Expert: John Locke - 7/17/2007

Question
hello Mr.John...i would like to ask you that why rodents and mice are used so commonly for scientific experiments and not others???

Answer
Thanks for using AllExperts, and I'd be happy to answer your question.

Before I can answer it directly, though, I need to describe a particular way that scientists test their hypotheses--through the use of models. Many experiments focus on things that are simply too big, too complex, or too hard to test directly (the weather, ocean currents, and the Solar System, for example). That doesn't mean that we can't carry out any experiments, though--we just need to make things a bit simpler, by using a model instead of the real thing. A model, of course, is a representation of another thing that's usually a little simpler and easier to work with than the thing itself. Science requires the use of models all the time--a mathematical equation can be a model for how object interact in the physical world. A car can be tested for aerodynamics by running an air stream over a miniature version of that car. And, in the example you're referring to, a rodent can stand in for a human being as a model.

Sometimes the tests to be conducted are simply too dangerous for people to undergo without animals experiencing them first (this is a very common reason for using animals in medical research: new drugs are given to animals before people are ever allowed to try them). Sometimes the tests are simple enough that people aren't needed--you don't have to send people through a maze, for instance; rats do just fine. Often, scientists simply can't find enough volunteers willing to be part of an experiment, so they scale it down or change it in some way so that animals can be used to test the same basic concept.

Now I can tell you why some animals are used much more for research than others: scientists always like to use animals are easy to work with, well-understood, and can stand in for a lot of other animals. Rats and mice are very easy to work with, and we understand their anatomy, physiology, and behavior very well. They can also be used in place of dogs, cats, people, etc., pretty reliably: the results not only tell you about the rodents themselves, but also about the animals they're meant to represent. They're not the only common model organisms, though; dogs have a pancreas very similar to that in people, so canines get used in the study of diabetes. Pigs have hearts very similar to people, so they get used in the study of cardiac problems.

Ultimately, though, working with a model is not the same as working with the real thing. Even a very good model will behave a little differently from the thing you're trying to investigate, and that's always something to keep in mind when animals are used in scientific research.