Max Planck scientists discover new sensory capability in a mammal
Animals can use varying sensory modalities for orientation, some of which might be very different from ours. Some bird species for example take the polarization pattern produced by sunlight in the atmosphere to calibrate their orientation systems.
Now researchers from the Max Planck Institute for Ornithology in Seewiesen, Germany, and Queen’s University Belfast have discovered with colleagues from Israel that a night active mammal, the greater mouse-eared bat, has the capability to orient using polarized light. These bats use the polarization pattern of the evening sky to calibrate their inner compass.
In the course of evolution manifold sensory systems developed which allowed animals varying possibilities to perceive their environment. Many insect species for example, but also some fish, amphibians, reptiles and birds can see polarized light. Polarized light forms as a result of sunlight being scattered in the atmosphere.
The sky’s polarization pattern can be used by animals as a compass, well-known examples being the orientation of honeybees, desert ants or migratory birds. Even humans can perceive polarized light to some degree.
Subject to certain conditions we can see a so called Haidinger’s brush, a diffuse yellowish form, which however, has no known function. The fact that mammals can also make use of this sensory perception was not known so far.
An international team of bat researchers including Stefan Greif from the Max Planck Institute for Ornithology, Seewiesen, and from the Queen’s University Belfast now found exactly that.
Their study shows that the greater mouse-eared bat (Myotis myotis) can use the polarized light of the evening sky to calibrate their orientation system, which is based on the Earth’s magnetic field.
The researchers caught 70 female mouse-eared bats in a cave in North-eastern Bulgaria. During dusk they exposed half of the bats to a polarization direction which was shifted 90 degrees from the natural spectrum.
The other half of the animals was placed in similar experimental boxes but with a natural polarization direction. Long after nightfall the bats were brought to two different sites some 20 kilometres away from their home roost. There they were released after the scientists equipped them with tiny radio transmitters to follow their flight trajectories on their way back to the cave.
Those animals that experienced a 90 degrees shifted polarization pattern at sunset, vanished in a direction which deviated about 90 degrees from the control group. With this simple experiment the researchers showed for the first time that bats can use the polarization pattern of the evening sky to calibrate their inner compass for orientation. The precise mechanism however, is still unknown so far.
“Further behavioural and physiological studies are necessary to understand this fascinating new sensory capability”, says Stefan Greif, lead author of this study.
Stefan Greif | Max-Planck-Institute
27.05.2015 | Okinawa Institute of Science and Technology (OIST) Graduate University
Seeing the action
27.05.2015 | University of California - Santa Barbara
The only professorship in Germany to date, one master's programme, one laboratory with worldwide unique equipment and the corresponding research results: The University of Würzburg is leading in the field of biofabrication.
Paul Dalton is presently the only professor of biofabrication in Germany. About a year ago, the Australian researcher relocated to the Würzburg department for...
Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.
Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...
Development and implementation of an advanced automobile parking navigation platform for parking services
To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...
The world's first electrical car and passenger ferry powered by batteries has entered service in Norway. The ferry only uses 150 kWh per route, which...
On Tuesday, 19 May 2015 the research icebreaker Polarstern will leave its home port in Bremerhaven, setting a course for the Arctic. Led by Dr Ilka Peeken from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) a team of 53 researchers from 11 countries will investigate the effects of climate change in the Arctic, from the surface ice floes down to the seafloor.
RV Polarstern will enter the sea-ice zone north of Spitsbergen. Covering two shallow regions on their way to deeper waters, the scientists on board will focus...
20.05.2015 | Event News
18.05.2015 | Event News
12.05.2015 | Event News
27.05.2015 | Power and Electrical Engineering
27.05.2015 | Health and Medicine
27.05.2015 | Physics and Astronomy