That's frustrating, I guess people might think since it's their dog they have all rights?

Someone from Canada wrote the following...is this true and if so is it also true in the US? She is saying that since she was hired to take the photos, the client owns the rights to use them:

Don’t know how it is in the US, but in Canada it is definitely work for hire and the default position is that copyright goes to the person paying for the job unless stated otherwise.