Which statement best describes the share of cats and dogs in medical research?

• A. Fewer than one percent
• B. More than ninety percent
• C. About one-half
• D. None

Answer: (A)

The share of cats and dogs in medical research is very small, typically fewer than one percent. In practice, the vast majority of animals used are mice and rats, because they are inexpensive to breed and house, have short lifespans, and researchers have long-established models and techniques for them. Dogs and cats are used only for specific studies where their physiology or behavior provides a unique advantage, and they are subject to stricter ethical and regulatory scrutiny. This combination keeps their numbers low relative to other species. So, the best description is that cats and dogs together account for fewer than one percent of animals used in biomedical research.