally with a caracal lynx kitten born earlier in the month.

The wild cat is native to Africa, the Middle East and Central Asia can reach up to 20 inches high at the shoulder, and can leap 12ft to seize small birds in mid-flight.