onioning t1_j0zn6zo wrote on December 20, 2022 at 4:34 PM

Reply to comment by rocksfly in TIL Lake Baikal is located in southeast Siberia and is the oldest and deepest lake in the world, at 25 million years old and 1,700 meters deep. It contains 20% of the world's unfrozen freshwater and is home to a rich and unusual freshwater fauna that is of significant value to evolutionary science. by wisely_lined56

I'm speaking from memory here, so may have the details wrong, but if I am remembering correctly they haven't been there that long. It would be easier to explain if they had been around before the last ice age, because that would make the northern river route more plausible, but the timing doesn't add up. If they were a bit older than even that the western route would be more plausible, as those waterways were yet greater. But the timing doesn't add up, and they seem to have arrived after those easy routes were dried up or frozen.