GREENVILLE, S.C. (AP) — Utility officials say a snake caused a power outage that left more than 4,000 customers without electricity in northwestern South Carolina.

Duke Energy spokesman Ryan Mosier told media outlets a snake that crawled into a substation disrupted service and left Greenville County residents in the dark about 5 a.m. Wednesday.

It took about 90 minutes to completely restore service.

Mosier says the utility constantly works to improve its barriers to prevent snakes, squirrels and birds from crawling into the electrical equipment at substations and causing outages.

But he says it's not uncommon, especially this time of year. Mosier said small animals remain a big reason for power outages.