Throughout the world, there are places where the wind piles sand into strange and wonderful hills and ridges called dunes. All sand dunes are somewhat similar they all need sand, water, space to form, and they are all constantly changing. However, each sand dune is different in its own way. Each sand dunes' shape is determined according to how much sand and what kind of sand is available to be blown into dunes, and also the direction of the wind is essential.
Alot of the sand you observe today was once part of a rock. Rocks may seem indestructible, but they are not. You can crush a rock down into fine sand particles. Nature has several ways of changing rock into sand.
Sand dunes are found in the coastal and inland deserts. A sand dune can be as small as an anthill or as tall as a skyscraper. All sand dunes are formed the same way, every single one is a pile of sand built up by the wind. Once the sand has been picked up by the wind, it will go wherever the wind carries it. Even though most sand dunes are made of the same material and formed in the same way, they vary widely in appearance. For example, there are four major types of sand dunes:parabolic, barchan, transverse, and longitudinal.
Types of Sand
These dunes are usually
straight to abnormally sinuous dunes. The straight
varieties are often called "sand ridges" and
the sinuous varieties are called "seifs". The
lengths of individual dunes can range from a few meters
to many kilometers. The smaller longitudinal dunes can be
3 to 4 meters high. The strength of the wind pushes the
sand and forms long ridges that are parallel to the wind
that pushes it. Since the slip faces have a temporary
alternation the flanks can be steep which causes loose
sand to be found on the top, sides, and near the top of
the ridges. The temporary alternations that occur are
caused by changes in the direction of the wind. They can
range from daily to seasonal according to the regional
Life In Sand Dunes
Most people may think
that just because a sand dune is a pile of sand that
there can't be any form of life living in there, but
they're wrong. At a closer glance, you realize that there
is both animal and plant life on a dune. A variety of
animals have adapted to survive in this unusual habitat.
Plants such as poison ivy, wild lupine, and honeysuckle
may grow along a dune's surface, while cottontail rabbits
and grasshoppers often live in dead trees buried
underneath a dune.
Animal Life In a Dune
Animals that live in sand dunes know that the sand just beneath the surface is cooler. That's why they remain underground during the hottest hours of the day. One of the factors that dune animals must face is to know how to conserve water. The kangaroo rat is a great model of water conservation. From the seeds and vegetation the kangaroo rat eats it gets the water it needs. Its urine contains so little water that it turns into solid when it comes in contact with the air. The kangaroo rat has natural defenses that help protect itself while living in the dune. Such as its long tail, which it uses to keep its balance as it escapes from enemies such as the sidewinder rattlesnake and the kit fox. Also the fur around the kangaroo rat's toes turn its feet into "sandshoes" which prevent it from sinking into the sand.