Bears behave like friendly dogs due to a strange brain condition

A mysterious disease turns some friendly and fearless black bears, among other strange symptoms.

Researchers believe the disease, which appears to affect young bears for about a year, is a type of encephalitis, which means inflammation of the brain, according to a statement from the California Department of Fish and Wildlife late last month. Since 2014, a handful of bears from Nevada and California have shown signs of the condition, and four bears from California have been confirmed to have it in the last year.

“The first bear I personally rescued was diagnosed with encephalitis in March 2018,” Ann Bryant of Bear Education Aversion Response told Live Science. “He went into a school and into a classroom where he sat among the children, behaving very much like a friendly dog.”

Encephalitis has other serious effects on bears, including tremors, nods and seizures. Affected bears also tend to be severely underweight. A bear, seen in February, picking an apple and eating it among people on a patio, weighed only 21 kilograms when it should have weighed about 80 kilograms. She was also covered in ticks, walked strangely, and was eventually euthanized.

It is not yet clear exactly what causes inflammation of the brain. But while studying the phenomenon, scientists have identified five previously unknown viruses in affected bears.

These viruses are believed to pose no risk to humans, Jamie Sherman, a veterinarian at the University of California, One Health Institute in Davis, told Sacramento Bee.

Bears suffering from encephalitis should usually be euthanized. Their symptoms make them unmanageable to survive in the wild, and those placed in zoos or sanctuaries can become a “huge burden” due to the lifelong medical care they will need, wildlife veterinarian Brandon Munk said in a CFDW statement.

However, two bears with neurological problems in recent years have managed to find new homes. One, now named Elinor, was brought to the Orange County Zoo. The other bear, which went viral after being caught on camera sniffing a snowboarder and now named Benji, lives at the Ramona Wildlife Center of the San Diego Humane Society. Last month, Benji celebrated his third birthday with a cake made of fruit and mashed potatoes.