The Oregon Humane Society in Portland explains, Silky the hamster is hairless due to a genetic mutation.
In a news release, OHS staffer Diana Gabaldon says that because Silky "isn't fluffy like a normal hamster," she gets cold easily.
Silky "does need to be kept in a heated environment, especially during the winter, and have a higher protein diet to keep her warm," Gabaldon said.
But recently, on a particularly cold day, despite a heated habitat and higher protein diet, Silky was found "huddled in the corner of her cage," the news release said.
So, OHS Animal Care Technician Selene Mejia gave her a custom-sized sweater "to help her stay cozy" on especially cold days.
Read the full story from ABC News.