Waltham and Watertown faced widespread power outages on Thursday when a squirrel came in contact with Eversource Energy electrical equipment.

Eversource Massachusetts spokesperson Rhiannon D’Angelo told the Waltham Patch that that the outage affected more than 4,000 customers, although much of the power was restored within an hour of the outage.

“In May alone, squirrels were responsible for nearly forty separate outages in Western Mass,” Eversource MA wrote on Facebook on June 23. “This issue isn’t new to utilities by any means, and we employ a number of techniques and deterrents from squirrel guards to automated switching to combat these constantly climbing creatures.”

A Jan. 12 blog post from the Washington Post said that the American Public Power Association, a group that represents municipal electric utilities, told the Post that squirrels are the most frequent cause of power outages in the U.S., although it also noted that squirrel-induced outages typically affect fewer people than outages caused by storms.

Meanwhile, the Brookings Institution, a think tank, wrote on its website that “squirrels have taken down the power grid more times than the zero times that hackers have.”

A somewhat tongue-in-cheek website with the domain name “CyberSquirel1.com” keeps a detailed list of all electrical outages caused by squirrels since 1987. However, the map describes these incidents as “unclassified Cyber Squirrel Operations that have been released to the public that we have been able to confirm” and refers to the cause of these outages as “cyber war operatives.”

For the record, squirrels outnumber other countries in causing successful United States electrical outages 785 to zero, according to CyberSquirel1.

—Abby Patkin