Red fox's secret hunting weapon revealed
Watch a fox dive headfirst into 3 feet of snow and emerge with a snack. Scientists weren't sure how the animal did this amazing feat until they discovered a pattern in the pouncing.
Tue, Dec 10, 2013 at 11:22 AM
The highly adaptable red fox can be found throughout the Northern Hemisphere and is considered the most widespread carnivore on the planet.
But while it might be commonplace in many parts of the world, the red fox has an ability that's anything but ordinary: It uses Earth’s magnetic field to hunt.
Red foxes feed primarily on small rodents, and unlike most mammals, they can hear low-frequency sounds extremely well. When a fox is hunting, it listens intently and can pick up on tiny sounds — including the sound of a vole scampering beneath 3 feet of snow.
Even when its prey is out of sight, the fox can pinpoint the animal's exact location. It then leaps into the air and strikes from above, a technique known as mousing.
But scientists don’t think this amazing ability is due to the fox's extraordinary hearing alone.
Jaroslav Červený spent two years studying red foxes in the Czech Republic, and his team observed 84 foxes perform almost 600 mousing jumps.
They discovered that the animals mostly pounced in a northeastern direction and they were more likely to make a kill if they jumped along this axis — even when prey was hidden by snow.
When they pounced to the northeast, the foxes killed on 73 percent of their attacks. If they jumped in the opposite direction, the success rate was 60 percent. In all other directions, only 18 percent of pounces resulted in a kill.
Červený suspected the foxes were using their sensitive hearing and the Earth’s magnetic field to plot their trajectory.
He described the foxes as using the magnetic field as a "rangefinder." As a fox follows the sound of its unseen prey, it's searching for that sweet spot where the angle of the sound matches the slope of the planet's magnetic field.
When the fox finds that spot, it knows its exact distance from its prey and can calculate exactly how far to jump to catch it.
If scientists are correct, the red fox is the first animal known to use a magnetic sense to hunt and the first to use the planet’s magnetic field to estimate distance.
Many animals — including birds, sharks, ants and cows — can sense magnetic fields, but they use this ability to determine direction or position.
While scientists don't know for sure how a fox's magnetic sense works, Hynek Burda of the University of Duisburg-Essen in Germany has a hypothesis.
He suggests that a red fox could see a ring of "shadow" on its retina that darkens toward magnetic north. Just like a normal shadow, it always appears to be the same distance ahead.
Burda says that as a fox stalks a rodent, it moves forward until the shadow lines up with the sounds of its prey. When everything is aligned, the fox knows the exact location of its target, and it jumps.
Watch some incredible footage of a red fox hunting in South Dakota and see this extraordinary ability in action.
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