Tuesday, November 25, 2008

Spider dreams

This morning when I stepped outside I noticed the spider that was silhouetted against the pale morning sky, hanging between the honeysuckle and the power line where it has been for the past couple of weeks. It is a large spider, and its web is enormous. The web is getting a bit messy with bits of leaf and other rubbish stuck in it, and I wondered if spiders ever did housework.

The spider did not move. I have never seen it move, and I wondered if it was awake yet. Then I wondered if spiders actually sleep. Do they close their eyes? Do they even have eyelids? Do they dream? And if they dream, do they dream in colour, or in black and white? What do they dream about? Do they ever have nightmares? What are their nightmares about? Brooms?

I have to go to work now, so I'll leave my readers to answer these questions for me.

11 comments:

kenju said...

I don't really know, but I imagine that they can sleep, since any bug that got into the web would make it move and the spider would wake up and get the intruder.

Keera Ann Fox said...

If a spider has nightmares, I hope it is of me, hanging above it, ready to drop down on its face just because. That would be nice revenge.

If a spider has dreams, I hope it is of me, grabbing an empty milk carton to scoop the spider up with and releasing it outdoors, back into freedom.

Most nerve-wracking question asked me regarding spiders: Do they scream when you step on them? I actually still wonder about that one.

Dr Curley said...

Welll... digging around in Wikiped, the spiders that best answer some of BA's questions are jumping spiders (http://en.wikipedia.org/wiki/Jumping_spider).

Spiders in general have about 8 eyes, with about a 1/5 of our ability to focus - this is much better than insect focus for instance. Jumping spiders have color vision, extending into the UV range. But they certainly don't have eyelids.

Spiders have big brains. Neural material is what fills much of what we would call the 'head' of a spider. Unlike that of most insects, spider behavior changes quickly with the environment, I guess that's true of our other main Arachnid, the scorpion, also.

Putting these things together: my guess as an amateur neuro-scientist is that while spiders don't sleep, they dream. If we get real close to a jumping spider's main eyes, and move a little until its eyes seem darkest, we're seeing its retina: spider is looking right at us. What would a spider dream of? I'd guess if it can see us, it will dream of... us! :-)

Badaunt said...

Kenju: Maybe, since they don't have eyelids (according to Dr Curley) they ...doze? The light must get a bit annoying, though.

(Which leads to a new question: Do spiders get grumpy?)

Keera: I think they probably scream JUST OUTSIDE your range of hearing. (Did you ever read the Roald Dahl short story about screaming vegetables?)

Dr Curley: Big-brained daydreaming spiders ... you have given me something new to think about every morning when I look at that spider still hanging out there between the honeysuckle and the power line.

I know that some spiders react quickly to me, at least. Those big house spiders react so quickly they practically give me a heart attack every time they react. Do I count as 'environment'?

Don said...

Some spiders have soft and soothing voices, and can make a scared little pig very famous.

Contamination said...

Spiders have nightmares about Garfield.

Dr Curley said...

"Do I count as 'environment'?"

A traditional Japanese house certainly does - with its rendered walls, wooden ceiling and tatami floor, it's indoor spider paradise. But humans are something else again...

A spider's main predators are birds and parasitic wasps - spiders are a 'keystone' predator themselves (small biomass, large impact on ecosystems) but they do have real enemies above them. And above those: us! we're the super-predator, the Eradicator!

It does seem sometimes that most of what we know about anything except our speciality is largely myths our grandmother passed on to us. Spider aggression toward us is flight & fight, they've no desire to tackle us. Some spiders are vegetarians; some spiders are social, living in large colonies; nor are all male spiders eaten after mating. In fact spider sex sounds amazing: it's pretty much all cunnilingus - not that I'd want to be a spider! :-)

Keera Ann Fox said...

Badaunt, considering that I am mostly vegetarian, I think that's one Roald Dahl story I'd better avoid. :-)

Don, that is one movie I want to see. :-)

BTW, I just read that spiders in space can figure out how to make proper webs, in spite of zero gravity.

Anonymous said...

I dion't know about dreaming, but spiders can definitely learn! I once knew a girl who trained an ordinary spider to eat out of her hand. She used to give it flies she had caught. As a result, the spider was not afraid of people at all, and you could allow it to walk on your arm without having to fear ts bite. She kept it in her kitchen, where it had a huge web above the fridge. I personally consider her parents to be the most tolerant people on the face of this planet! I guess the kitchen and the girl with dead flies fell under the changing environment... Yes, we were strange as children...

Contamination said...

Any update on what you think spiders dream about?

Badaunt said...

Contamination: If Dr Curley is right about what they see, then they probably have nightmares about something like this.