The remarkable footage shows near-threatened European pond turtles returning home after spending the winter at the world's oldest zoo.

Videos captured at the SchoenbrunnZoo, in Austria's capital Vienna, depicted zookeepers bringing the turtles back to their native Danube-Auen National Park on March 26.

They can then be seen dipping into the warm waters at the national park after their home was remodelled over the winter period as part of a project called 'Biodiversity in the Alpine Carpathian Corridor' aimed to secure their habitat.

Schoenbrunn Zoo Director Stephan Hering-Hagenbeck said: 'In the zoo, we were able to simulate the natural winter conditions using climate chambers.

'What is particularly important is constant temperatures until the animals are gradually woken up from their winter torpor.

'Our experienced team of carers looked after the turtles and regularly checked their health.

'As a long-standing partner of the national park in protecting European pond turtles, we are pleased that we were able to help here too.'

National Park Director Edith Klhauser added: 'These measures are part of a species protection project that is financed by the BMK's biodiversity fund.

'The interventions are intended to prevent the water from freezing to the bottom in winter, which would be fatal for the turtles that overwinter there.

'Fish species such as the dogfish, which was once considered extinct in Austria, also benefit. We are very grateful that Schoenbrunn Zoo supported us by overwintering the turtles.'