In just one day tens of thousands of people have watched a stirring video of joyful and tentative laboratory chimpanzees getting their first taste of sunlight.

“They hugged, they laughed,” said Michael Aufhauser, founder of the Gut Aiderbichl Affen-Refugium near Salzburg in Austria which has taken in and built new enclosures for the chimps.

“Imagine, one is 30 years imprisoned in an elevator, and then suddenly the door opens,” he told the German television station RTL which filmed the moment.

“They have never learned to climb. They had been placed as infants in the laboratory.”

Some, like the 37-year-old chimp Susi, had been in a lab for three decades.

In the video, the first three chimps crowd a doorway, heads swivelling back and forth, as they absorb the sights and smells and feel of outdoors. The trio hug, glance around warily, then venture out as a fourth and then a fifth chimp appears in the doorway.

Liberated, they stroll around the grass gleefully.

More than 78,000 people have viewed the video on YouTube in one day; more than 12,000 have recommended it on Facebook from the RTL site.

The chimps are part of the first 10 of 38 former lab animals undergoing a slow process of learning to live in freedom, Aufhauser told RTL.

The chimp Xsara is the only one so far that hasn’t ventured into the outdoor enclosure, the animal sanctuary says. Susi, meanwhile, was “introverted and inflexible” as a lab animal but now “puts us in awe” with her enthusiastic embrace of the outdoors.

Created in 2006, the sanctuary started with a dozen rescued horses and now also provides shelter for donkeys, mules, ponies, cattle, sheep, pigs, cats and dogs.