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Observations: Wonders of Creation — Sophisticated
Cold Protection in the Negev
by Yated Ne'eman Staff
How do animals survive the extreme conditions in the desert?
New studies reveal glimpses of the wonders of Creation:
"smart" means of protection that allow animals and plants to
live and function under conditions of dry heat or freezing
temperatures. In the science journal, Teva Hadevarim,
researcher Yigal Granot of the Sdeh Boker Desert Research
Station notes that every winter, meteorological stations in
the Negev record temperatures dipping as low as 20 degrees
Fahrenheit at sea level. Clear winter nights in the desert
are colder than cloudy nights because, in the absence of a
cloud blanket to retain the heat, sunlight absorbed during
the day is released into space very quickly.
At such low temperatures animals try to hide in tunnels and
burrows underground, where temperatures change at a slower
rate. Other animals hide under rocks, but this does not
provide adequate insulation. In the blood of the yellow
scorpion researchers recently discovered an antifreeze agent
that lowers the freezing point to 20 degrees Fahrenheit.
Other animals are covered with fur or feathers and many small
birds can be observed fluffing their feathers on cold winter
days to trap air, which is a highly efficient insulator.
The color black, common among goats, beetles, snakes and
other animals, helps them cope with cold conditions.
Based on the assumption that animals would not have
coloration that makes them clearly visible to their predators
unless it offered a distinct advantage of greater importance
to their survival, researchers began to turn their attention
to black animals, which stand out prominently against the
yellow desert background. Indeed, studies of the Bedouin goat
found that although they have a system to regulate body heat,
when they set out in search of food in the early morning
hours the goats' black hair is used to absorb heat from the
sun's rays, gaining them extra time for grazing. Beetles,
which are cold-blooded, also absorb heat from the sun during
the cold morning hours.
Other animals, such as the desert moss crab, spend the fall
and winter in a state of pseudo-hibernation inside a tunnel.
During the few hours they leave the tunnel their dark
coloration allows them to absorb 60 percent of the sun's
rays.
This sophisticated innovation of maximizing the sun's rays
can also be found among certain plants, particularly sprouts
of annuals sensitive to the cold. Most desert plants are
equipped with a thick, natural covering to provide
insulation, but young sprouts are liable to freeze.
Scientists say that during the first two days of life the
majority of plants that sprout after the first rain have red
coloration that later changes to green. The red comes from
anthocyanin, a pigment known for its ability to absorb heat,
and thus the sprouts are able to keep warm until their
photosynthesis apparatus (which generates energy) matures.
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