martedì 9 ottobre 2012

The Namib, a desert miracle: fauna (2)

There are also several species of very flat, rounded beetles of the genus Lepidochora, wich have developed an even more ingenious method of water collection.
This small coleopterans construct narrow trenches on the surface of the sand that run perpendicular to the direction of the fog-bearing wind.
The ridges of these trenches absorb more water than the surrounding undisturbed sand surface and the beetles return to extract the water from the sand ridges that they built.

But it is not only the fog that enables the great diversity of animal life to survive in the Namib; there are also large quantities of wind-blown plant and animal detritus that catch in the lee slopes of the sand dunes and provide food for many invertebrates and a few vertebrates.


Apart from numerous species of tenebrionid beetle and fishmoths that partake of this wind-delivered feast, there is also a lizard that specialises in feeding on the seeds of one bush, Trianthema hereroensis, which have been carried by the winds; this is the shovel-snouted lizard.

Sitting on the crest of a sand dune at between two and five o'clock in the morning, with a cold, moisture-laden wind beating against one's face and clothing doesn't appeal to everyone, but this is when the seemingly barren Namib Desert is at its best. 
The powderpuff-like golden mole has been moving around on the surface of the lower dune slopes, seeking out beetle larvae and legless lizards.

The web-footed gecko and the white lady are also out hunting for insect prey. 

The web-footed gecko is so named for an obvious reason, and this adaptation allows it to "swim" under the soft surface of the dune sand as well as walk more easily on the surface.

Foto di Swakopmund
Questa foto di Swakopmund è offerta da TripAdvisor.
 
The white lady is a large spider that shelters in burrows during the day, emerging in the hours of darkness to stalk its prey on the slopes of the sand dunes, but what is unusual about this desert arachnid is its escape mechanism. When threatened it forms its legs into the shape of a wheel and rolls rapidly down the dune slope.

Foto di Swakopmund
Questa foto di Swakopmund è offerta da TripAdvisor.

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