European marsh turtles have returned home after a 'winter vacation' at Vienna Zoo.

Footage shows the 38 reptiles arriving at the Donau-Auen National Park, also in Vienna, Austria, on March 26.

Upon their homecoming, the turtles immediately submerged into the familiar waters near the Auerlebnisgelande Schlossinsel.

Conservationists said the reptiles' habitat was excavated and redesigned over the cold months as part of the 'Biodiversity in the Alpine Carpathian Corridor' project.

Due to these renovations, the marsh turtles could not hibernate at the bottom of the water as usual and were therefore brought to the zoo in late autumn.

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

'Consistent temperatures are particularly important until the animals are gradually awakened from hibernation.

'Our experienced care team has looked after the turtles and regularly monitored their health.

'As a long-standing partner of the National Park in the protection of European marsh turtles, we are pleased to have been able to help here as well.'

Stephan added the water areas around the Schlossinsel harbour not only the only native turtle species in Austria but also other animals such as insects, amphibians, and fish.

To ensure long-term suitable habitats for these species, the Muehlgang and the Muehldumpf, parts of the Fadenbach watercourse near Orth an der Donau, were structurally deepened.

National Park Director Edith Klauser added: 'These measures are part of a species conservation project funded by the Biodiversity Fund of the Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation, and Technology.

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

'Fish species such as the burbot, which was once considered extinct in Austria, also benefit. We are very grateful to the Vienna Zoo for supporting us by overwintering the turtles.'

The Schlossinsel is an important site for environmental education. A class from the local school Volksschule Orth an der Donau was allowed to be present at the return of the marsh turtles and help bring the animals to the water. During the process, Maria Schindler, the head of the marsh turtle protection project, told the class many interesting facts about these fascinating animals.