A cruise along the Zambezi, a few safe kilometres before a slow-flowing river becomes the smoke that thunders over Victoria Falls.

’This river is so wide, at least a kilometre’ I say to the Captain. ‘You’re looking at an island in the middle’ he replies. ‘The river is twice as wide.’

As the sun softly sets, four elephants wade into the water, then start to swim across the Zambezi. Elephants can swim? Yes – and well. OK, then why? Why do elephants cross the Zambezi?

‘Food’ says the Captain. ‘It is their way to make sure they have enough, every day.’ Elephants, it seems, know how to be sustainable. If a daily swim across a broad river improves their odds of survival, elephants do it. No questions asked. While humans hire lawyers.

Towards the end of the swim, one elephant mounted the other. The Captain affirms we are witnessing an intimate moment. “We’re all less heavy in the water.”

Sustainability is such a loaded word, weighed down with dull thoughts of sacrifice, of giving up today’s pleasures for the sake of an uncertain future. We are painted bleak pictures, assaulted with guilt in the hope of atonement. Perhaps that is why we don’t really listen. Where is the joy?

How can you practise sustainability, sweetened by instant gratification? Ask any elephant. Or us.