Some incredible Alaska caribou footage from Golden Eagle Outfitters out of Kotzebue. North West Arctic Caribou here during the aggregation... estimated around 170,000+ animals in one group. This is has the "Planet Earth" wow factor. What I would give to see this in person. 

As the mosquitoes emerge in late June and early July, the caribou gather into enormous post-calving aggregations, sometimes numbering in the tens of thousands. For example, in 1987, over 93,000 caribou assembled in one group south of Camden Bay. The caribou seek areas where breezes and cooler temperatures reduce the harassment by mosquitoes, and when there is no wind, the caribou move continually. Cold winds offer relief from the mosquitoes and permit the caribou to rest and feed freely.