The biggest population [of tortoises] lives in the huge crater of an extinct volcano called Alcedo.
Climbing up there was hard going. Each of us had to carry two gallons of drinking water, our own kit, and a share of the filming gear. The whole of the first day was spent walking over great fields of roasting black lava that lay on the volcano’s lower slopes. The next day we climbed to the crater rim, 3700 feet high, and descended into the crater itself.
The adults were about five feet long, but there were also some youngsters. ..The population up here, it seemed, was thriving. They seemed not to hear any sound we made as we walked up behind them, and only became alarmed when they caught sight of us.
It was the breeding season. The big males were picking quarrels with one another, emitting open-mouthed gasping snarls…Their mating technique is nothing if not straightforward. The male, having spotted a female, plods after her. When eventually in this slow-motion chase he catches up with her, he simply keeps on going and climbs up with his forelegs on to her from behind. There is much thudding and squeaking and sounds like that of heavy leather harness under strain. He then starts copulating with a stertorous rhythmic roar and sometimes lifts the female’s rear end clear from the ground.
We quickly pitched camp and started filming this primordial scene. Soon after midday the clouds started to accumulate and before long it was raining. Back at camp we discovered that not only were our locally hired tents not waterproof but two of them had been flattened, presumably by optimistic male tortoises. The night was a wretched one, cramped, cold and wet inside our leaking tents, listening to the rhythmic roars of the indefatigable copulating males and wondering when they might in the darkness make amorous advances upon us. It was an unforgettable beginning to our whole project.
David Attenborough - Life On Air