One review considered why the domestication of the wolf occurred so late and at such high latitudes, when humans were living alongside wolves in the Middle East for the past 75,000 years. The proposal is that domestication was a cultural innovation caused through a long and stressful event, which was climate change. Domestication may have happened during one of the five cold Heinrich events that occurred after the arrival of humans in West Europe 37,000, 29,000, 23,000, 16,500, and 12,000 YBP. The theory is that the extreme cold during one of these events caused humans to either shift their location, adapt through a breakdown in their culture and change of their beliefs, or adopt innovative approaches. The adoption of the large wolf/dog was an adaptation to this hostile environment.