IMHO, if the OP was going so quickly that he could not see something the size of a dog in the road in the fog, then he was driving too fast for the prevailing conditions.
We have A LOT of deer (and moose!) around here - if I am on a road where there is likely to be deer, and conditions are such that I cannot use my high beams, I slow right down. There should be no need of sudden swerves such that there is any possibility of losing control, even in a floaty Camry. Afterall, that dog could have just as easily been a lost child, or a drunk.
'11 328! Touring - Tasman on Chestnut, 6spd manual, factory upside-down "i" option