Humans are outdoor animals. Yes. Well done. A+. We even have opposable thumbs, which means we can operate door handles and make our own way outside. Or are you asking us to demolish our houses and live out in the farmland now?

We build homes for warmth and security. Even our nomadic ancestors built movable homes (tents, teepees, caravans, mobile homes, RVs etc.). Just because an animal is supposed to be outside, doesn't mean it has no benefit from access to an indoor area. The rules for survival fit animals just as much; 3 minutes without air, 3 hours without shelter, 3 days without water, 3 weeks without food. The numbers will be different, but if an animal cannot find shelter on a cold night, it's unlikely to survive (unless specifically adapted for that situation).