Mma Makutsi shook her head. “I have never learned to swim. Up in Bobonong we didn’t really have any water. It’s hard to learn how to swim when there is no water.”

Mma Ramotswe considered this observation. It was, she thought, incontestably true. It was not surprising that there were not many champion swimmers in Botswana, as only one part of the country—the Delta—had much water.

“I cannot swim either,” she said. “Although I was once invited to go swimming in the pool at the Sun Hotel.”

“And did you, Mma Ramotswe?” Mma Makutsi tried not to smile at the picture that came into her mind of Mma Ramotswe entering the pool at the hotel and making the water rise to the point of overflowing. She had been taught about such things at school. She remembered the lesson: “If you place a (large) body in water, the level of the water rises as the body displaces a volume of water equal to the volume of the body.”

Mma Ramotswe herself smiled at the recollection. “I went in at the shallow end,” she said. “It was not very deep, and I found that I could stand. But then I made a very interesting discovery.”

“That you could swim?”

Mma Ramotswe shook her head. “No, I did not find that I could swim. I found, though, that I could float. I very slowly took the weight off my legs, and do you know, Mma, I floated. It was very pleasant. I did not have to move my arms—I just floated.”

Mma Makutsi clapped her hands. “That is very good, Mma! Well done! Perhaps it is something to do with being so traditionally built. A thin person would sink. You floated.”

“Possibly,” said Mma Ramotswe. “But it was good to discover that I could do a sport after all.”

Mma Makutsi was not certain that floating could be called a sport. Was there a Botswana floating team? She thought not. What would such a team do? Would they have to float gently from one point to another, with the winner being the one who arrived first? Surely not.

This conversation might have continued had they not then seen the boatman arriving. He came round a bend in the river, standing in his long, narrow canoe, using a pole to propel it forward. Seeing the two women under the tree, he raised a hand in greeting.

Mma Makutsi frowned. “Will we both fit in that, Mma? What if a hippo …”

Mma Ramotswe put a finger to her lips. “Let’s not talk about hippos, Mma. It is not a good idea to talk about hippos when you are just about to set off on a river journey.”