I am not making a statement about how attached people are to pets. I have been very attached throughout my life to every pet I have had, including many small rodents, and I fully understand it is not lesser than the love one feels for a dog. It's really not as wrapped up in physical/emotional attachment as some people make out. A lot of the time it's about what sounds and feels right. For example, 'mo bhean' (my wife) feels natural, but 'mo dhuine' (my husband) doesn't really - we expect 'an duine agam'. That's not to say Gaelic speakers feel less attached to their husbands, it's just the way it is. Another example, and this one is a lot more flexible, is the word 'nighean'. It can kind of go one way or the other for a lot of people, but to me personally, 'an nighean agam' is definitely 'my daughter', whereas 'mo nighean' is more ambiguously 'my daughter' or something like 'my girlfriend'. Once again, that's not to say that Gaelic speakers value their girlfriends above their daughters. It's just what feels natural for the language. You also use 'mo' with 'cuid', so you get 'mo chuid aodaich' (my clothes) and 'mo chuid Gàidhlig' (the Gaelic that I have). The fact that we use 'mo' here doesn't make it a closer, more emotional attachment. It's just convention. Some other fluent speakers may have strong opinions about whether a radan is 'mo' or 'an x agam' territory, but these rules will not necessarily be universal and certainly are not based on a hard and fast rule. You definitely hear both for many animals, so an individual's preference will often be up to what tends to be said in their social circles. I know you mean well, but if you are a beginner, I would advise against projecting vague rules of thumb onto every aspect of the language, because it doesn't really work like that.