Cheese Chasers (1951)

Continuity mistake: When we first see the cheese where Hubie and Bertie have been eating from, there are two holes and by the left hole there are pieces of cheese. When Hubie emerges from the hole, the pieces have disappeared.

Hubie: Bert, an average mouse eats 12 pounds of cheese in a lifetime. I figure tonight we've lived 2000 years.