It's definitely true that people change people. The characters of the people you are friends with make a difference to what you're like, especially the friends of your youth. When I think about how life would have been different if I had done Maths or CompSci as an undergraduate the thing that seems really crucial is that I wouldn't have met people who helped to shape my character. Also it seems to be the case that some company makes one feel more alive and alert than others. (The people on my course are young and often make me nostalgic for the dry humour of people with PhDs but no job prospects.)
I think that's also the case with animal company. I think spending time with horses, or dogs, or any animal, forces you to be calm and patient, and makes you a little less human in a good way, a bit more part of the immediate world, and a bit more focused on affection. I really miss having pets.
I like to think that this also has an effect on the animals too. At this point I may be moving into wishful thinking. Definitely my brother would say that keeping animals is a sort of slavery, and that because I like to do so I imagine that there is a positive side for them too. He says that if the pet loves you that makes it worse not better, because the pet has no choice in the matter -- it's just a form of Stockholm syndrome and sick. (Last time we talked about this I pointed out that he had done the same thing to my nephew, who has no choice but to love and utterly depend on his parents, but he says that's different because children grow up -- I'm not convinced, and to me it seems more of a big deal to create a human who is totally emotionally in your power than to do the same thing to an animal with less complex emotions and easier needs. I admire in both senses the chutzpah of people who decide to have children.)
But anyway, with the proviso that I really want to believe this, I think that animals are changed a little by human contact. The pets I've had have been dogs and rats, and they both love to communicate with humans. Am I reading too much into it because I loved to communicate with them? It seemed to me a bit like the good conversation which is about the only thing I miss about Cambridge -- it made me feel a similar sort of mental satisfaction, though of course it's a very different sort of communication. Sentimentally I like to imagine that spending time with humans made my pets also feel a sort of satisfying mental alertness, that it enlarged their world.
Anyway this is just a roundabout way of introducing a very interesting video of a bonobo ape called Kanzi who likes to light fires and toast marshmallows. The woman with him attributes this to a film he saw when younger, which is culture I suppose.