If you lower human life to the level of a mere animal, then you have to have a very low opinion of your peers. If somebody you do not know dies you would treat this with the same indifference of somebody stepping on a bug. Seeing a small child get mowed down by a car would be no different to you than seeing a dead cat on the side of the road. The picture Sean posted of the cat would have the same affect on you as that of a picture of a bleeding human corps.
My guess is that neither of these is the case, if they were I don't see how you could function in society. I imagine you have some middle ground you have compromised on. I still think you would have a difficult time fitting in with society.
Okay, the difference between animal and human life: Can a mouse build a mousetrap? No. It uses its instincts. It is all instincts. The cat will use the same methods over and over and over again while trying to catch a mouse. Cats don't display emotion. If two cats live in the same home for many years and one dies, the other will hardly even notice it. Its corps could be in the same room for a number of days and the cat would react to it with indifference. Put the same situation with two humans, and the experience would be tramatizing. Having your friend or roommate die, then being in the same room with his body for a few days. When the mother of your dog dies, your dog doesn't even really care. If they were close, then maybe he will whine for a day or two and look sad. But he will be over it in a week. A human looses his mother, it can take a year before he gets back on a solid track in life, and he could very well live the rest of his life without getting over the trauma. These are some very minor examples of the differences between humans and animals. This could go on for ever and in much more detail. There is a very distinct difference. Do animals love? Do they cry? Do they communicate anywhere near the level humans are capable of communicating on? Can they think for themselves? Can they plan, design, and build? Can they dream? Can they hope? Can they be inspired? Can they draw? Can they write books? When a pack of animals is being chased by a lion and one gets caught, do the others stop and risk their lives to help it? Humans do. Why? Can you seriously not see the distinction?
EDIT: Yeah, I agree Rob. He very well be taking the piss. At least I hope so.