When sleeping in a new place, new home, hotel, or vacation I often have this fairly stressful reoccurring dream of living in a slightly dilapidated house (different every time). I often wake in the night feeling very confused where I am or if the dream is real (if that’s where I actually live) it takes a few minutes for me to figure out what’s what.
I’ve often thought that this was probably something left from when we were living in caves or hiding from predators were you need to be sure that a new sleeping place is safe.
More likely the worry is other humans. We are territorial. Sleeping indicates a confidence in one's safety in a location. It can be a sign of dominance. Watch any cat sleeping in a dog's bed just to show who is in charge. I suggest that when in a new place we worried more about the locals not wanting us in their territory than the lions wanting to eat us.
I've actually experienced both sides of this in a way. Usually when I go camping, I have the mentioned brain-half-tuned-in effect. However the first time I went to a Regional Burn (a mini-Burning-Man-esque offshoot event) and camped right in the middle of Tent City, I felt completely at ease. I was quite literally surrounded by my tribe, and it was a really comforting effect.
It definitely made me ponder about Dunbar's number and what tribal life must be like.
Coincidentally, the three demarcations at this particular burn, the theme camp (~30 people), the field/block (~100), and the whole burn (~500), correspond to the lower end of the types of groupings Dunbar observed.
> Dunbar noted that the groups fell into three categories—small, medium and large, equivalent to bands, cultural lineage groups and tribes—with respective size ranges of 30–50, 100–200 and 500–2500 members each.
Anyone who has tried car/van camping in public should be familiar with this feeling. While sleeping in my van I've had plenty of nightmares where the nearest neighborhood forms an angry mob to have my vehicle towed away.
I usually have the opposite phenomenon. I go traveling for a few weeks sleeping in different places with no issues whatsoever. But then when I'm back home I find myself waking up in the middle of the night not grasping where I am for a few minutes.
I’ve often thought that this was probably something left from when we were living in caves or hiding from predators were you need to be sure that a new sleeping place is safe.