I found this looking for something for another thread. This is Loki, I used to babysit him a lot before I moved away. He's a little live-wire (terriers are like that, especially when they're ratters) and chases everything, even if it isn't technically moving. He doesn't care about what's on TV until the subject is an animal--then he goes nuts. This is him sometime last year trying to catch monkeys off the screen on the National Geographic channel. (Click to view.)
He only ever did it with animals--not people or cars or even cartoons and CGI (it had to be live-action animals), he wasn't even fooled by pictures of babies crawling around on all fours. Just animals, and it didn't matter if they were making animal-sounds or if there was a voiceover narration or if there was a soundtrack. It was the picture he wanted. He never seemed to mind that he couldn't catch any. The eternal optimism of dogs, I guess!
When he isn't chasing animals on TV, he's usually hanging out on the backs of sofas. Even if you put him on the cushions he'll jump right back up there. Maybe he likes being at the same level as everyone else?