Which species has a lifespan range that begins at 18 months?

• A. Mice
• B. Rats
• C. Gerbils
• D. Hamsters

Answer: (D)

Understanding species-specific lifespans is essential for planning studies and care. Each of these rodents has a typical range of life expectancy used in lab and pet settings, with the lower end indicating the minimum age at which individuals are commonly observed to live under normal conditions. Hamsters are described in many references as having a lifespan range that starts around 18 months (about 1.5 years), making 18 months the lower bound for that species. In contrast, mice are frequently listed with a lower bound closer to 12 months, and rats and gerbils are often given minimums around 24 months. So, when the question asks which species has a lifespan range that begins at 18 months, the hamster best fits that starting point, aligning with typical reference data. This distinction helps explain why the hamster is the correct choice in this context.