Tribes. These are likely the descendants of peoples pets left behind and isolated which combined with a short lifespan has treated a fairly unique population.
Is this adversarial selective pressure? They'd occupy the same niche, and so forming "tribes" inevitability implies competition for whatever scarce resource they have to share. Something in diet or habitat would become a limiting factor.
It would be fascinating to compare this to isolated speciation which can drive to weird gigantism or dwarfism. I'd imagine that the advantages of eg being social to humans played differently.
Seemingly the primary limitation is winter temperatures as workers are providing a long term food source. People also culled dogs right after the meltdown, and there’s been some effort to remove dogs from the area after that. Which again isn’t adversarial.
Main treat should be wolves in the same area that will chase off or eat all the dogs small and middle sized. Can explain also the distribution in the worse areas and the need to remain close to humans
It would be fascinating to compare this to isolated speciation which can drive to weird gigantism or dwarfism. I'd imagine that the advantages of eg being social to humans played differently.