The Russian Resident Killer Whales are a lesser known population of killer whales that has been studied by Far East Russian Orca Project since 2000. With fairly little known about their ages and family structure, except when new births occur during the study period, most of the adult individuals have unknown birth years, instead being listed by being "at least more than x years old" in my database. Matrilines are also instead called Families, as they aren't separate enough to be considered separate pods, but family connections aren't known enough to confirm matrilineal status (in most cases, no lead female or connection can be drawn between individuals of separate families).