Living underground, mole rats are sheltered from the Kalahari's worst extremes of temperature. We think of deserts as hot places. But nightly temperatures can fall well below zero.
At dawn, meerkats need to soak up the warmth of the rising sun to get fully active. The temperature in the Kalahari steadily climbs as high as 70 Celsius on the ground. Meerkats can only tolerate short bursts of activity in the morning and evening. This means they need to be very efficient at gathering food. So they quarter their territory, traveling several kilometers a day.
Tasty beetles and scorpions are common in this grassy desert. But finding them means spending a lot of time with your head in the sand. So meerkats are very vulnerable to predators. To protect the group, young males take turns keeping watch. This frees the others up to keep hunting. Scorpions have a lethal sting, but meerkats are fast as lightning.
The Kalahari's high levels of rainfall mean food is plentiful year round, one reason why this desert can support more large mammals than any other in the world.
Springbok are the most successful desert antelopes in Africa. With short, thin fur, they can easily offload heat by sweating. The white patterns on their coats help to reflect solar radiation. And they never need to drink. They can extract all the moisture they need from the most meagre desert plants.
But in southern Africa's deserts, there is a lurking challenge. Cheetahs shadow the springbuck herds. They ,too, evolve in the desert. Thinly-furred and lightly-built, everything about them is designed to deal with heat and speed.
-----------------------------------------------------------------------------------------------
words:
1.meerkat: 猫鼬
2.offload:to get rid of and pass on to another卸下，排掉
(eg.): He does come to offload the blame for launching the transmitting tools to market.
