The moment divers were caught up in a 30-metre wide bowel movement

Described as a 'poonado' by Canadian photographer, Keri Wilk, 30, the peculiar behaviour is thought to have been evidence of a rarely seen defence mechanism.

After spotting the aquatic mammal in waters off the small Island of Dominica, the four free divers began to take pictures as part of a government approved expedition.

But the routine dive soon took a turn for the strange when the whale began releasing wave upon wave of faecal matter right in front of their eyes. 

The marine mammal managed to create a whirlwind of excrement by spinning on its side and flapping its tail.

Although it isn't uncommon to see whales defecate before they descend, this was a bowel movement with a difference, spanning over 30 metres in diameter.

To make matters worse, Mr Wilk prefers to dive with just goggles and a snorkel as bubbles from scuba diving equipment tend disturb the whales.

He said: 'Four of us got into the water near the whale, then it slowly approached us, stopped, and pointed itself straight down before storm began.

'At first, it seemed like a regular bowel movement but rather than continuing its dive down, it remained at the surface and continued to defecate for a startling length of time.

'Four of us looked at each other with confusion, then back at the whale, expecting that any second its call from nature would come to an end.

'Instead, the whale bobbed up and down, spun in circles and waved the poo in every direction for several minutes while we just sat back and watched.

'The water was crystal clear, initially, and was the most idyllic Caribbean blue water that you could imagine.

'After a few waves of faeces were released and stirred vigorously by the whale, the water was like chocolate milk, I couldn't see my hand when I held it in front of my face.

'I had poop in my eyes, mouth, wetsuit, everywhere and I was soaked in it from head to toe. But, after leaving the cloud, it quickly washed away, and didn't leave a smell on us.

'I did take an extra long shower once I returned to shore later that day, just in case.

'I've never heard of it happening before, and I don't know anyone that has had this happen, it very well could be the first time that it has been photographically documented.' 

(dailymail.co.uk)