Underground Elephants

   Every night, a string of African elephants emerges from the forest and makes its way to Mount Elgon, a dormant volcano on the Kenya/Uganda border. The elephants are on their way to spend the night in the salt mines.

Underground elephants

   Mount Elgon is near the Great Rift Valley, which is an enormous tear in the Earth's crust that slices through East Africa from the Red Sea in the north to Mozambique in the south. The valley has a history of massive earth movements over millions of years, and volcanoes are scattered over the landscape.
   Wind and rain have eroded Mount Elgon to leave its crater 6 miles (10 km) wide and surrounded by a ring of small mountains. In the valleys between the peaks, large cave systems run into the mountain sides. One of these systems, Kitum, is the elephants' destination.

   BURIED ESSENTIALS
   In the mountain areas rainfall is heavy and many mineral salts are washed from the soil. So the plants on which the elephants feed are devoid of the salts essential for a healthy life. The elephants therefore obtain their salts from the cave's enormous 'salt licks', formed from hardened ash when the volcano was active.
   Affer arriving at the wide, low entrance to Kitum, the elephants pass by a waterfall then gingerly pick their way in the darkness across a floor strewn with fallen rocks and crisscrossed by deep crevasses. The huge animals move slowly and deliberately, one behind another. One false move could be their last-the skeletons of several baby elephants lie in the bottom of a deep crevasse. Youngsters are reassured by the guiding trunk of an older female as they move carefully to avoid the dangerous drop.
   Back to daylight After spending part of the night underground in a cave digging out salts, elephants return to the surface at dawn. This extraordinary night shift is becoming increasingly rare because the elephants are being slaughtered for their ivory tusks.
   Then each beast picks up a piece of rock with its delicate trunk tip and delivers it to its mouth to crunch with its enormous molar teeth. Elephants that are the most frequent visitors to Kitum have short, stumpy tusks - the ivory has been worn away by many nights of digging.
   The elephants remain in the caves for about four or five hours each night. They do not dig out salt all the time, but crunch away for about half an hour, and then sleep. Outside the caves the night temperature drops considerably, usually to about 8 °C (46 °F) and sometimes to below freezing. The caves, however, stay at a comfortable 14 °C (57 °F), with high humidity.
   The large matriarch who usually guides the elephant herd into the caves leads them out again. In the morning. her loud, bellowing 'reveille' reverberates round the cave and warns the group that it is time to leave.
   Often the elephants are not alone in the caves. Swallows and swifts nest in hollowed-out fossil logs, the remains of ancient forests felled when the volcano erupted violently ten million years ago. These ancient trees can be seen in the cave roof, with roosting bats hanging from their petrified branches.
   Buffaloes, antelopes such as bushbuck, water-buck and duiker, as well as troops of monkeys and baboons, all take part in the search for vital minerals. They lick the crystals in the cave walls, or gather up the tiny scraps of debris left behind by the elephants. Within the caves they are safe from marauding predators.
   The Kitum caves may not be a natural feature. It is possible that the elephants themselves have excavated them by mining the salts - generations of them digging over a period of 100,000 years. Yet in the space of two decades, because of the senseless slaughter of the elephants by ivory hunters, the incredible excavations have come precariously close to an end.