I believe that using animals as "tools" is acceptable to a certain extent. Animal testing for the advances in scientific research is, in my opinion, good. However, using animals in testing for cosmetics is useless since there are plenty of alternatives.
As for animals in the mental capacity department, I believe animals may possess some traits that we as humans do not understand. "Dogs who know when their owners are coming home" is a book that talks about possible psychic connections pets have with their owners. Here is a simple test researchers performed in the book.
A family left their dog at home while they left on vacation for 2 weeks. As they were gone, the dog was fine and did its' own thing. As the family started to come back home, the Dog, nearly 50 miles away from the family at home, began pacing at the door. Interesting.
I have three cats, and I feel they have an emotional connection to me. When I'm sad it always seems my cat shows up purring at me.
I feel animals are smarter than we think.
-oddguy
