The first two months in the lives of a pair of giant panda bear twins have been captured on film and released as they celebrate their first birthday at a Spanish zoo.

The small bears can be seen evolving from what appear to be tiny hairless rats into fluffy, black eyed pandas in the space of eight weeks.

After ten days, they began to develop hair and after one month, their sex was determined and they were confirmed to be male.

The twins, who are known as You You and Jiu Jiu, were born at The Madrid Zoo in Spain’s capital city on 6th September, 2021.

Their first birthday coincided with the 50th anniversary of The Madrid Zoo along with ‘Giant Panda Month’ which is celebrated in September in Spain.

The panda bear (Ailuropoda melanoleuca) also known as the giant panda, is a black and white bear species that is native to China.

At birth, cubs weigh between 85 to 140 grams (3 to 5 ounces), while in the wild, males weigh between 85 to 125 kilogrammes (190 to 275 pounds).

Bamboo shoots and leaves typically make up 99 per cent of their diet while pandas in captivity are known to feed on honey, eggs, oranges and bananas along with other specially prepared panda food.

In celebration of the twins’ birthday, the zoo planned to hold meetings and educational talks with zookeepers along with a live feeding session, face painting for kids and bamboo craft workshops.

Pandas are no longer considered an endangered species due to the efforts of conservationists but are still listed as a vulnerable species on the IUCN red list.

Their threats include habitat loss and a very low birth rate, both in captivity and in the wild.

The zoo added: “The little pandas have been the protagonists of the 50th anniversary of the Zoo since their birth, a year ago, as a focus of international repercussion in the media around the world.

“Since then, their evolution has been vertiginous and from barely 200 grams they have gone to 30 kilos in their first year of life.”

The young pandas are already eating their first bamboo leaves and will not stop playing with each other while testing the patience of their mother, a panda known as Hua Zui Ba.

The statement added: “Interestingly, all the giant panda births in Madrid have occurred between the end of August and the first fortnight of September.

“It seems that the climatic conditions influence the moment in which the female panda chooses the implantation of the embryo that is most conducive to the development and survival of the offspring.”