Deviation from light-dark cycles leads to reproductive failure, death, or predation in animals, and obesity, metabolic syndromes, endocrine disorders, and mood disorders in humans.

“It's striking to me that in all animals, besides humans, if they deviate too much from the appropriate exposure to light and light-dark cycle, they essentially don't mate and/or die and/or get killed off. But in humans, we are able to override that at least to some extent, but the ways in which we suffer appear to be things like obesity, metabolic syndromes, reproductive syndromes that are accompany the other syndromes, you know, endocrine syndromes, and mood and depressive disorders.”