Heptner's maps clearly show tigers from south-eastern Siberia travelled to the north and, more often, to the west. They also show these tigers had reached Lake Bajkal and regions well north and west of that lake quite a long time ago. Most of these wanderers, over time, settled in riverine forests in regions east of the Caspian Sea. Another, smaller, group settled in rugged and mountaineous regions west (eastern Turkey) and south (Iran and Afghanistan) of the Caspian Sea. It is not known if these subgroups had been seperated long enough to develop into distinct local races.
Here's a map of the distribution of tigers in regions east of the Caspian Sea (from Heptner and Sludskij, 1980).
