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The glare of outdoor lights illuminates a small patch of ground and
prevents seeing hazards beyond the area.
Why can’t we accept this
nocturnal environment for
what it is—dark?
Over 60 percent of all biology
depends on and exploits the
darkness of night. Indeed, using
the new science of scotobiology
(the study of the biological need
for periods of darkness), we are
only starting to understand how
critically important darkness is
to our health and well-being.
Animals unconsciously use
the natural light to cue and
moderate their behaviour. The
fall of twilight is a biological and
behavioural cue that’s critical to
their survival, but artificial light
extends twilight throughout the
night. We know that our light is
artificial, but most other speciesdo not: it fools their biology
into thinking it is not yet night,
causing inappropriate activity
for some and dormancy for
others.Ever wonder how animals
know when to prepare for
winter—without a calendar?
By the time it begins to get cold,
it is too late to gather enough
food stores for winter or to
begin migration. The falling
temperatures of autumn are a
warning, but an unusually warm
autumn could prove deadly.
Nature has evolved a more
reliable cue: animals use the
shortening daylight as a harbinger
of winter, creating an urgency
that is felt by many species.