Aba (China) (AFP) - Born to a wild father and captive mother, nearly one-year-old twin pandas roll on the grass in a conservation base in southwest China, marking an important achievement in the preservation of the country's beloved animal.
Pandas are listed as a vulnerable species, but conservation efforts have helped reduce their danger of extinction.
The pair, named Hehe (meaning Harmony, pronounced Huh-huh) and Meimei (Happiness, pronounced May-may), were taken out of a dormitory on a bright sunny day this week to gulp milk and munch bamboo in front of some 100 visitors.
After eating, the cubs tumbled on the grass and played on a swing before they were returned to their cool dormitory for a noon nap.
The birth of Hehe and his younger sister Meimei, on July 25 last year in the Hetaoping panda base , was a success in China's attempt to introduce genes of wild pandas into the captive population.
The achievement was recognised by Guinness World Records on Wednesday.
The twins now live in the Shenshuping panda base in Sichuan province, with 70 other pandas.
There is a 50 percent chance for panda parents to produce twins, but making Hehe and Meimei was "very tough", said Liu Xiaoqiang, head of the Hetaoping panda base animal management department.
It took their mother more than a month to mate with a wild male after she was taken to a wild panda habitat. There was no human interference during the mating process.
"The genetic diversity of the captive population is still quite limited, so we need to introduce some fresh blood from the wild," Liu told AFP.
The birth of the twins is "a big step forward" in enriching genetic diversity and the success will allow researchers to make similar attempts in the future, Liu added.
Hehe weighs a robust 20.2 kilogrammes, and Meimei a healthy 17.6 kilos.
Giant pandas typically reach 100 kilogrammes when they are mature, said Li Feng, head of Shenshuping's panda kindergarten management department.
Li has been taking care of pandas for almost 15 years and has raised more than 100 cubs.
She knows the names of all the pandas in the conservation centre by heart, and can easily distinguish between Hehe and Meimei: the bigger brother has an irregular swirl on his pink nose, while the sister has a round face.
Hehe is a notorious troublemaker, famous for eating extraordinarily fast and stealing everyone else's food -- except his sister's.
Meimei, on the other hand, is very quiet and loves to follow her handlers around.
"I hope they can... grow up strongly, healthily and happily," Li Feng said, "so when they mature, they can bring more babies to our panda family."