Cats love to chew on mice, so why not feed them meals with delicious rodent flavoring? Because, according to Shaun Belongie, the national brand manager for cat food company Friskies, the FDA says you can’t. It holds pet food to the same sanitation and safety standards as it does human food, approving ingredients it deems appropriate, and necessary, for an animal’s diet. Rodents aren’t sanctioned to be grown as a food source in the United States, and the Department of Agriculture doesn’t have an official inspection procedure for mice. So while fish are a go, mice are a no.

This story originally appeared in the September 2014 issue of mental_floss magazine. Subscribe to our print edition here, and our iPad edition here.