I dont get it. Something is missing.
Imagine an asteroid knocking the world off its axis and suddenly these animals found themselves on the new northern regions..... very very cold.
This is just a wild guess, but it makes some sense.
There were a whole bunch of mammals that went extinct about the same time, 12-18 thousand years ago or so.
And finding a dead baby mammoth frozen up there proves that it wasn’t man that all the sudden like killed them all off.
Something happened. Something earth-changing.