|
We always new that bats are amongst the super-elite of the planet's coolest animals, but it seems they're even better than was thought:
As if one supra-human sense - echolocation - was not enough, it turns out that bats have another. Like birds, they can navigate by sensing Earth's magnetic field. The only other mammals known to do this are naked mole rats and Siberian hamsters.
Ten big brown bats (Eptesicus fuscus) were exposed to artificial magnetic fields that twisted their perception of magnetic north by 90 degrees, either to the east or the west. The bats were then released 20 kilometres north of their usual roost, along with five control bats that had not been exposed to magnetic fields. The control bats soon found their way home, but the 10 magnetised bats remained lost for days because their internal magnetic compass had been reset. They all flew towards what they thought was south, but of course it wasn't (Nature, vol 444, p 702).
"It's the first demonstration that bats use a magnetic compass," says team leader Richard Holland of the University of Leeds, UK, and Princeton University.
The team tricked the bats by exposing them to a magnetic field at sunset, assuming that they would do the same as birds and recalibrate their inner compass with reference to the position of the setting sun. Holland says it's likely that all bats have a magnetic sense.
|