Toady your message makes complete sense now. If they go insane from an inability to reach the chasm, then that is it.
The location that they go insane is in my Coin Castle. This is a section of my fort locked behind several doors, with just a sole dwarf living in it. I use an airlock system to transfer food / alcohol / metal into the Coin Castle, and I gave him a legendary bedroom, statue garden, and dining hall all for himself. Then he has his magma forge for minting coins, and a massive vault to store them. Included in all this is a single well in case I forget to restock his alcohol.
So all the ants that pop out of there are unable to reach the chasm, since they are locked behind a few doors. Therefor, according to your explanation, they go insane. Mystery solved.
Edit: Coins are kept separate from all other dwarves so that I can run an economy without dwarves spending all their time hauling coins around and splitting my 500stacks into 500 1stacks. They occasionally complain about not being able to reach their coins, but nothing bad ever happens. Strangely, the coins still split up when claimed, but they all remain in the same tile. So my 1 tile with 1 stack of 500 coins typically becomes 1 tile with lots and lots of smaller stacks of coins, without any dwarf touching them. Credit based dwarven society!
[ September 02, 2007: Message edited by: Ravendas ]
[ September 02, 2007: Message edited by: Ravendas ]