New Bedford, Mass. (AP) — A Massachusetts zoo is monitoring the health of one of its elephants closely after it was exposed to extreme cold during last week's snowstorm.

Officials at Buttonwood Zoo in New Bedford say Ruth, a 55-year-old Asian elephant, escaped from her heated barn sometime between 5 a.m. and 7 a.m. Friday at the height of the storm with temperatures around zero. Someone forgot to padlock the door.

Zoo Director Keith Lovett tells The Standard-Times she was brought inside as soon as staff noticed and warmed with hot blankets and heaters.

The elephant is on antibiotics as a precaution and is being monitored for hypothermia and frost bite by a vet. Lovett says the effects of extreme cold can sometimes show up days later, but so far Ruth seems fine.