The wanderings of animals / by Hans Gadow.

  • Hans Friedrich Gadow
Date:
1913
Catalogue details

Licence: Public Domain Mark

Credit: The wanderings of animals / by Hans Gadow. Source: Wellcome Collection.

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    The making of deserts is still going on in various parts of the world. It is quite likely that many of the Central Asian desert regions were more habit¬ able even within historic times, and that, when their conditions changed for the worse great migrations of the people were the result. (See Sven Hedin’s and Aurel Stein’s descriptions of the sand-buried cities of Tibet.) The same applies to the extensive ruins in Arizona, New Mexico and North Mexico, affording incontestable evidence of former thriving populations. Now, what applies to people, applies also to other animals. The change of a country from bushland or a fertile prairie into a semi-desert may sweep off all the original inhabitants if that change is quick ; but if it is slow and gradual, many plants and creatures will have a chance of adapting themselves to the new conditions. Such conditions are: (1) scarcity of water, especially rain. (2) Abundance of sand and dust. (3) Great variations of temperature, not only with the seasons, but often daily. For instance in the Mojave desert it may be insufferably hot in the daytime, under a broiling clear sky with shade tem¬ perature far above 100° F. ; shortly before sunrise, owing to the unchecked radiation the water freezes in an open pan. Before sunset you do not know where to hide from the heat: amidst an ocean of glaring sand, with sandspouts swirling over the
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