Many beloved pets are remembered forever by their owners. As we see in his final moments, for example, Ethan certainly remembers Bailey, his Best Pooch Forever.
But the dog's mother and siblings in his first life, as Toby, are quickly forgotten, and they're never remembered again. Such is the fate of dogs who are "rescued" from the wild, yet not taken to loving homes. Were they even reincarnated? We'll never know.
Anyway, Mother teaches Toby one thing: "Avoid men at all costs. Fear them" (1.25).
Toby sure didn't listen, did he?
Men lead to the deaths of Mother and two of Toby's siblings Fast and Sister. Hungry, not so ironically, dies of hunger before men find the doggy family, although the reason the dogs were hiding and starving in the first place was out of fear of people finding them.
So what's the issue—the people or the fear? Is Toby loved by humans because he does not fear them? Or does he give up his fear of them so that he can be loved, in essence selling out the rest of his family for his own survival?
Toby never really cares much for his doggy family. As he says early on, "I couldn't see that my brothers and sister had any purpose whatsoever" (1.2). In his doggy mind, Toby is the puppy version of a special snowflake: he has a purpose, and he actually gets jealous when he feels like his doggy bro Fast has the nerve to act special. "I'm special, Fast's dazzling star-shaped spot seemed to be declaring to the world" (1.5).
Perhaps Toby doesn't have a purpose at all; instead, he has a need to be special, and that is what leads him to convince himself that he has a greater purpose? Okay, maybe not, but we never said we were experts as canine logic.