For animals that live in social groups, communication is key. A huff can be a warning to flee or freeze, communal grunts can be a signal to the group that it's time to move on, and, in the case of African wild dogs, sneezing can trigger a hunt.

A new study carried out by a team of international scientists working in Botswana's Okavango Delta suggests that wild dogs use sneezing as a kind of voting system when making group decisions. While documenting the Delta dogs, researchers noticed an abundance of achoos that seemed to peak just before the canids went on the move. Analysis of several wild-dog interactions revealed an intriguing pattern: the more sneezing, the more likely the pack would be to set out on the hunt.

Wild dogs are highly sociable pack hunters and cohesion in the group is vital to successfully bringing down large prey. Before each hunt, the dogs perform an energetic ritual known as a "social rally" – a frenzied explosion of tail-wagging, head-touching and side-by-side dashing that is usually initiated by a single dog. Sometimes the rallies simply fizzle out and – in typical carnivore fashion – the dogs lie down and snooze. But other rallies end with the pack running off together, often to chase down prey.

To figure out just what triggers a hunt, researchers analysed 68 interactions from five different wild-dog packs in and around Botswana's Moremi Game Reserve, and they discovered that the dogs use sneezes to signal a positive response to a proposal from another pack member. "The more sneezes that occurred, the more likely it was that the pack moved off and started hunting. The sneeze acts like a type of voting system," senior study author Dr Neil Jordan said in a statement.

Of course, many social species rely on some kind of consensus signal when making group decisions. Foraging animals like meerkats communicate using a variety of calls, and will move to a new area in search of food only if a certain number of individuals – a quorum – agrees with the decision. Even some bioluminescent bacteria make use of chemical signals to communicate before lighting up.

However, this is the first instance of sneezing – or "audible rapid nasal exhalations", as the study authors describe it – being documented as a signal to motivate group consensus.

Wild-dog societies are not entirely democratic, though. In instances where alpha dogs initiated rallies, far fewer sneezes were required to get the pack moving. Lower-ranking individuals eager to hunt had to cough up a minimum of ten sneezes – three times as many as the dominant dogs – to see results.

The findings do, however, suggest that wild-dog societies may be more complex than previously thought. Rather than operating autocratically, packs appear to display "a more democratic process for daily activities and group decisions," study co-author Reena Walker told National Geographic.

But the findings are not entirely clear-cut. At this stage, the researchers are uncertain if the nasal blowouts are a voluntary form of communication, or simply a spontaneous bodily function. It's possible the dogs sneeze to clear out their nasal passages in preparation for a hunt as an involuntary response to some other clandestine form of canine communication that we are not yet aware of. Sneezing may be a "physiological response to a consensus already achieved through other signals that we did not observe," the authors note in the study.

What we do know for certain, though, is that the bigger the sneeze-fest, the greater the chance of a hunt.


Top header image: Mathias Appel, Flickr