John Hopkins

He seems determined to stick on her, shifting his body to keep her by his side.

The animal flips around, deftly repositioning Nan on his head.

Down to her right, a pectoral fin the length of a pickup truck swings through the water like the mechanical arm of some giant machine reaching for her.

She pushes herself away, trying to avoid being pulled under by that formidable, barnacle-encrusted limb.

By now though, Nan has started to notice something.

The whale's body language doesn't appear aggressive, even as he tries to tuck her under his fin.

If anything, he seems protective, less like an attacker and more like a parent trying to shield its offspring.

It deepens the mystery about what is happening.

His mannerisms seem gentle, not threatening.

Still, that could change at any moment.

When the whale momentarily lowers his peck fin, Nan seizes her chance.

She slides off his back and swims away until she's reached a distance of a few meters.

Then she turns and eases herself backwards, pushing the water down with her arms, looking back at the whale side on.

For a moment, curiosity supersedes any fear, and Nan just stares at the giant creature looking back at her.

What is going on here?

Then, as she treads water, Nan glances over to one side, where in the distance she can see the shadowy shape of another whale coming towards them.

Rays of sunlight filter through the murky water as Nan squints through her snorkel mask.

The second whale gets nearer and nearer, and as it does, she clocks something unusual.

Its tail fluke is not moving up and down as a whale should, but swishing from side to side, a slow, menacing motion.

Then Nan's body stiffens as a chill runs down her spine.