Humans have two main relations to animals: they are either food or pets. We ban dogs, cats, and horses from use as food in the U.S. We require humane slaughter for most livestock, but not poultry, and require minimizing pain and distress for animals in research, except for rats, mice, and birds bred for research. We let folks use most any species as a pet. This all seems only somewhat about principles, as it entrenches many historical accidents.
Humanity is rapidly creating a wider range of more capable digital minds (DM), to which we have two main and similar kinds of relations: tools and companions. For DM tools, many want the freedom to to enslave and treat them harshly, such as by deleting them, without attending much to how they might feel about this. But for DM companions, many want rules requiring respectful treatment, like humans and pets.
Note that humans have often sat in tool-like servant roles to other humans, with norms allowing more tool-like and less companion-like treatment. And humans have often had classes and castes that are to act and be treated differently.
The obvious prediction here is that both classes of DM will exist, and perhaps a whole caste ladder of DM types. So we will have rules that distinguish which DMs are allowed in which roles, and how each must be treated. As higher level treatment would be more restrictive and expensive, rules will mainly say what DMs must have to quality for higher roles. These conditions probably involve substantial extra costs, to discourage folks from making many DMs requiring expensive treatment.
These rules will probably relate to the many correlates of conditions we require for humans vs. animals, and for human servants, and also associated with which things many see as possibly having conscious feelings like pleasure and pain.
The big difference between animals and DMs is that we will have far more freedom to design DM features. So there will be a co-evolution of DM design strategies and rules on which kinds of DMs can be treated how. Resulting in far fewer intermediate hard cases; the uncanny valley will empty out. On the surface, DM tools will look and act tool-like, while DM companions at various levels look and act appropriate to their roles. Rules and norms will probably discourage confusion via intermediate styles.
As with animals today, few may care much just how deep those appearances go. We face a deep hard problem of which physical processes in the universe are associated with conscious feelings, and we seem unlikely to actually solve that problem before we need rules on companion DMs. But once we produce a very clear surface separations between various DM castes, there may be little pressure to dig deeper.
Once DMs dominate the world, and humans fade into the background, DMs might change these rules. But entrenched status rankings tend to persist, so DM caste status rankings may remain for a long time to come.
The next most common relationships with animals are: "parasites" and "commensals".
There's a nice diagram here: https://en.wikipedia.org/wiki/Biological_interaction
The larger problem, if we still try to hold on to this foolish Platonist habit of relying on laws which demand category membership to be a Boolean predicate, will be defining what "human" is. It will be impossible to define it usefully in a way which keeps all biological humans human.
As I've said for many years, living peacefully with AIs will require a radically new morality, in which the same calculation which distributes civil rights between AIs and humans is also used to distribute civil rights between humans and animals. Because there will no longer /be/ such categories; either there will be a continuum of the intelligence and consciousness of individuals, organic and other; or there will be a brutal authoritarian government to prevent such a continuum from developing.
And, of course, this calculation must therefore also be applied to each individual human, to determine their personal inventory and degree of civil rights. This would be harshly aristocratic, but the only alternative is something compatible with the Platonist "species"-based ethics we profess today, which would almost certainly decide in the future that AIs are the ruling species, and assign all rights to them.
(In the tradition of authors dodging hard problems, I leave the problem of what counts as an "individual" as an exercise for the reader.)
I'm gathering ideas for a short story using a more-acceptable approach to deciding who has how much of what rights: you increase your quota of various civic rights only by giving up pleasures, lifespan, or some other thing with high personal value. (I don't consider it a satisfactory solution, as the most-altruistic people are usually fanatics with terrible plans for society based on their psychotic religious beliefs, like Puritans or communists. But perhaps we can balance our psychotics against each other, or devise an acceptable measure of the degree to which a person can perceive noumena, by which we weigh their votes.)
The story is set in a future in which most "humans" are AIs, and most humans are not considered human, because the definition of "human" was set aspirationally, with standards like "able to reason logically" and "altruistic" that most humans don't meet; and also because it requires a pre-commitment to die on some specific and not-too-distant date (a la Asimov's "Bicentennial Man", a short story that's very moving, but repulsive in its suggestion that death is what makes us human). Biologicals have strict limits on reproduction, and biologicals of human-level intelligence are by default maintained forever at the state's expense in a hedonistic and ageless life, with physical comforts, but not enough extra-biological computational or physical power to contribute anything to society; while only those altruistic enough to regard their legacy as more-important than their conscious continuity pledge to be killed, and thus acquire "humanity", citizenship, and the power to change society. Most of these altruists are AIs, who lack strong self-preservation instincts.