The university says this picture proves the bridges are working (Pic: Ajrian Osman)
Orang-utans facing extinction in a region of Borneo are being helped by a project involving Cardiff University.
The animals around the Kinabatangan river in Sabah, Malaysia, previously used trees to cross river tributaries.
But deforestation and logging have led to the small rivers becoming barriers which the animals are unable to cross.
Researchers at the university's Danau Girang field centre in the area have helped create rope bridges for the orang-utans to use.
Six rope bridges were built as part of a project run by the Kinabatangan Orang-utan Conservation Project (KOCP) and the Sabah wildlife department.
The university said a photographer had taken a picture, which proved the bridge project was successfully reconnecting isolated orang-utans.
A young male orang-utan is pictured crossing a small tributary which is said to be the first hard evidence that the bridges are making a difference.
The bridges are considered important because research has suggested the area's orang-utans are facing extinction.
Dr Benoît Goossens, of Cardiff School of Biosciences and director of the Danau Girang field centre, said: "Genetic studies have been carried out by the university, Danau Girang, KOCP and the Sabah wildlife department.
"The data from these shows that the populations of orang-utans in the Lower Kinabatangan river areas are estimated to go extinct in our lifetime if they are not reconnected through schemes like the rope bridges.
"Similar bridges will be set up at tributaries in the vicinity of the field centre. It will be supported by the Borneo Conservation Trust of Japan and monitored by our staff and students."
The field centre in Sabah is a research and training facility managed by Cardiff University and Sabah wildlife department.