The World’s Smallest Mammals

Published November 7, 2012
Updated November 7, 2023

Some of the tiniest, cutest, and most fascinating creatures on the planet -- a look at the world's smallest mammals!

The World’s Smallest Mammals: Kitti’s Hog-Nosed Bat

Depending on whether you measure by weight or size, Kitti’s Hog-nosed Bat (aka the Bumblebee Bat) is one of the two top contenders for world’s smallest mammal. At an average of 2g (0.071oz), this diminutive species is found in limestone caves along rivers in western Thailand and southeast Burma.

While most cave-dwelling bats huddle together in large groups on cave walls and ceilings, these bats prefer their own space and tend to spread out when resting. They also reproduce very slowly and are particularly vulnerable to disturbances in their habitat.

Etruscan Pygmy Shrew

Losing out to bats in size, the Etruscan shrew, weighing in at 1.8g (0.063oz), can claim the world’s smallest mammal by weight. Like most shrews, the Etruscan is a voracious predator that uses whisker-guided attacks to eat almost twice its own weight in grubs, worms and insects on a daily basis. It needs all this food to fuel a hyperactive metabolism that requires their teeny tiny hearts to beat 1511 times every second. 

Savannah Cox
Savannah Cox holds a Master's in International Affairs from The New School as well as a PhD from the University of California, Berkeley, and now serves as an Assistant Professor at the University of Sheffield. Her work as a writer has also appeared on DNAinfo.
John Kuroski
John Kuroski is the editorial director of All That's Interesting. He graduated from New York University with a degree in history, earning a place in the Phi Alpha Theta honor society for history students. An editor at All That's Interesting since 2015, his areas of interest include modern history and true crime.
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Cox, Savannah. "The World’s Smallest Mammals.", November 7, 2012, Accessed May 21, 2024.