Sperm whale ’poo-nado’ – murky waters but clear signal?

In a dramatic ‘racheting up’ of the old joke which runs along the lines of “who’d want to swim in the sea?  After all, that’s where fish go to the toilet” comes the story currently receiving much media attention, concerning a group of free divers photographing sperm whales underwater off Dominica under government permit.

Visibility turned to near-zero as the divers were suddenly engulfed by a giant cloud of sperm whale poo which rapidly spread to cover over 30 metres, reportedly whipped up into a ‘whirlwind’ by the whale spinning on its side and fanning its massive fluke (tail).

Why might whales do this?

Described as a ‘poo-nado’ by Canadian underwater photographer, Keri Wilk, it is speculated that this behaviour could be a defence mechanism, warning off anyone approaching too closely. This is  similar to skunks spraying or fulmar chicks vomiting as a deterrent; and indeed pygmy and dwarf sperm whales use a fascinating deterrent dubbed the ‘squid tactic‘ whereby they can eject a dense cloud of over 12 litres (3 gallons) of dark, reddish-brown inky liquid from a special intestinal sac  to confuse or deter potential predators.

Although the press is widely reporting this behaviour as ‘rarely seen’, it may not be that uncommon.  Certainly this has also been witnessed by professional film-maker and underwater photographer, Andrew Sutton, and author and broadcaster, Philip Hoare, both WDC ambassadors, who have filmed these whales under licence in their professional capacity.  Philip commented: “Fascinating to read media coverage of a sperm whale ‘poonado’ off Dominica.  Andrew Sutton and I both experienced similar incidents with sperm whales, in the Azores and Sri Lanka.  In the former, a sperm whale calf seemed to use defecation as a clear (or not so clear!) ‘smokescreen’ when I inadvertently came too close to it.  Was this a nervous loosening of its bowels, too?  Perhaps that is, in itself, an evolutionary development.”

WDC’s position is that – with the exception of a very small number of professionals working under strict permit conditions and using their outputs to directly benefit whale conservation  –  the rest of us should not attempt to get into the water with whales or dolphins, for the safety and welfare of both parties.