Here again is circular reasoning, that because everything is presumed to have evolved from a primordial soup, this would have to be true of consciousness and signs of morality, in the form of an assumed altruistic instinct of animals, to perhaps help one another or feel distress observing the suffering of a member of their species. This, too, is circular reasoning, assumed in the absence of evidence that evolution is behind creation, and so that presumed “random process” that has no reason or logic behind it might be capable of causing everything, through a process of natural selection, because it might have survival value. If one has respect for fellow members of one’s species, that could help the individuals survive in helping to take care of its group, and so on. That proves nothing truly about morality, other than self-preservation is a motivation for a being capable of having at least a primitive understanding of cause and effect.
But here again, science is turning the world upside down, assuming in advance where everything comes from. Science assumes everything comes up from the bottom and somehow reaches the top in a very refined and even elegant depiction of reason and logic, and even morality, as an important inner characteristic, as displayed most dramatically by human beings over and over and over again, even from a very young age. We can tell you with authority, because we created everything, that everything is indeed a creation and came from the top down. All species were created to be what they are, they are not a product of evolution. They were part of an ongoing experiment in a widening degree of orchestration and complexity, added to again and again, to build on what came before, to repurpose good ideas over and over in varied settings. So the fact that two species have similar biochemistry does not mean one evolved from the other to end up with some overlap in mechanistic functional characteristics, but only that what was a good idea for one was used for the other. So the fossil record might well show some things were present prior to more recently arrived species, but that sequence was not a consequence of random effects happening to give rise to the new variety of life forms—all were added purposefully and with a plan in mind.
So the fact that rats have a semblance of human altruism, as a behavior, is not surprising because the universe is love-based, so even predatory species can exhibit nurturing behavior, a true caring for the young, and this can translate into caring for familiar adults of the same species, or even strangers, because of a kind of self-identification. And noting another fellow being, in trouble, and personalizing their suffering with an understanding of what that could mean to them, will certainly get their attention, if not ruin their day. So the fact they might stop eating tells you little more than rats might well care about one another, because even such a primitive low-level demonstration of loving concern is not at all surprising in a life form created by the Almighty, because we put love into everything, in some form or another, if only in its beauty, to be enjoyed by other more intelligent species who can appreciate form as well as looking for things to eat without concern for appearance.