What animal is smaller than a mouse? - briefly
Animals smaller than a typical house mouse include the bumblebee bat (the world’s smallest mammal), the Etruscan shrew, and dwarf hamster species.
What animal is smaller than a mouse? - in detail
Mice typically weigh between 15 and 30 g and measure 6–10 cm in body length. Several vertebrate and invertebrate species fall below these dimensions.
The smallest mammals include the bumblebee bat (Craseonycteris thonglongyai), weighing about 2 g and measuring 3 cm from head to tail. The Etruscan shrew (Suncus etruscus) averages 1.8 g and reaches a length of 5 cm, making it lighter and slightly longer than a mouse but still markedly smaller in mass.
Among birds, the bee hummingbird (Mellisuga helenae) records a weight of 1.6–2 g and a total length of 5–6 cm, positioning it well beneath typical rodent size.
Amphibians such as the Paedophryne amauensis, a frog species from Papua New Guinea, measures 7.7 mm in snout‑vent length and weighs less than 0.1 g, representing an extreme reduction in size relative to rodents.
In the fish category, Paedocypris progenetica reaches a maximum length of 7.9 mm and a weight of approximately 0.01 g, placing it among the tiniest vertebrates known.
Numerous insects also qualify. For instance:
- Fairyflies (family Mymaridae) include species like Dicopomorpha echmepterygis, males measuring 0.139 mm in length.
- The parasitoid wasp Trichogramma species are 0.2–0.3 mm long.
- The dwarf beetle Scydosella musawasensis attains a length of 0.30 mm.
These examples illustrate the range of organisms whose body mass and dimensions are substantially less than those of a common house mouse, spanning mammals, birds, amphibians, fish, and arthropods.