[Michael Hendry]

Michael Hendry  asked the Naked Scientists:
When you see small rodents crossing a country road, they invariably cross at right angles to the edge of the road.

Bearing in mind that their eyes are probably only 2cms above the surface of the road at the maximum, whilst the camber of the road may mean the centre of the road is possibly 25cms higher than the road is at the edges, how do these small rodents work out the correct angle to cross at, even assuming of course that their vision allows them to see as far as the other side?
   
Love your website - I shall persuade my 15 year old son to look at it.
   
Michael Hendry
What do you think?

[DoctorBeaver]

That's the sort of silly question I ask  []

[turnipsock]

I'm sure this is something for the Darwinists. I guess the ones that set off at eighty nine degrees have a higher chance of getting squished so will be removed from the gene pool.

[rosalind dna]

I live on a busy London road and yet we have a fox that crosses the road blase of everything else around it, cars, people and
I've even seen the fox check which way the traffic is coming from.
Honestly and it's a right pest too.

[DoctorBeaver]

I live on a busy London road and yet we have a fox that crosses the road blase of everything else around it, cars, people and
I've even seen the fox check which way the traffic is coming from.
Honestly and it's a right pest too.

See my post http://www.thenakedscientists.com/forum/index.php?topic=13130.0

[turnipsock]

I live on a busy London road and yet we have a fox that crosses the road blase of everything else around it, cars, people and
I've even seen the fox check which way the traffic is coming from.
Honestly and it's a right pest too.

See my post http://www.thenakedscientists.com/forum/index.php?topic=13130.0

I nearly posted on Doc's thread. There are a lot of foxes around Bearsden, nr Glasgow, that check the traffic before crossing. They are around in the middle of the night.

When the BBC did that turban watch tuhing, the foxes from Glasgow were featured!

[SquarishTriangle]

In many situations, if there is an easy option to be taken, it will be taken.

Firstly, if you’ve ever tried to walk up a hill on an angle, you will have realised how awkward it is. Not only is your gait forced to become asymmetrical (one leg is higher on the slope than the other), but the joints in the leg (apart from the hip) are really not designed to bend sideways to adapt to the slope of the hill. So from that perspective, it could be that the mice are just choosing to cross the road in the way that is most comfortable. Secondly, to get from point A to point B, you tend to go for the shortest route possible. Assuming that the mouse can’t actually see the other side of the road over the ‘hill’, it should still be able to see a line formed highest part of the road, and that line will be roughly parallel to both sides of the road. The route of shortest distance to that line would still be at a right angle to where the mouse is standing. However due to the position of their eyes, mice have somewhat less ability for binocular vision and depth perception compared with us, so I’m not sure how well they would be able to judge distance over that sort of scale.

Lastly, there’s probably an element of learning and practise involved. I would imagine the mouse is fairly familiar with its foraging territory, which happens to include the road, and actually crosses the road relatively frequently. If that’s so, with experience the mouse will have worked out how to best cross the road and do it as quickly as possible.

[JimBob]

This seems a very reasonable response to the question. The logic is impeccable.

[SquarishTriangle]

Why thank you Jim.

[JimBob]

It is my pleasure, madame.