Biology Reference
In-Depth Information
of 1981-2 20% to 30% died according to Keith Leggett but that compares to 90% of domestic
stock, 40%-60% of antelope, and 80%-90% of Hartmann's mountain zebra. They can cover
200 miles in search of water over a few days. Unlike their eastern brethren that eat 400 lbs.
(range 220 to 600 lbs., 100 to 300kg) a day and drink up to 40 gallons a day, the desert
elephants can go for two to three days without drinking and are more selective in the
vegetation they eat. In the Kruger Park, an average 7,000 lb. elephants needs 450MJ (107
thousand calories) per day, and since about 40% of food intake, half woody, is digested, the
annual consumption is 23 tons per elephant and elephants only eat half what they break off.
Thus, in the Kruger Park it has been calculated that 10% of the woody vegetation on an annual
basis is consumed by elephants, in other words, and incredible 240,000 tons per population of
10,000 elephants. The feeding patterns follow three modes: stripping leaves, tearing off bark,
and pushing over trees, and in winter often also consuming some roots. Pushing over trees
allows them to get at the canopy and since fires do not kill trees taller than 5m, the destruction
of taller trees is due to elephants. Most survive this and sprout again from the copsed trunks,
except Marula trees that may struggle and knob thorn (acacia nigrescens) trees that usually do
not. Baobabs are stripped where they still exist since the younger ones have been destroyed by
elephants. It has been suggested that the reason baobabs in past thousand years were able to
flourish was because humans, particularly San Bushmen, controlled elephants by hunting the
smaller females for food. Killing females would need to have been done only at 3% to 6% rate
to control the elephant population (Whyte, 1998). Since elephants are not prone to disease or
much to drought die off, this is suspected to be the reason the elephant population was not
larger before the Arabic and Europeans arrival]. In 1974 the heaviest elephant ever recorded
was killed near Sesfontein and weighed some 12,000 kg, namely about 13 tons, and was 13.7'
at the shoulder. Another rogue bull that had killed 11 people was shot in 1978 and was 14 and
half feet at the shoulder on the ground and about 13 feet 10 inches standing up, the tallest ever
measured. Its foot print track circumference was over 5 feet. The extraordinary memories of
the matriarchs lead them to watering sites, like shallow areas in dry river beds where wells of
water can be dug. Of all land based animals, elephants have the largest proportional brains,
and like humans they have a large neocortex for advanced thinking and communication. They
have some 70 vocal sounds and 170 sign language methods for communication, including
through their soft foot pads used to pick up vibrations and allowing for them to communicate
with each other over a couple of miles. In Etosha, it has been found that elephants can pick up
vibrations from a charge 32 km away. With temperature inversion over the desert and the
cold-warm air interface, the sound waves can travel up to an amazing 100 km, a little like
radio waves bouncing off the higher stratosphere layers. They also help each other to defend or
carry the injured, recognize themselves in mirrors and if a mark is made on them in zoos, they
notice the difference. In zoo experiments, they will cooperate in pulling a log with two ropes
to gain access to food. Earlier hunters such as Gordon- Cummings, Harris, Livingstone,
Baldwin, Struthers, Selous, Beryl Markham, and Karamajo Bell remarked on the elephant's
ability to appear to disappear very quickly when hunted using some mysterious means of
communication, and the females returning to protect or carry injured bulls, and their mourning
over dead family members.
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