At work here is the human inevitability of the pain/pleasure principles, what is often misrepresented as our unavoidable “selfishness”.
The human interacts and relates to the other animals based on his uses for them with regards to pain and pleasure.
The cat is useful for companionship, exercising the nurturing/biophilic and eliciting the positive brain states of “loving an animal”. The horse may also have this relationship with him, though it looks more like the horse is there for work.
The other animals present are also utilitarian in their relation to the human, bringing the pleasure of food, economic security, and a place in society as the provider of food. Being a caring animal, the human maintains emotional distance from these animals to minimize his pain.
The animals not present (wolves, gorillas, etc.) have not proven useful in a domestic sense, or haven’t been widely culturally adopted (i.e. a subjective contrived sense of pleasure has not been idealized in most other animals; some people have monkeys or other pets though). They may present threats/pain to other animals, or simply hold no pleasure through their inability to break them to human preferences.
Other humans, typically not involved in the production of food on sustainable, smaller scales (nor large, for the matter) widen their circle of nurturing pleasure utility to include all animals, which is more sustainable for them, their lives not requiring the direct conflict of the nurturing and feeding roles, and its painful effects upon the human emotional tendencies. They do subject themselves to more pain in light of the reality of much deliberate non-human death in their world, however, this cost can be arguably written of at the species level, where symbiotic relationships with other animals, and the quality of human/mammal favouring environmental conditions are protected and brought to the attention of other humans who are increasingly disconnected from these realities.
It is important to underline that both of these humans (representative of two points on an infinite, multifaceted spectrum) are responding to their own pain/pleasure principle, or seeking to minimize pain and maximize pleasure, in both the more fixed, and more fluid and self-directed aspect of their human being. The suffering of other animals is only consequential to the human via this pathway (or rather, the physiological and psychological systems, and the evolutionary inter-dependences between species and members and environments that they constitute); the pain of the animal does not “actually touch” the human. Restated, the human cannot, in the sense our language and narratives conceive, be anything but “selfish” or interested ultimately in anything but it’s own experience of pain or pleasure. In some humans, this may be entirely represented by the subjective definition pleasure as absolute non-violence. Others, usually by circumstantial crisis and necessity, can strip the moral consideration from even the death and consumption of other humans, though only for a short while, and with psychological repercussions. Most people exist in between, and with their own cultural peculiarities regarding those animals they “love” and those they “use”, both actions essentially being a “use”, though this is distorted by the nature of our emotional experience, if not more objectively examined.
Due to the inherent lack of any ultimate, defining morality in reality itself (morality being a product of an organism’s experiential nature and subjective between species and even among members of the more socially complex species), whatever strategy results in the subjectively defined “success” of the species, or its objective survival (which, when selected as the measure of success, is itself actually a subjectively defined success- there’s no reason that a species surviving is inherently a “good” thing) is hence a valid one, and a valid moral one at that.