What percentage range do rodents constitute among animals used in biomedical research?

• A. 70-80%
• B. 90-95%
• C. 10-20%
• D. 30-40%

Answer: (B)

Rodents occupy the vast majority of animals used in biomedical research. Mice and rats are favored because they are small, inexpensive to house and breed, have short generation times, and there are extensive genetic tools and well‑characterized strains available. This combination makes large-scale studies in rodents highly practical and cost‑effective, so their share is typically around 90 to 95 percent. The remaining animals—such as rabbits, dogs, pigs, and nonhuman primates—comprise a comparatively small portion, which is why the overall figure for rodents lands in the high range. The lower percentage options would imply a much smaller role for rodents than what is commonly seen in research, which is not consistent with standard usage patterns.