After the pole shift, fuel may be in short supply. Many cultures have learned to use animal heat for warmth during bitter winter months. For example, large Swiss mountain farm houses have accommodations for humans on the upper floors and for livestock on the lower floor. They are usually built into a hillside so that access can be had to either floor from the "ground" level. There are some ventilation holes in place to allow the warmer air to circulate up into the human quarters. This combination saves on heat and makes tending the stock easier during those rough winters because the farmer doesn't even have to leave the house to take care of the animals. This is a regular practice in the Himalayan mountains, specially in Tibet.