Sex at a depth of twenty metres is a languid affair, without obvious passion, but with a balletic grace that belies the 40 tonne weight of the animals. Their great white ribbed bellies were turned upwards towards us, a group of humans splayed out on the ceiling of their cerulean world in wet-suits and snorkels.
|Love in the deep blue|
But this menage a trois, two males and a female, seemed unphased by our presence. Occasionally they surfaced, perhaps ten metres away, bodies as big as a bus - obsidian black on the upside, shimmering white beneath.
Their heavy-lidded, seductress eyes seemed half-fixed upon us, and half-fixed on the ballet they were executing in clear blue water. On the occasions they rose to the surface, their great tail flukes smacked the water like a crack from a pistol. Several times a male - intending to impress the female, leaped from the water ('breaching') with an exhibitionism that seemed truly mammalian.
The males sing complex, extended songs while mating, signalling their credentials to the female, who listens to the call, and makes her choice accordingly.
Incredibly, this trio rumpty-tumpteed for three-quarters of an hour beneath us, an apparent exercise in playfulness that seemed as human as it was cetacean.
Humpback migrate every year from the Antarctic regions, where they feast on krill, fattening themselves for the fastening months in the warm waters off Tonga. In these regions, they mate and give birth.