The mountain was so far off that it didn’t seem to get much closer. Her legs were tired and her feet felt like heavy weights that she had to drag through the grass. The sun was getting higher and the heat was crushing. Her mouth was dry, even with the pebble still under her tongue, and she had a headache behind her eyes.

After a while they crossed more animal tracks. Bear knelt down to examine them.

“All sorts of animals here,” he said. “Not just elephants this time. Antelope and eland and a few other things.”

Evie knew what would attract lots of different types of animal in one direction.

“Water?” she asked eagerly.

Bear’s big smile told her all that she needed to know.

Soon they could see animals in the distance. All sorts. Some Evie recognised, like zebras. Some were harder to name, like the creatures that looked like massive cows with curled horns. There were several things that looked like deer, all different shapes and sizes with different styles of horn.

The animals were at the far end of a huge patch of bare earth. Evie and Bear had stopped beside a dark rock the size of a car. Evie started to walk off towards the animals, but Bear told her to hang on.

“The animals all come here to lick this, and we can too.” He broke off a pebble-sized lump from the rock and handed it to her. “It’s salt. After water, that’s the most important thing for your body right now, and we’ve been sweating buckets out without noticing. Salt makes your nerves and muscles work properly.”

Evie took it in surprise. It looked more like black tar than the white crystals she would expect back home.

“Isn’t too much salt bad for you?”

“You’re right. It’s all a matter of balance,” Bear said. “We’re designed to have a certain amount of salt in our bodies. Not too much, not too little. This’ll help us make it just right.”

Evie thought of her headache and her tired muscles. If salt would make her feel better, she was all for it. She had drunk elephant dung water, so she could do this. She swapped it for the pebble. It tasted better.

They made their way cautiously towards the animals, which were gathered around a water hole the size of a small swimming pool.

None of the creatures took much notice of the two humans. Evie wondered if the animals had some kind of truce going on when they were near to water. But just as they got closer, Bear stopped.

“And there they are,” he said quietly. “I knew we’d meet them eventually.”

He didn’t point, but Evie followed his gaze. And gasped.