Dogs often feel like members of the family, but it is hard to know exactly what a dog is thinking or feeling since they can't talk. 

Dogs also have a limited amount of facial expressions so the only things we really have to go on our their body language and tails. 

This SciShow video talks about how the way dogs wag their tails can show us and other dogs what they might be thinking. 

Check out the video and then leave me a comment and let me know if have picked up on your dogs' body or tail language.