Why are rodents commonly used in scientific research?

• A. They have a short lifespan, are easy to breed, and have biological similarities to humans.
• B. They are cheaper than primates only.
• C. They do not require housing.
• D. They are immune to most diseases.

Answer: (A)

Rodents are favored because they combine practical handling traits with biology that is informative for human health. Their short lifespans and rapid generation times let researchers observe disease progression, aging, and treatment effects across generations in a feasible timeframe. Easy breeding supports large, well-controlled groups and the use of standardized strains, which improves reproducibility and enables precise genetic studies. Importantly, as mammals they share many physiological and genetic pathways with humans, so discoveries about disease mechanisms and drug effects often translate to humans; there is also a long-established toolkit of genetic manipulation, housing guidelines, and validated experimental protocols. The other options don’t fit because housing is a basic requirement, they are not immune to most diseases, and while costs matter, they’re not the primary reason for their widespread use.