1930s—U.S. production of canned cat food 1930s—Spaying and neutering of cats and dogs introduced 1940s—Meat shortage Limited meat rations in the 1940s leads to the development of dry food, which made use of livestock scraps and fish. Dry food eventually becomes the majority of cat food produced and purchased. 1947—Invention of kitty litter by Ed Lowe. Before that, people used ashes, dirt, or sand, but most people let their cats “go” outside.
