This is the moment two adorable South American sea lion pups explore their enclosure after being born just days apart at the world's oldest zoo.

The births took place at Schoenbrunn Zoo in Vienna, Austria, after the pups arrived in early and mid-July, with the zoo announcing the double arrival on 30th July.

The youngsters can be seen staying close to their mothers inside a specially created mother-and-pup section of the seal enclosure, where visitors are already able to watch them.

In the video, the two pups splash into the water, nursing from their mothers, and cuddle closely with them inside their enclosure.

Zoo director Dr Stephan Hering-Hagenbeck said the pups would remain separated from the adult male for a little longer to give them time to settle.

He explained: "It will be a little while before they join the male because we want to give the animals enough time and peace."

He added: "This is also a special period for our male sea lion. During the breeding season, he eats very little food, which also happens in the wild. That is why the training sessions and the commented feeding demonstrations are currently taking place in an adapted format."

The zoo said the pups still preferred to stay close to their mothers, but that would soon change as they became more confident.

Hering-Hagenbeck said: "With a little patience, visitors will be able to watch the two pups explore their surroundings more and more and discover them through play."

The youngsters have already completed their first swimming attempts, as South American sea lions are able to swim from birth.

Each pup weighed around nine kilogrammes at birth and still has a long way to go before reaching the impressive size of their mothers, which weigh about 145 kilogrammes, or their father, who weighs around 430 kilogrammes.

Rupert Kainradl, the zoo's head of zoology, said the species had evolved remarkable adaptations for life in and around the sea.

He explained: "South American sea lions can close their ears and nostrils while diving."

He added: "Their blood and muscles contain the protein myoglobin, which allows them to store much more oxygen, enabling them to stay underwater significantly longer than humans."

Kainradl said research had also shown that the animals could improve their ability to hold their breath depending on the environment they lived in.

He said sea lions living in southern Chile, where they regularly make deeper and longer dives, were able to store proportionally more oxygen in their blood.

The longest dive recorded during the study lasted 12 minutes.