Small mammals or micromammals are a subdivision of

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s based on their body mass and size. Different values have been used as the upper limit. The

International Biological Program The International Biological Program (IBP) was an effort between 1964 and 1974 to coordinate large-scale ecological and environmental studies. Organized in the wake of the successful International Geophysical Year (IGY) of 1957–1958, the Interna ...

me has defined small mammals as species weighing up to 5 kg. Alternatively, the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

(IUCN) groups the orders of

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

tree shrew The treeshrews (also called tree shrews or banxrings) are small mammals native to the tropical forests of South and Southeast Asia. They make up the entire Order (biology), order Scandentia (from Latin ''scandere'', "to climb"), which split into ...

s and

eulipotyphla Eulipotyphla (, from '' eu-'' + '' Lipotyphla'', meaning truly lacking blind gut; sometimes called true insectivores) is an order of mammals comprising the Erinaceidae ( hedgehogs and gymnures); Solenodontidae (solenodons); Talpidae ( mole ...

ns (insectivores) together under the term small mammals. A significant majority of mammal species falls into the category of small mammals. They are found in a great range of habitats and climate zones.

Characteristics

Many small mammals have a short livespan and high fertility rate, resulting in a comparatively high variability in genetic composition. Their size leads to a reduced energy need for movement, but a high energy requirement for maintaining body temperature. This results in a high rate of food intake, using a wide range food sources. Their small size, together with frequently nocturnal or

crepuscular In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal (active during dawn), vespertine (biology), vespertine/vespertinal (active during dusk), or both. This is distinguished from diurnalit ...

activity, provide some protection against predators.

List of species

Eulipotyphlans

Rodents

Tree shrews

The tree shrews (family Tupaiidae) are non-rodent, primate-like animals and are classified into the order Scandentia. They are subdivided into two subfamilies: the diurnal subfamily Tupaiinae with five genera (Tupaia, Anathana, Dendrogale, Lyonogale, Urogale) and the nocturnal subfamily Ptilocercinae with a single genus, pen-tailed tree shrew Ptilocercus

Research and conservation

The SSC Small Mammal Specialist Group (SMSG) of the IUCN "serves as the global authority on the world's small mammals" both with regard to research as well as conservation efforts.

References

Cao, J., Li, J. S. Y., & Chow, P. (2003, May 6). The tree shrews: adjuncts and alternatives to primates as models for biomedical research. Wiley Online Library. https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1600-0684.2003.00022.x Mammals {{Mammal-stub