In the United States, amphibians (frogs, salamanders, etc.), fish, birds, mice, and rats are not defined as animals under animal experimentation guidelines, and thus researchers don’t need explicit permission to test on these living, breathing, pain-feeling beings. That’s not to say that animals like dogs, cats, pigs, and monkeys are safe, it just means that mice and rats are often tested on first to see a drug or a cosmetic’s effects, before moving onto larger animals that are considered more “human-like” creatures.