Order : EULIPOTYPHLA
Family : Soricidae
Species : many genera and species

Head-Body Length : up to 15 cm
Tail Length : up to 8 cm
Weight : up to 60 grams

Worldwide, around 400 species of shrew in 26 genera are recognised, and many species occur in Southeast Asia. They are found in a range of habitats from the lowlands to montane areas.

Shrews are amongst the smallest mammals in the world, along with some insectivorous bats. The largest species of shrew is the House Shrew Suncus murinus which can weigh up to 60 grams, and the smallest is the Pygmy White-toothed Shrew Suncus etruscus (or Etruscan Shrew) which weighs just 2.5 grams. Both of these occur in Southeast Asia.

Shrews have short legs, short fur, small eyes and a pointed snout, often with long whiskers. They are mainly nocturnal and terrestrial, however water shrews have adapted to a semi-aquatic existence in forest streams.

Different species may feed on a wide range of invertebrates (insects, worms) and plant matter (nuts, seeds). Some species are venomous, and use toxins to kill their small prey.

Although shrews bear some external similarity to mice, the two groups are not closely related and their dentition is quite different. Shrews bear a single incisor on the upper jaw, whereas mice and other rodents have pairs of incisors on both the upper and lower jaws. Shrews also bear a large number of unicuspid teeth (i.e. teeth which bear a single, sharp point): this is the case for their canines and most premolars. Tooth colour can help distinguish between different groups of shrews: for example shrews of the genus Crocidura, are also known as white-toothed shrews.

True shrews are unrelated to treeshrews, which are much larger: a widespread and typical example of treeshrew is the Common Treeshrew Tupaia glis.

Shrews occur throughout Southeast Asia: Francis (2008) lists 26 species of 9 genera for mainland Southeast Asia alone. Phillipps & Phillipps (2016) list 8 species for the island of Borneo, and many other species occur in the rest of insular Southeast Asia.

Figs 1 and 2 : A Crocidura shrew photographed in montane habitat at 1100 metres elevation at Maxwell Hill (Bukit Larut), Peninsular Malaysia. This is most likely Crocidura monticola (Sunda Shrew), a species trapped a number of times in the area by Hasmahzaiti Omar, during her thesis study (Hasmahzaiti Omar et al, 2013). Photos thanks to Serin Subaraj.

Fig 3 : A House Shrew Suncus murinus peers out from a crevice amongst woody debris in a secondary forest on the island of Sentosa, Singapore.


References :

Francis, C.M. 2019. A Field Guide to the Mammals of South-east Asia. Second Edition. New Holland. 416 pp.

Hasmahzaiti Omar, Rosli Hashim, Subha Bhassu & Manuel Ruedi.  (2013). Morphological and genetic relationships of the Crocidura monticola species complex (Soricidae: Crocidurinae) in Sundaland. Mammalian Biology, 78(6), 446-454.

Phillipps Q. & Phillipps K. (2016). Phillipps’ Field Guide to the Mammals of Borneo and Their Ecology: Sabah, Sarawak, Brunei, and Kalimantan. Second Edition. John Beaufoy Publishing. 400 pp.