Homo sapiens has chosen to venture into what is for him an unnatural environment and he does so at his peril.

Reykir realized her eyes were in pain, as she was flying in the daylight, an unnatural environment for a nocturnal beast.

Calon becomes bitter, and believes that it is his duty to "free" natural humans from this unnatural environment.

Sleep laboratories are an unnatural, awkward environment for sleeping.

Space is an unnatural environment, and it takes an unnatural effort from unnatural people to prosper there.

Still, the presence of women lent a little reality to what he remembered as an unnatural environment.

Their unnatural environment almost certainly contributes to the brain-related problems that preterm children develop, Als says.

But a Mississippi Delta catfish farm with as many as 1,000 acres of ponds is a decidedly unnatural environment.

The Big U was an unnatural environment, a work of the human mind, not of God or plate tectonics.

All right, suppose the note was correct; maybe he did remember that other world, that gloomy quasi-life of involuntary expatriation in an unnatural environment.