A three-year study of the hearing ability of penguins at the German Oceanographic Museum in Stralsund in collaboration with partners in Germany and Denmark presented its findings during an online final conference in April. This project lays the scientific foundation for future research on hearing in diving birds and contributes to our understanding of the extent to which seabirds require protection from underwater noise in the wild.
As part of the three-year “Hearing in penguins” project, international scientists studied penguin behaviour above and below water in order to determine how sensitive penguins are to natural and anthropogenic noise. For the first time, scientists were able to train penguins to respond upon perceiving various sounds at low levels. This psychoacoustical approach at the German Oceanographic Museum is at the forefront of research into penguin hearing in air. Audiograms are being generated that show the frequency and intensity thresholds above which penguins can hear.
Collaborators at the University of Southern Denmark have developed a non-invasive method to make audiograms of penguins in the wild using a cap fitted with electrodes.
At the Natural History Museum in Berlin, collaborators have created diverse communication formats to represent the problem of underwater noise. In addition to an information platform, the researchers have developed an audiogram database with which scientists can compare the audiograms of penguins with those of other animal species. Furthermore, adaptive changes in inner ear anatomy of penguins are being investigated in museum specimens via CT scans. These anatomical studies suggest that penguins are also able to hear when diving. In line with these findings, researchers at the University of Southern Denmark have observed that penguins at Odense Zoo avoid even relatively quiet acoustic signals underwater. "This clearly shows that diving birds are also sensitive to underwater sounds and need to be protected from underwater explosions, construction and geophysical exploration in the same way as whales and seals," explains Dr Michael Dähne, project leader at the German Oceanographic Museum.
The results of the research project funded by the German Federal Environment Agency were presented online during an English-language final conference on 28 and 29 April 2021 during the “Week against noise in the sea”. Scientists at the German Oceanographic Museum have applied for a project extension in order to be able to complete the psychoacoustical measurements and electrode cap experiments.