Learn English – Referring to objects as “she”

In the 'Have you seen those boots?' example, if meant as an exclamation, there is also a sense of distancing oneself. That is to say if it was meant to imply "Have you seen those boots, they are fantastic/awful", one is indicating the boots are not yours, but belonging to someone else, and thus conceptually distant from you.

If the question is taken to mean "Where are the boots?" then their distance is unknown, and thus also conceptually distant.

In summary, I would use 'those' when something is either physically or conceptually distant, and 'these' when they are near to me, either in proximity, or my emotional sentiment toward them. That's the best way I can frame it logically, anyway.

No rules beyond the rule of personal preference. Some folks like to indicate whether the person or animal is male or female. Why? Because humans are curious about such things. How many normal human beings wouldn't ask about a newborn dressed in yellow or green Is it a boy or a girl? Only the hopelessly PC who think that it's somehow unfair to burden a fellow human with a sex label that fits. After all, it might be a hermaphrodite, and that question just might embarrass the parents.

Animals that are obviously male or female (you can tell when it's dog or a horse, but not necessarily when it's a snake or a sparrow) can safely be referred to as he or she, but there will be purists out there who'll insist that they're properly referred to as it. That Grammar God speaks to a lot of false prophets, however. Maybe it's the Grammar Devil?

I don't know why anyone would want to grace a frog or any other similarly slimy life-form with he or she. Only animals that you can make friends with deserve that kind of preferential (I'm not a lover of PC) language. If, however, you're a frogologist, then you'd care a lot about whether the frog was a male or female, at least in some cases. So why not use he/she? There's no grammar rule against it, only people's personal judgments about what's right and wrong (absurd,I think) in such cases. Personally, I make my own judgments about this kind of small stuff and don't judge others when they make different judgments. It usually doesn't matter -- except when people say "He's pregnant". Then I wonder what's going on.