get this book:

http://www.amazon.com/Biology-Spiders-2 … 749&sr=1-2

I get strange urges from time to time where I feel compelled to understand something. If I don't understand spiders, then that would be bad. I don't want it to be bad, so I must understand them. Anyway, the author assumes the reader is very familiar with anatomical terminology (which this reader is not), so I have to keep a dictionary nearby while reading. What's interesting about spiders is that their CNS (central nervous system) is enormous. It's so big that the esophagus passes through it. Also, they don't breathe through their mouths, but through slits or holes located ventrally (bottom) on the opisthosoma (abdomen). Among many other interesting things, the author also explains how spiders are able to walk upside down on smooth glass.

Spiders are freakin' awesome, but they're also scary as shit. The most I know about them I learned by watching the "Planet Earth" DVD set.

So ... how ARE spiders able to walk upside down on smooth glass?

Also, I'd personally appreciate you using this thread to post interesting things you learned from the book. There's no way I'd get around to reading (or BUYING) said book, but I am interested fo sho!

maybe when i am done with med school.
for now, i am mad with the human body.

Forgive me for what may sound like a stupid question, but what does the size of an organism's nervous system dictate? I guess it controls behaviour in some way, but for a spider to have a proportionately large CNS would suggest something is altered, at least in some small way? I wonder if it is related in some way to instinctual behaviour . . .

That pretty much sums up my opinion. Interesting but friggin' shit scary. I never kill them though, then again, we don't get Tarantulas in the UK............. *Ephidel thinks of Global Warming* YET OH SHIT!!!!

Correction: not all spiders can grip glass.

   It's primarily the wanderers, such as wolf spiders and jumping spiders. They have dense tufts of hair, called scopulae, directly under their tarsal claws. With those hairs, they are able to achieve about 160,000 contact points. Quote:

  "The commonly held belief that the scopulae function like suction cups is erroneous. Electrostatic forces are not involved either. The spider's surefooted grip is achieved merely by the forces of physical adhesion. Adhesion is enhanced by the capillary forces of an extremely thin water film on the substrate. If the water film is absent, as in Teflon foil, then even scopulae-equipped spiders begin to slide or fall off, although normally they can easily walk upside down on glass plates."

  Another quote:

  "One problem that is not quite resolved is how such a grip is loosened again. It has been suggested that a spider can, by degrees, detach its scopula hairs hydraulically by gradually increasing the hemolymph pressure."

   Hemolymph was one of the words I had to look up. It's the equivalent of blood in spiders.

  When I get some more time, I'll tell you about spider venom.