Which is larger, a rat or a hamster? - briefly
Rats exceed hamsters in size; adult rats usually weigh 200–500 g and measure 20–30 cm in body length, whereas hamsters typically weigh 30–150 g and are 7–15 cm long.
Which is larger, a rat or a hamster? - in detail
Rats generally exceed hamsters in both length and mass. Adult brown rats (Rattus norvegicus) typically reach a head‑body length of 20–25 cm, with a tail adding another 15–20 cm. Their body weight ranges from 250 g to 500 g, and some individuals approach 600 g. In contrast, the most common domestic hamster (Mesocricetus auratus) attains a head‑body length of 12–15 cm and a tail of less than 2 cm. Adult weight usually falls between 80 g and 150 g; dwarf species such as Phodopus sungorus are even smaller, rarely exceeding 30 g.
Key dimensions:
- Body length (excluding tail)
- Rat: 20–25 cm
- Hamster: 12–15 cm (larger species) / 6–10 cm (dwarf species)
- Tail length
- Rat: 15–20 cm, proportionally long
- Hamster: ≤2 cm, often vestigial
- Typical adult weight
- Rat: 250–500 g (up to 600 g)
- Hamster: 80–150 g (dwarf ≤30 g)
Species variation influences size. Wild Norway rats can be larger than laboratory strains, while some hamster breeds (e.g., Syrian) approach the upper size range for hamsters but remain considerably smaller than the average rat. Muscular development, diet, and environment cause modest fluctuations, yet the disparity in maximum dimensions persists across populations.
When assessing size for practical purposes—housing, handling, or research—rats require more spacious enclosures and stronger containment methods due to their greater length and strength. Hamsters, being compact, fit comfortably in smaller cages and present lower risk of escape.
In summary, the rodent with the greater overall dimensions and mass is the rat.