I’m not a big fan of d*gs, but I make an exception when it comes to foxes. They’re cute (almost catlike), furry, have magnificent tails, and are smart and wily. This video from Discovery, showing foxes hunting rodents under several feet of snow, shows their remarkable hearing. It’s unbelievable that they can feed themselves this way, but the narrator says they succeed 75% of the time. Watch its ears twitching as it homes in—like mammalian radar.
The YouTube description below implies they use the magnetic field, but I have no idea how that would work. The explanation in the video is obscure.
A red fox pinpoints field mice buried deep beneath the snow, using his sensitive hearing and the magnetic field of the North Pole to plot his trajectory. For more North America, visit http://dsc.discovery.com/tv-shows/nor…
h/t: Su
Tom Selleck narrator.
Rather sloppy that the narrator doesn’t make it clear when/if he’s talking about the geographic or about the magnetic north pole. 3000 km makes quite a difference.
How could it be anything but the magnetic North pole?
They have chronometers and an astronomical ephemeris?
I have no idea why they would be aided by the earth magnetic field. Maybe it is not so much the fox but the mice that are using the magnetic field. Perhaps mice tend to run their tunnels N/S, so the fox is more likely to intercept them when diving in along that direction. Or the whole thing could be total nonsense.
I initially read the title as if there were rodents that hunt foxes! My first thought was “How big are these damn rodents??” My bad. 😀
That would be “fox-hunting rodents”. Punctuation makes a difference. For example, don’t write “Let’s eat Grandma” when you mean “Let’s eat, Grandma”.
Oh, I completely agree. I recognised where I went wrong. But I guess it was down to being a Brit and not paying due attention. When I see the words ‘fox’ and ‘hunting’ it’s normally in the form of fox-hunting (not sure where you’re from, but for clarity, fox-hunting, although currently banned, is a popular past time with posh people).
How about scent? Foxes are very good at sniffing out prey like voles and mice. Magnetic pole? Who are these people?
How would scent help through many feet of snow? It might alert the fox to the fact that there were rodents somewhere in the vicinity, but far too diffuse for ‘targeting’. I think the fox must do it by aural means (and the ‘north’ correlation may be just that the mice build their tunnels in a north-south direction).
I should have mentioned that voles create tunnels (veritable labyrinths) through the grass and cut grass stems into pieces approximately two inches long. This makes noise (to which the fox is listening when it turns its head), The voles also create softball sized “rooms” of grass stems to live in under the snow and these would smell pretty voley I would imagine.
I have heard that foxes don’t eat voles, or anyway no further ones after the first experience.
I didn’t listen to the narration & just looked at the video since I was on the phone at the same time (yes, I multi task too often).
The fox is cute especially when he/she listened for the mice. I can’t help but think that snow is cold on the face, even with fur!
From my experience, foxes are very smart (I guess clever like a fox) and very curious. There was one here in my driveway that stared at cows in the next field for hours (cows, being cows, crowded around all pushing & shoving to look back at the fox).
This is a good explanation of how the magnetic rangefinding works.
Don’t all the other animals given in the examples use their abilities for navigation where precision of 200 metres or so are probably adequate? The implication here is that the fox is able to detect variations in the earth’s magnetic field that gives it the ability to position itself with millimetre accuracy.
Is there any other animal that operates so precisely?
Bacteria? 🙂
I don’t think the as much precision is required as you may be thinking.
It’s still just a directional reference. The claimed novelty is that it’s the direction of the magnetic dip (which gives a vertical reference angle).
http://en.wikipedia.org/wiki/Magnetic_dip
The hypothesis is, the fox can sense that angle and match it consistently, allowing it to practice leaps onto sound sources coming from that angle and get very good at them.
So, the fox isn’t measuring a relative value and making precise corrections, it’s sensing a fixed “sweet spot” and returning to that again and again. Also there’s much less variation in the magnetic field over a fox’s hunting territory than over a 2,000 mile migration.
It’s an interesting idea, but of course this is still just a hypothesis. Here’s the relevant explanation again:
“This targeting system works because the Earth’s magnetic field tilts downward in the northern hemisphere, at an angle of 60-70 degrees below the horizontal. As the fox creeps forward, it listens for the sound of a mouse. It’s searching for that sweet spot where the angle of the sound hitting its ears matches the slope of the Earth’s magnetic field. At that spot, the fox knows that it’s a fixed distance away from its prey, and it knows exactly how far to jump to land upon it.
“Philips explains it very well. He says, “Imagine you had a flashlight attached to your belt that was pointed down at the ground at a fixed angle of say 60 degrees. The beam of the flashlight would hit the ground at a fixed distance in front of you. If you were trying to determine the exact location of a sound source coming from the ground in front, you could approach until the beam was exactly superimposed on the sound source. This would place you at a fixed distance from the source. As you attacked such targets again and again, you could perfect a highly stereotyped leap that precisely lands you accurately on the target.” “
That, however, depends on you holding the flashlight a fixed height above the ground. The depth of snow is variable, so I don’t think the flashlight comparison works well. I also see that the most successful direction for the Czech foxes is 20 degrees to the right of magnetic north – and if they reverse that (meaning pouncing to the south west, presumably), they’re almost as successful – dropping from 73% to 60%, compared to 18% in other directions. That indicates there’s more to it than ‘align with the magnetic field’.
I’d like to see how they analysed the direction of slope (north facing and south facing snow can have quite different characteristics) and the prevailing wind, which can again affect the consistency of snow. It may just be that there are slopes it’s easier to break through to the required depth, and the foxes can judge them better when facing uphill or downhill, rather than transversely.
So it is magnetic cow, deer and fox now? And all claimed by one group of scientists.
… okay … [/backs slowly away] Nice fit to pseudoscience all over again. Not that it needs to be of course. But I wonder why Ed Yong and the others were taken by such a precarious claim?
Ah, I thought I remembered the cows: later in 2011, a group failed to replicate that first study.
“Sönke Johnsen, who studies magneto-reception at Duke University in Durham, North Carolina, says that at least some of the images in question should probably not have been analysed. He also suggests that the proper unit of evaluation is probably the herd, as the alignment of individual cows in herds is unlikely to be independent. Overall, he says that the original results, “while mysterious, still stand”.
Jelinek says that his team does not intend to pursue any more research on this topic. Meanwhile, Burda’s team is already looking at magneto-reception in other animals.”
[ http://www.nature.com/news/the-mystery-of-the-magnetic-cows-1.9350 ]
Seeing the disagreement and how the lone group pursued it, albeit with outside support (which I don’t get – now the *herd* is supposedly magnetic !?*), I thought that cow was of a standing of out of alignment for good. =D
* Is that selection bias applied on group selection claims? Reminds me as of how two wrongs seldom makes a right.
I’m not a big fan of c*ts, but I make an exception when it comes to tigers. They’re cute (almost catlike), furry, have magnificent tails, and are smart and wily.
Gray foxes travel through my yard fairly often. After one winter snowfall my wife and I were extremely fortunate to see this behavior. The animal was unsuccessful but we were awed nevertheless.
And then there’s Bailey, who has someone feeding him and so can plow the snow for fun. (Mute audio!)
Love Bailey!! ( though don’t know why so many people name their dogs Bailey…)
How about S American grey foxes? If they have similar skills, do they orient N or S for success?
I’m a cat person but I like dogs too (not enough to have one, though). However, I particularly love and admire wolves – their intelligence, their social structure, the way they cooperate when hunting, the way the whole pack looks after the young (only the alpha male and alpha female will reproduce), the way they regulate the births according to how much food/game is available. Plus, they are very beautiful animals.
Living With Wolves
Like you, I see no point in choosing between dogs and cats: I have two dogs and a cat. They are both amazing animals in different ways.
As for wolves, I live in Canada which has the largest wolf population in the world. In the past few years we have seen populations of wolves moving further and further south. Here in the Thompson/Okanagan region of British Columbia (a few hours north of Vancouver) we are starting to see wolf attacks on livestock and dogs—something I never thought I’d see. Of course, the ranchers hate them, but there’s no denying that they are an extremely successful and adaptable species if given half a chance. You’ve got to admire them. I hope our government doesn’t declare open season on them.
What does the fox say?
“nom nom nom nom-nom-da-nom nom nom”
Hey, has anyone tried to watch this North America series. I am a fan of these kind of shows, for example Planet Earth, Wild Russia, Wild China, and the North America thing is similar.
But they do at least two very annoying things, that I am cognizant of. They obviously are trying to make it more of an entertainment show. First, they will break into these songs (singing) with some kind of theme, some love song for a mating montage. Secondly, the voice over is plying this kind of macho, American (U.S. American) kind of ideal, with portraying the animals as individualistic, rugged, cowboy-like, in an unnecessary way. Portraying nature to American audiences as if the animals here (unlike elsewhere) fit perfectly into the quintessential “American” mold.
Anyways, like other shows they have very cool animal pictures and some analysis but they then go and do that.
I agree 100%. Fixing the animals up with a USian agenda is grating. Too bad it’s the “American” way, must mold and capitalize everything. One greed to rule them all.
My dog does the same thing, learned it from his Mum.
The mice create regular trackways beneath the snow and he makes his rounds every morning to scoop one or two.
After he grabs one he snaps it’s back with a shake of his head, tosses it into the air and swallows it whole on the catch.
No compass, though, and he sure didn’t learn trig from me.
My B*rder C*llie does the same thing. Don’t know about the north thing. Sounds dubious.
About 60 years ago I had a pet fox (named “Rommel” no less) and he use to do leaps like that on the back lawn. Chasing grasshoppers or crickets? Or just going through an instinctual behavior?
Surely it has nothing to do with the madnetic field. Unless they show why its just speculation because they don’t think the foxes senses are good enough to find their prey.
This YEC creationist sees foxes, wolves, bears, probably seal as just of the same kind from pairs etc off the ark.
They are creatures of the nose. The fox most likely, as posters here said, smells the creatures/homes first and then uses its hearing to pinpoint them.
No compass or GPS need be invoked.
The funny thing is, that the two times the video actually show the fox catching anything, is when he is facing in a southwards direction. (he is facing southwards because the shadows are behind him)
Blacktip Reef Fox (I know, you’d think Hammerhead, right?, but check out the ears): The Vulpes’ Ampullae de Lorenzini, not being in saltwater, Electroreception depends on the whiskers functioning as ‘antennae’ of sorts, tho with the Lateral Line extending all the way to the tip of that furry tail, OF COURSE you’re gonna have to line up w/ Magnetic North!… I mean, duh!…
I would assume that it is north hemisphere, therefore if you face south – pretty bright sun and it’s reflection from the snow blinds you and mess up your targeting.
Occam’s razor…..
Another possibility not mentioned anywhere is that the voles’ snow tunnels are consistently oriented with respect to the Earth’s magnetic field. I studied meadow voles (Microtus pennsylvanicus) for several years and noticed that their trails seem non-randomly arranged (many are parallel tracks in the meadow grass). A possibility to explore is that in the winter the voles use the Earth’s magnetic field to align their tunnels under the snow (being unable to use any other cues)and that this is the explanation for the foxes’ success when using the same alignment (north and south).
Just speculating but, how about the prevailing wind is from the north when the snow is laid down so maybe making digging by the rodents easier along a north south line. Or if the wind has blown the grasses so that they lay in a north south orientation the rodents orient their tunnels in that direction in order to work with the grass more easily. The fox at any rate would likely have a greater margin for error if it was oriented along the tunnels then when oriented across the tunnels.