Officials at the oldest zoo in the world have been thrilled with the recent birth of three endangered megabats in the rainforest enclosure.

The three large flying fox offspring delighted zookeepers at the Schoenbrunn Zoo, in the city of Vienna, Austria, when they were born.

Video footage from the zoo shows the bats, Pteropus vampyrus, cuddling up with their mum as they curiously explore their new surroundings with their eyes wide open on Wednesday, August 16.

Head of the Zoological Department Anton Weissenbacher said in a statement: 'Large flying foxes spend most of their lives hanging upside down, even the offspring are born in this position.

'Female large flying foxes not only work against gravity, but also use their wings to form a kind of hammock to catch the young animal after birth.'

The animal - considered one of the largest bat species in the world due to its 1.70-metre-wide (5.6 feet) wingspan - is reportedly native to south Asia.

Listed as 'endangered' on IUCN's Red List of Threatened Species, these giant bats reportedly spend their night sleeping and their days looking for food.

However, unlike other bats that use echolocation, large flying foxes depend on their keen sense of smell and large eyes to feed themselves.

Animal keeper Samantha Cloer said: 'Large flying foxes feed mainly on fruit, pollen, nectar and flowers.

'Since they can travel long distances in search of food, they are important seed dispersers and make a valuable contribution to the reforestation of forests.'

In turn, little ones are reportedly sucked by their mums for about four to six months, after which they begin eating solid foot and attempt flying on their own.

The zoo revealed that interested individuals can visit the species on the upper floor of the rainforest enclosure as the ground floor is undergoing thorough renovation due to high humidity levels.

They added: 'The basic renovation and redesign of the house should be implemented by the end of next year. After the reopening, visitors can look forward to new animal highlights.'