Reindeers do the most amazing thing when they feel threatened…they create a cyclone.
They start running together in a spiral, tucking the youngest and most vulnerable in the center for the most protection. One study showed that reindeer in captivity do the same thing (when there are at least 20 to 25 of them), always running counterclockwise.
It’s breathtaking to watch the power of this primal, instinctive act.
https://www.livescience.com/64778-vikings-reindeer-cyclone.html