Which animal weighs less than a rat? - briefly
A house mouse (≈ 20 g) and a common shrew (≈ 5–15 g) both weigh less than a typical laboratory rat (≈ 250 g). Small birds such as a sparrow (≈ 30 g) also fall below the rat’s mass.
Which animal weighs less than a rat? - in detail
A common laboratory rat typically weighs between 150 g and 300 g. Numerous vertebrates and invertebrates fall below this mass range.
- House mouse (Mus musculus) – adult weight 15 g to 30 g.
- Common shrew (Sorex araneus) – body mass 5 g to 14 g.
- European robin (Erithacus rubecula) – average weight 16 g to 22 g.
- House sparrow (Passer domesticus) – 24 g to 40 g.
- Guppy (Poecilia reticulata) – mature individuals 2 g to 4 g.
- Honeybee (Apis mellifera) – worker weight about 0.1 g.
- Ant species (e.g., Lasius niger) – individual mass 1 mg to 5 mg.
These species consistently weigh less than a standard rat, with the smallest insects measuring only a fraction of a gram. Their physiological adaptations, such as high metabolic rates in shrews and efficient flight in small birds, permit survival at these lower body masses.