[paul.fr]

Not sure which board to put this in...

It has been proposed that spiders may be a good indication of a cold winter, well, not the spiders themselves, but their webs. It is proposed that when a hard winter is due, the spiders make thicker webs. Any ideas as to why this may be? Have you noticed an increase in spiders, their webs and the general thickness of them?

[dentstudent]

Paul -  I really don't think that there is any evidence of either plants or animals having the capacity to predict the oncoming seasons. There are also proposals that plants produced more berries / fruit in the face of a hard winter. This phenomena is, in my opinion, better explained by a combination of available resources to make the fruit/webs in the first place, and observer bias / confirmation.

What do you think?

[paul.fr]

Stuart, this was only proposed in passing by a professor in meteorology in the last fortnight. But there is plenty of "evidence" that animals do or can somehow know what the weather will be like. In the southern US the height of hornets nests is used to predict weather (many longtime meteorologists believe this).
Thee are plenty of folklore that do have truth in them also.

when a cow tries to scratch its ear,
it means a shower is very near.
when it clumps its side with its tail,
look out for thunder, lightning and hail.

and sheep, in a long cold winter pregnant sheep will keep hold of their young and pregnancy times will increase. when the rains come, and hence higher temperatures, lambing starts!
Im not usually one for old wives tales, but some do seem to ring true.

[dentstudent]

and sheep, in a long cold winter pregnant sheep will keep hold of their young and pregnancy times will increase. when the rains come, and hence higher temperatures, lambing starts!
Im not usually one for old wives tales, but some do seem to ring true.

Hi Paul

This last part is not, I don't think, about prediction, but based on current weather conditions. I'm sure that the pregnancy period can fluctuate in accordance with the duration of cold weather, and that favourable conditions promote birthing. But I do not believe that this is due to "prediction" - rather a response to recent events. We also see this "predictive" effect with many marine creatures spawning when conditions are of a certain type, conducive to improved success - an evolutionary artefact (though there are some I'm sure that would say it was designed...)

The old "red sky at night" tale can seemingly hold true, but this is also in response to observer bias.

As I work closely with trees and tree rings, we know that we can reconstruct previous climates and weather. However, there is not as yet, and at least in my field, a mechanism for predicting oncoming climate/weather from trees. Of course, this does not necessarily mean anything for spiders, but I would just bring into question the concept of apparent prediction as seen from the human point of view.

[dentstudent]

http://www.statesman.com/news/content/news/stories/nation/09/21/0921almanacs.html [Links inactive - To make links active and clickable, login or click here to register]

This is something that I found - and to me it appears to be very similar to cold-reading, the system used by apparent mind-readers where the "hits" of the prediction have a high probability of being correct. But how often have we reconsidered these predictions post-event? I would say, not often. And those who make the predictions are not likely to raise the issue if they were wrong. You will however, hear about it if they were "right", and so we only hear about the "hits" and not the misses, and hence we get bias.

[paul.fr]

Hi Paul

This last part is not, I don't think, about prediction, but based on current weather conditions. I'm sure that the pregnancy period can fluctuate in accordance with the duration of cold weather, and that favourable conditions promote birthing. But I do not believe that this is due to "prediction" - rather a response to recent events....

Ahhh, yes, more than likely you are correct with that one. I am always happy to be proven wrong, hence my always happy nature! I could list further instances where "creatures" are quite good predictors, but this may just bore everyone, and im strapped for time until midweek.

But i do like the spider one, there are a few folklore and observed behaviours already with spiders:

when the forecast is for hot and dry weather, spiders spin long webs. when its forecast cold, they have shorter webs.
some people have claimed that they have seem spiders break their own webs before and during Strong winds! Am I sounding like a loony? Time to go....

[Don_1]

I'm not so sure that this is all old wives tales.

I don't know about spider webs being thicker when poor weather is on it's way, but I do wonder if animals can sense changes in humidity and pressure in a way that, maybe, we once could, but have now lost the ability. Perhaps they can even smell atmospheric changes.

It would make sense for a spider to have some idea of the coming weather conditions. Making a web stronger and/or more flexible in high winds would have real advantages. I wouldn't be surprised if they do have some degree of forecasting ability.

Probably better than our satelites and watching cows in a field.

Red sky at night
Shepherds delight.
Red sky in the morning.
Barn's on fire!

[dentstudent]

I think that what needs to be defined is the "prediction" period. I would be very happy to accept the premise that spiders may somehow be able to be receptive to changes in atmoshperic pressure, and as a result build thicker webs, in the same way that dogs can "predict" thunderstorms or other animals, earthquakes. So, over say a 6 to 12 hour period, then I think that this may hold. However, to use spiders or anything else as a predictor of long-range forecasts is without scientific foundation. Of course, I'm open to new information though!

[paul.fr]

I think that what needs to be defined is the "prediction" period. I would be very happy to accept the premise that spiders may somehow be able to be receptive to changes in atmoshperic pressure, and as a result build thicker webs, in the same way that dogs can "predict" thunderstorms or other animals, earthquakes. So, over say a 6 to 12 hour period, then I think that this may hold. However, to use spiders or anything else as a predictor of long-range forecasts is without scientific foundation. Of course, I'm open to new information though!

Good point, and why my example with sheep does not work.