I’m willing to believe that this is true, but my real question is how do they do it?
I can imagine an animal like a deer or a bear, or even a squirrel ranging far and wide, and knowing ‘their territory’ well enough to get wherever they want to go within that range. They know the place, or travelled under their own power to a new place, so they know how to get back.
But the claim is that you can take a mouse or other small animal (I’ve also heard the same about groundhogs), put them in a box (a trap/cage), then in another box (a car or truck) drive them ‘several’ miles away, at unheard of speeds (for a mouse) and when let go, they will have a sense of what direction ‘home’ is. I don’t see how that’s possible, does my little house in the woods have such a magically unique smell that a mouse can pick it out from 3 miles away, and avoid the other couple hundred houses within that circle?
From a very brief scan of popularized science articles – animals and birds use star locations, magnetic fields, sun location, scent (including under water, like migrating salmon), visual landmarks, and other tools, including some we likely do not know anything about, to find their ways.
Dogs for example, have any number of documented incidents of traveling over a thousand miles to get back home. We only know about this capacity of dogs because they live with us.
Scent, a sense we can barely use for anything, is of enormous importance to most animals other than us. Dogs can smell molecules. The capacities of animals other than ourselves is mostly an unknown country to us.
And I don’t want to fight the hypothetical, as it were, but let’s admit that for every lost critter that finds their way home, there’s an unknowable number that don’t.
So it’s hard to gauge the effectiveness of the homing instinct because we can’t really know anything about all the times it’s ineffective.
Animal control people have a good sense of this. They have a lot of experience dealing with people trying to get rid of unwanted animals hanging around their houses. If trapping and dropping the critters off several miles away was effective in the vast majority of cases, they would know it; likewise if that’s generally futile.
We had several mice living under our house. I humanly trapped them and took them to a park a couple of blocks away (not miles). That was 6 months ago. None of them has made it back yet.
Also keep in mind that all mice look the same to us. How could you tell the difference between “I trapped one mouse, took it far away, and that same mouse came back”, and “I had a bunch of mice, but only found one, took it far away, and then found another one of my many mice”?
True. I once lived on a dead-end road 12 miles from the nearest town. A depressing number of people would dump their dogs nearby. As our dog did not take kindly to canine housemates, we were frequent flyers at the Humane Society. I was glad the dogs couldn’t find their way back to such idiotic, cruel owners. Hopefully all the pups found happier homes.
True. On the other hand, a mouse making it back to your house after being taken a few kilometres away is trivial compared to something like the godwit.
Maybe it’s not the same mouse, but if it is the same mouse, it’s not out-of-this-world amazing or anything.
I remember as a kid reading a “New of the World” article in Mad Magazine telling of a family from Seattle on a road trip losing their dog at a rest stop in Kansas. “Six months later it showed up on Orlando, still walking the wrong way.”
Astoundingly, it seems the evidence it did is pretty sound. The birds carry a tiny tracker, and the track is pretty unambiguous. This article from the Guardian is about the best I could easily find. There are a lot of sites quoting one another delivering the same news.
Well it’s not just one bird. The godwits make an annual migration between Alaska and New Zealand. It happens that 4BBRW has recorded the longest flight, but they all do long flights.
A friend of mine kept trapping a mouse that looked like the same mouse. He’d release it quite some distance out into the woods and it kept coming back. To see if it really was the same mouse, he put a dot of his wife’s nail polish on the mouse’s forehead. When the mouse got trapped again, it had the dot on its forehead.
He then took the mouse about 20 miles away and released it. It never came back.