The King used a stethoscope to help give a penguin a health check during a trip to London Zoo.
Charles, who was accompanied by the Queen, braved the scorching heatwave and joined zoo vet Stefan Saverimuttu as he checked over a Humboldt penguin during the visit on Thursday.
Dozens of penguins, about two feet tall, gathered to greet to royals as the couple approached their enclosure in Camden.
Crouching down, Charles used a red stethoscope to check the heartbeat of a penguin named Lannister as the bird patiently sat perched on a rock.
Camilla, using a blue stethoscope, also bent down to join in.
“Lannister sounded perfect and Lannister was very well behaved for the King and the Queen,” Mr Saverimuttu said.
“They’re very endearing,” the King said about the birds.
Asked how the couple’s veterinary skills had been, the vet said Charles and Camilla had taken to it “very well”.
“Both of them were really enthusiastic about the penguins,” he added.
“Penguins have a bit of a beak on them so I think if you’ve never met one before, they might be a bit intimidating, but neither the King or the Queen was intimidated in the slightest and they went straight in and gave it a go and they did really well.”
The pair also took part in laser training exercises used to encourage and observe movements in the penguins including swimming and diving.
The laser pointers mimic the sparkling scales of fish, which penguins are known to chase, and allow vets to spot any health concerns.
Standing next to a glass wall with a view into the blue pool, Charles and Camilla, tried unsuccessfully for a couple of minutes to capture the penguins’ attention.
One penguin eventually swam up to the King’s laser pointer as he laughed and exclaimed: “That’s the only one that’s noticing.”
Charles wore a blue suit with an animal-themed tie and sunglasses, while Camilla, carrying a cream parasol, chose a white Fiona Clare dress adorned with wildlife including elephants and deer.
During the trip, which celebrated the 200th anniversary of the Zoological Society of London (ZSL) conservation charity, the couple paused to meet a Galápagos tortoise named Polly and help feed her some snacks.
The 31-year-old tortoise was presented with a watermelon decorated with the number 200 and flowers.
Using metal tongs, the Queen fed some of the greenery to Polly while the King offered her some leaves by hand.
Polly largely ignored the King’s offering prompting Charles to jokingly ask her keeper whether the tortoise was on a “diet”.
In the zoo’s Tiny Giants area, Charles spoke to staff about the conservation work done by the ZSL to protect Partula tree snails from extinction after they were wiped out by an invasive carnivorous snail species.
Asked whether he would like to paint one of the tiny creatures, the King laughed and said: “I’ve painted a few things in my time but never a snail.”
Holding a small paint brush, Charles placed a dot of purple paint on two of the snail’s shells which will help to track them once they are released into the wild in French Polynesia.
“So this is special snail varnish is it?” the King joked.
The visit was Charles’s first tour of the zoo as the ZSL’s patron, having visited the attraction for the first time as a one-year-old to see Brumas, a new born polar bear cub.
Since 1828, every monarch has been patron of the society.
The zoo was founded by the ZSL that year in London’s Regent’s Park, becoming the world’s first scientific zoo.
During the tour, the couple heard about the creation of a new wildlife centre, announced by ZSL to mark the anniversary.
The centre will be used to investigate diseases in animals, train wildlife vets, track how diseases spread between species and support conservation projects around the world as well as providing new veterinary facilities for the animals at ZSL’s two zoos – London and Whipsnade.
