Mystery of Sheep Walking in Circle in China for 12 Days Potentially Solved

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.

Flock of sheep
A stock photo shows a flock of sheep. The farm animals in Inner Mongolia in North China were filmed walking around in a circle for days. Laurinson Crusoe/Getty

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.