is this also true of aboriginal tribes in pre-European days? And clans in Scotland, tribes in Africa?
If these are anything like tribes in mountain gorillas and Australian aborigines, these packs are not permanent fixtures, but are born from a single individual who gathers others, grows and fights for increased territory and members and die off due to various factors, to be replaced by new packs.
In other words it would just be coincidence that each wolf pack would currently have a similar amount of territory.