The “extremely rare” Cairngorm Reindeer calves, which were born two weeks ago, are only the second known case in the world of twin reindeers surviving birth.
According to the owners, which is Britain’s only free-roaming herd, previous sets of twins have been stillborn or died shortly after birth.
The twins’ mother, Lulu, 12, is one of the herd’s older females and is said to be taking the birth “in her stride”.
Adorable pictures show the twins at just two hours old lying down by their mother’s side.
Fiona Smith, reindeer herder and centre manager, said: “Thirty years ago we had twins, one was stillborn and the other survived for 12 hours.
“Since then we have had two sets (2008 and 2015) but both were stillborn so you can imagine our shock when we found them both alive and well.
“Their mother Lulu is one of our older females in the herd, at 12 years, and she is taking everything in her stride and not batting an eyelid at the two little bundles following her.
“She loves them both and lets them feed, however, we are giving her a helping hand by offering them a top-up of bottled milk as we feel she hasn’t got enough to sustain two.”
The calves spent their first two weeks in a mountain enclosure where they were born.
Herders at the centre have been visiting the pair first thing in the morning and the last thing at night every day to make sure they were getting enough milk.
They were being supported to suckle from Lulu in their first few days but now the calves are growing well.
Fiona added: “They are coming on leaps and bounds, and feeding themselves.
“We, of course, must remain realistic as this is extremely rare with only one other known case of twins being born in the world: in Finland in 2010.
“We will do our best by both them and Lulu, making sure she gets extra feed, browse and attention.
“Summer time is crucial for keeping an eye on reindeer with biting insects causing illnesses which the twins will be more susceptible to so their first six months are going to be a rocky road.
“However we feel they have rallied through their first two weeks so this amazing news can go public.”