Lion or dog? I think he is a lion. Known as a "Shisa" he is there to protect the building. Made of some kind of metal he is very decorative, and we can see the Chinese influences again in the scrolls. They usually come in pairs at a gateway, entranceway or roof top. One on the right will have an open mouth to ward of evil spirits, while one on the left will have a closed mouth to keep in the good spirits. Interesting Okinawan mythology.