Which is larger, a rat or a shrew? - briefly
A rat typically measures 20–30 cm in body length and weighs 150–300 g, whereas a shrew averages 5–10 cm and 2–20 g. Consequently, the rodent is considerably larger than the insectivore.
Which is larger, a rat or a shrew? - in detail
Rats typically exceed shrews in both length and mass. The most widespread rat, the brown (Norwegian) rat (Rattus norvegicus), reaches a head‑body length of 20–25 cm (8–10 in) and a tail of a similar size. Adult weight ranges from 250 g to 500 g (0.55–1.1 lb). Larger species, such as the black rat (Rattus rattus), attain comparable dimensions, with body lengths up to 22 cm (9 in) and weights of 150–300 g (0.33–0.66 lb).
Shrews are markedly smaller. The common shrew (Sorex araneus) measures 5–8 cm (2–3 in) in head‑body length, with a tail of 3–5 cm (1–2 in). Adult mass falls between 5 g and 12 g (0.18–0.42 oz). Even the largest shrew species, the American water shrew (Sorex palustris), does not exceed 12 cm (5 in) in body length and weighs under 20 g (0.7 oz).
Key comparative points:
- Length: Rats are roughly three to four times longer than shrews.
- Weight: Rats are 10–50 times heavier, depending on species.
- Body proportion: Rats possess a robust, elongated body with a long, hairless tail; shrews have a slender body, short tail, and dense fur.
- Ecological role: Size differences reflect distinct niches—rats are omnivorous opportunists, while shrews are insectivorous predators of invertebrates.
Consequently, any rat specimen will be larger than any shrew specimen across the spectrum of common species.