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Adaptation |
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Survival in the Desert
With the support of the Ministry for the Environment the
numbers and behaviour of the Wild Horses have been scientifically
documented since December 1993. Numbers fluctuate according
to the quantity and quality of available grazing. After
the drought in 1992 and the resulting drive to catch the
horses, their number increased from 110 (1993) to 149
(1997). It dropped to 89 during the drought of 1998/99,
but had risen to 147 again by April 2005. In order to
maintain the genetic diversity the number should not drop
below 100. According to estimates the area can support
a maximum of 160 horses. |
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The Wild Horses of the Namib and
their 'God', the rain. |
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The adaptation of the Namib’s Wild
Horses to their habitat is not genetically evident. Reports
about extraordinary resilience may safely be relegated
to the realm of myth as well: many of the animals which
were caught during the drought of 1992 and taken to farms
succumbed to horse-sickness and other ailments. Adaptation
can rather be seen in their behaviour: patterns of feeding
and drinking, resting and playing match available grazing
and prevailing temperatures. |
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'Work'
and 'Leisure'
During dry conditions, when grazing becomes scarce,
the horses basically have to ‘work’
for the quantity of nutrients they need. Then they
cover vast distances, feed wherever possible and
rarely play. Visits to the drinking trough are put
off for as long as possible. In contrast to domestic
horses, thirst causes them very little stress. During
the hot summer months (November to March) they come
to drink at average intervals of 30 hours, while
during the cool winter months (May to September)
intervals average as much as 72 hours.
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| The centre of the horses’
life: the drinking trough at Garub. |
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When good rains have brought forth fresh
grass and numerous flowers the Wild Horses adopt a ‘leisure
mode’: they feed at night, and as there is no need
to cover vast distances to get their fill they remain
close to the drinking trough for longer periods of time.
Up to 80 percent of the herd gathers there. They drink
every day, regardless of temperatures, and play and rest
a lot. Their leisure time offers the best opportunity,
of course, for watching them and taking pictures... |
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'Dung
as Supplement
Apart from grass the Wild Horses also eat
their own dry dung. This does not mean that
they are desperate - it is natural behaviour,
also seen in domestic horses if they have
access to dry dung. The dung of the Wild Horses
contains almost three times more fat (1.99
percent) than the area’s dry grass (Stipagrostis
obtusa – 0.7 percent) and almost twice
as much protein (6.1 instead of 3.1 percent). |
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| Since horses are no ruminants,
eating dung is the only way to absorb nutrients
which have been excreted undigested and in
concentrated form. The dung, however, is merely
a supplement; less than 1 kg of dung is eaten
for every 7 kg of grass. Thus there is no
danger of harmful substances accumulating
in the horse’s system. |
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| By eating their own
dry dung the horses absorb undigested nutrients. |
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© 2007 Nature Investments (Pty) Ltd |
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- More pictures at www.namibhorses.com
- For a detailed media release see
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www.gondwana-desert-collection.com
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