I see those as two basically different phenomena: 1. Is X capable of feeling pain / sentient? 2. Is X capable of having emotions? It seems probable that (1)

I see those as two basically different phenomena: 1. Is X capable of feeling pain / sentient? 2. Is X capable of having emotions? It seems probable that (1) is a precondition of (2), such that we should not be surprised if there are sentient creatures (perhaps including dogs) that are capable of feeling pain, are intelligent, and able to produce apparently emotional displays without having evolved the underlying experience of emotion. Human emotions are complex and came about as the result of a long period of evolution with an intricate social system built on top of it. The emotions that e.g. dogs show are the result of a few-thousand year history of humans selectively rewarding a particular animal for displaying a certain behavior. It is, IMO, beyond the pale to suggest that animals like dogs don't experience pain or have subjective experience. (And the same goes for pigs, cows, and most other vertebrates.) That would come as a surprise to some rather intelligent historical figures like Descartes. I don't think it's similarly strange to think that these animals don't experience emotions in quite the same way we do, or that an apparent display of "sorrow" doesn't map 1:1 to an internal experience of sorrow in the way we might expect.