For hiking in polar bear country, this answer cites a page that advices to avoid camping under the stars at all times. Yet people do go trekking on Svalbard, and I don't think the density of huts is ...
Some animals are big and dangerous and, when hungry, may realise that humans contain a pretty decent amount of meat. I've never hiked in such areas, but they do exist. Photo from Wikipedia, CC-BY-...