A flock of sheep in China has been filmed walking continuously in a circle for 12 days, baffling people across the globe, but now the mystery may have been solved.
The phenomenon, captured on video and posted to Twitter by Chinese state-run outlet People’s Daily, shows the sheep walking in a circle on a farm in Inner Mongolia, North China. Most, but not all, of the animals in the pen, can be seen engaging in the behavior.
The great sheep mystery! Hundreds of sheep walk in a circle for over 10 days in N China's Inner Mongolia. The sheep are healthy and the reason for the weird behavior is still a mystery. pic.twitter.com/8Jg7yOPmGK
— People's Daily, China (@PDChina) November 16, 2022
Sheep are well known to mimic behaviors of others in the flock. This is due to social instinct that tells them to follow the animal in front of them to evade predators and protect individuals in the group. However, it is particularly unusual for them to move in such synchronized movements for a prolonged period of time.
A potential explanation has been shared by Matt Bell, a professor and director at the Department of Agriculture at Hartpury University, in Gloucester, England.
“It looks like the sheep are in the pen for long periods, and this might lead to stereotypic behavior, with the repeated circling due to frustration about being in the pen and limited [as to where they can go]. This is not good. Then the other sheep join as they are flock animals and bond or join their friends,” Bell told Newsweek.
The sheep had been displaying this behavior since November 4, the Chinese news outlet reported. The animals were moving like this for at least 12 days, and it is unclear whether they stopped at intervals to eat or drink or whether the sheep are continuing their movements as of November 21.
The owner of the farm, identified as Ms. Miao, told local news outlets that there were only a few sheep displaying the behavior at first, but gradually the whole flock started following suit, the U.K. newspaper Metro reported.
Ms Miao owns sheep that are kept in 34 pens, but only one flock of sheep, in one pen, have been acting strangely.
Some experts have put the behavior down to listeriosis—a bacterial disease also known as ‘circling disease.’
The bacteria can infect sheep through the soil, food and feces, with circling just one symptom of the disease. Others include lack of appetite, depression, and lack of coordination.
While listeriosis can cause circling in livestock, recovery is rare, and its effects are fast moving.
The disease usually causes death within two days, so it does not explain how the sheep have continued walking in circles for so long.
The Listeria monocytogenes bacteria causes an asymmetrical infection in the brain stem, which can result in one side of the animal’s face becoming paralysed and incessant circling, earning it the nickname “circling disease”.
However, there are a number of giveaways that circling disease is not behind the behaviour seen in the video, according to Andrew Fisher, a professor of cattle and sheep production medicine at the University of Melbourne.
“They’d show a variety of circling and other neurological conditions and they’d get quite sick — some would die,” Professor Fisher said.
“The way it usually manifests is not in half the flock — it’s sort of between 1 and 10 per cent might be affected.”
Animals suffering from listeriosis also don’t move in concentric circles, but loll in their own pattern.
If it quacks like a sheep
Professor Fisher said there was an outside chance that the animals had developed a behavioural response to being kept in a small confined area.
He said that in the past when zoo animals were kept in small enclosures with little stimulus, they could exhibit “stereotypical pacing”.
“In that scenario, they have a very defined or consistent, unvarying pathway.”
However, he said while we can’t say for certain, there’s a more likely explanation.
“One suspects there’s more going on behind the video that we don’t see,” he said.
Emma Doyle, a livestock expert and lecturer at the University of New England’s School of Environmental and Rural Science, put it more bluntly.
“As soon as I looked at it, I thought, ‘I’ve never seen sheep act like that,'” Dr Doyle said.
“It seems a bit dodgy. It looks sort of set up where they’ve put something in the middle to stop them going in.”
Dr Doyle said it would be highly unlikely for sheep to form such a perfect, concentric shape, without some sort of interference.
The other, bigger problem though is that several media sources reported the animals were doing circles “non-stop” for 12 days.
“They’re not going to go 12 days without water and food,” Dr Doyle said.
The implication then is that the animals are leaving the circle for food and water before rejoining.
“It’s very mysterious and at first look, a little hoax-y to me,” Dr Doyle said.
“If it’s real then I stand to be corrected.”