In a video for its “Pets - Wild at Heart” series, BBC One gives viewers an inside look at a golden hamster’s chubby cheeks—literally. As hamster owners and enthusiasts know, these tiny critters can stuff a seemingly impossible amount of food into their cheeks, which they’ll save for later (you know, in case of emergencies). But how is it possible? 

The hamster, it turns out, is the rodent version of the Weasleys’ bewitched tent in Harry Potter or Doctor Who's TARDIS: It’s bigger on the inside than it appears from the outside. As the X-rays in this video show, hamsters’ cheek pockets extend all the way to their hips!