OK, you didn't watch closely, if you look, the zombies close to where they dropped the dog were focusing on the humans, but when the dog gets close to the Gun Store, the lady zombie lunges at him. They just want the humans more than the dog, zombies will eat any living thing.
Dogs are just harder to catch have you tried catching a run away dog it is difficult. zombies eat what they can catch and in the movie she does lunge at the dog if she would have caught it she might have ate it. I want to know how sarah polley got across all the broken glass in the beginning with bare feet.
I'm not sure I understand by what you mean with "the primitive lizard" part of the brain going? Are you saying that we, as humans, have some kind of relationship with lizards? I do agree that zombies do seem to run off of pure instinct, but I think it's less primitive and more honed by the evolution of man into something more easily aimed than just instinct...
As for the comment left above yours, I don't actually believe a zombie head can survive without it's body, the brain seems to be the center for their abilities to stay "alive" and eat, if they lose their head I would think the damage done by the spinal column being severed and the nerves there being sliced that they wouldn't be able to function... I think taking off their head is just like shooting them through it...
Thank you steven,the spinal column is part of the brain but maybe the head can still survive with out the body but why should that be a threat its just a head. Unless you are in shorts and barefoot and a retard. Although i argue with my husband because i believe what Steven said it can't live with out the body but he says it can anyway that really does not matter to me I can easily toss or kick a head in the trash, problem sloved. And the primitve lizard part of the brain tells us to eat to survive...I guess....basic instincts. But damaging other parts of the zombie can kill it. As long as he is no longer a threat to you.
Solanum, the zombie virus, turns the brain into a self sustaining organ, they dont need to eat, sleep, or breath! The zombie feeds on flesh because, in theory, it tastes good. Zombies eat until their stomach bursts. One zombie was recorded to have 200 lbs of human flesh inside it. As for the head, it can still bite and it the most toxic part of the zombie. All a zombie needs to survive, is its head. Read "The Zombie Survival Guide", it tells you all of this.
It all depend on where in the spine is it breaking. If ur gonna chop a zombies head off your goin to hit a cervical part of the spine. That should kill it. Any where lower will probably just effect the body movement.