Biologists have found that they sneeze to vote. But not all sneezes are the same.
Animals do the most amazing things. Read about them in this series by Janaki Lenin.
We sneeze to clear our nasal passages of irritants or phlegm. In African wild dog (Lycaon pictus) parlance, a sneeze says ‘Let’s go hunting,’ say biologists.
To live and hunt as a group, everyone has to agree to do the same thing at the same time. If a few want to sleep while the rest wish to go on a hunt, the first group would be left vulnerable and the second one may not be successful. Gorillas, for instance, grunt back and forth to each other before they all rise up and leave.
An alpha pair rules African wild dog packs. Often, the dominant female prevents other females from becoming mothers. When she retires to a den to give birth, the rest of the pack cares for her and her pups. For many years, biologists assumed the dominant pair makes the decisions and the other pack members had no option but to follow.
Scientists studying African wild dogs in Botswana say decision-making is democratic to a degree, with members casting their vote by sneezing.
After lazing in the tall grass of the savanna, a few restless dogs may energetically greet others, a behaviour biologists call ‘rally’. One runs up towards another with its head held low, mouth agape and ears folded back. When they are nose to nose, the approaching dog licks and pokes the corner of the other’s mouth as if begging, while making high-pitched whines, whimpers and twitters. Biologists thought this repertoire was a preamble to hunting.
Researchers from the US, the UK and Australia studied the behaviour of five packs of 49 dogs at Moremi Game Reserve in the Okavango Delta, Botswana, for a year. They located the packs using radio collars and identified each dog by its unique pattern of brown and black blotches. By viewing video recordings, they noted which animal started a rally and how the others responded.
They observed the packs don’t set off on a hunt after every greeting ceremony. Sometimes, after a rally, the whole pack settled back for another rest. If the rally itself wasn’t enough to shake the dogs’ inertia, what could?
Amongst the wild dogs’ vocal chatter, the biologists identified “audible, abrupt exhalation of air through the nose, or ‘sneezes’.” After one sneezed, the whole pack appeared to catch the contagion. More than the rallies, the research team realised, the number of sneezes predicted whether the pack set off to hunt.
“[We] couldn’t quite believe it when our analyses confirmed our suspicions,” Neil Jordan, University of New South Wales, Australia, and one of the coauthors, said in a press release. “The sneeze acts like a type of voting system.”
But the researchers couldn’t definitely prove that sneezing was the signal to move. They couldn’t see through the thick grass if the canids voted by some other means. Perhaps they sneezed to shake off their lethargy and clear their nasal tracts so they can pick up scent trails during the hunt. Since the chances of the pack departing on a hunt were higher after a communal bout of sharp exhalations of air, it may well be a way of reaching a quorum.
“Playback experiments would be needed to fully disentangle this audible part to be the negotiating mechanism from any other behavioural display within the rallies,” Marta Manser, University of Zurich, Switzerland, who wasn’t involved in this study, told The Wire.
Other canids have a similar repertoire of sharp exhalations: foxes ‘pant’ as an invitation to play, coyotes ‘huff’ in alarm and dingoes ‘snuff’ when nervous. But unlike expressions of fear and anxiousness, the wild dog sneeze doesn’t disturb others in its pack. They don’t look askance or startled at the sneezer.
The researchers say they didn’t investigate what was critical to pull off the vote: the number of sneezes or number of sneezing dogs. Would a restless dog sneezing a few times count as much as several dogs sneezing at once? “Depending on the contribution of a single or several individuals, the decision-making process would then reflect rather different mechanisms,” says Manser.
Other social carnivores like meerkats use a similar decision-making process. But there’s a key difference between the species: in African wild dogs, not every vote is equal. Voting is rigged in favour of higher ranking members.
If the dominant pair didn’t initiate sneezing, “more sneezes were needed – approximately 10 – before the pack would move off,” Reena Walker, Brown University, Rhode Island, and the lead author said.
But when the alpha dogs give the signal, they need a minimum of only three sneezes to set their packs trotting.
Why do dominant dogs find it easier to rouse the pack than others? And why don’t meerkats behave the same way?
“The difference in the two species may be explained by their diets,” says Manser. “Meerkats search for their own prey and don’t share food with each other, while African wild dogs hunt for a single prey to feed them all.”
Meerkats aren’t cooperative hunters like African wild dogs. They call ‘shall we move’ when they are grubbing for beetles and scorpions in tall grass out of sight of each other. By the time one makes the first call, they’ve hunted out the area and it’s time to move. So it doesn’t matter who takes that call since there are fewer delectable grubs to pick anyway. But wild dogs call to decide whether to stay put and laze some more or go out and bring down a gazelle. Perhaps the different contexts play a role as well.
Instead of sneezing during the rallies, the wild dog pack seems to be on the move already when its members sneeze, as the videos above show. “We observed a peak of sneezing in the last minute of rallies, right before departure,” Walker told The Wire. “We defined departure as directed movement of the pack 20 metres away from resting sites. Sneezing occurs throughout the active, social parts of rallies as well as through quieter part of rallies right before the dogs move off.”
Irrespective of who initiated the vote to hunt, once they are on the move, the dominant ones lead.
“I look forward to learn more about why sneezing may come into play rather than an obvious vocalisation in African wild dogs,” says Manser.
Although other authors described the pre-hunt greeting behaviour in these canids, the research team writes that this is the first study to “quantitatively assess behaviour and decision-making processes in African wild dog pre-departure rallies.”
So if a sneeze says, ‘Yes, let’s go hunting’, what is African wild dog for ‘Let’s go north’?
The research was published in the journal Proceedings of the Royal Society B on September 6, 2017.
Janaki Lenin is the author of My Husband and Other Animals. She lives in a forest with snake-man Rom Whitaker and tweets at @janakilenin.