“She put her nose on my lower belly and sniffed so intently that I thought I spilled something on my clothes,” Herfel told the Milwaukee Journal Sentinel. “She did it a second and then a third time. After the third time, Sierra went and hid. I mean hid!” Herfel decided to make an appointment with a gynecologist, who told her she had an ovarian cyst and sent her home with pain medication.

But when Herfel came home, her dog acted strangely again, rolling up in a tight ball inside a closet. Unnerved, she decided to get a second opinion. Several weeks later, a gynecologist confirmed she had stage III ovarian cancer. Herfel underwent a hysterectomy and had chemotherapy, but that wasn’t the end of the story.