In the video, a small mouse is seen inside a cage. The mouse is black in color and has a white belly. The cage is made of metal bars and the floor is covered with hay. The mouse is standing on its hind legs and is sniffing a glass jar that is placed on the floor of the cage. The jar is filled with a white substance, which could be some kind of food or water. The mouse seems to be curious about the jar and is inspecting it closely. The video does not show any other objects or animals in the cage.