They have senses just like us and even have souls, when we are dead we could come back as an animal. My plastic will kill dolphins and then I am a murderer. It's true, I saw it in a documentary at school. They got this plastic bag out of a whale. But it could have been a dolphin.
Bags get to the ocean by strangling cows.
Whales and dolphins have bigger brains than us and are therefore more intelligent. It might seem a bit confused, but life is confusing. As they get older the effects of all the public health messages on some peoples subconscious could build up. They might worry excessively about having a heart attack because of eating fat or even of being fat. That is if they can get their mind off cigarettes and their chances of getting cancer.