Re the deer eating flesh. We have a huge deer problem here, they are everywhere and on garbage day you will see scattered garbage and the deer going thru the trash - they will eat meat if they find it I saw one once munching on a turkey carcass it had found in the garbage. Further to deer not being strict vegetarians, I once read an article on bird banding. Scientists would set up nets in the forest and capture birds to band and count them and then let them go. They were puzzled to find that there were very few birds in their nets and surmised that something might be taking them. After setting up a camera they discovered the culprits - deer, who were apparently delighted to have such an easy source of protein.
As for the bear and dogs. They do have a common ancestor but in general they don't get along. We had a dog that hated them and as soon as he saw one, he'd chase it up a tree. This was not something we encouraged but he would know if there was one in the area before we would be aware.
As for the photo of the polar bear and sled dogs. Polar bears will eat ANYTHING and they will kill and eat dogs if they catch them. The scientist who watched that encounter believed that the bear was not hungry and that it was young enough to still be playful which saved that dog's life.