Ever wondered what the smallest mammals in the world are?
Humans are a whole lot smaller than the largest animals on the planet, but we’re still quite a big species, dwarfing most living creatures. There are literally millions of animal species smaller than humans, and many of those species are mammals.
- Not sure what a mammal is?
Mammals are warm-blooded vertebrate animals that have hair or fur, with the females giving birth to live young that they feed by secreting milk. Need more mammal info?
Whilst there’s a school of thought that suggests ‘bigger is better’, for wildlife this isn’t always the case. Small animals need fewer resources to survive and have plenty of options for hiding places to escape from predators, or hibernate, without having to rely on camouflage alone. Smaller mammals are also able to make their petite frames work to their advantage by climbing across small branches while hunting.
Below we’ve picked out 15 of the smallest mammals in the world. We’ve tried to provide a variety of different mammal species and genus, so rather than listing all species of pygmy possums, for example, we’ve listed only one, to leave room on the list for lots of other tiny mammals!
With this in mind, here’s our pick of the world’s smallest mammals:
Least weasel (Mustela nivalis)
180 millimeters long
Not only is the least weasel tiny – with the larger males growing up to 18 centimeters long – but as the smallest species of the Carnivora order, it holds the distinction of being the smallest carnivore in the world.
Widespread through the Northern Hemisphere, the last weasel also goes by the names of ‘little weasel’, ‘common weasel’, or simply ‘weasel’. They are as comfortable above ground as underground and are skilled hunters – regularly killing prey much larger than themselves, and storing the remains for another meal.
Philippine tarsier (Carlito syrichta)
165 millimeters long
The Philippine Tarsier lives in low lying dense forests in central and southern Philippines. Growing between 85 and 165 millimeters tall as full-grown adults the tarsier is one of the world’s smallest primates.
Pen-tailed tree shrew
130 millimeters long
Not to be confused with shrews or elephant shrews, tree shrews are a distinct group of mammals, and the pen-tailed shrew is the smallest of the lot, averaging 13 centimeters in length.
Aside from their usual diet of insects and small geckos, these mammals like to party, and have frequently been seen consuming fermented alcohol from the bertam palm. Apparently, pen-tailed tree shrews drink the equivalent of 12 beers a day without getting drunk!
Smallest monkey: Pygmy marmoset (Callitrichidae Cebuella)
130 millimeters long
Possibly the cutest animal on this list, the pygmy marmoset is officially the world’s smallest monkey. Excluding their tail, these South American monkeys have an average height of just 130 millimeters.
American shrew mole
120 millimeters long
The American shrew mole is one of the smallest mammals around and is the smallest species of mole in the world. At 12 centimeters long (plus tail) and 10 grams in weight, this mole has no external ears, and eyes so small they’re hardly visible.
Unlike other moles that spend most of their lives underground, the American shrew mole (also known as Gibb’s shrew mole) is often seen foraging for food above ground in its native northwestern United States and southwestern British Columbia. It also has a remarkable mole-skill of being able to climb bushes to hunt for insects!
Pink fairy armadillo (Chlamyphorus truncatus)
105 millimeters long
Pink fairy armadillo – or ‘pichiciegos’ are the smallest species of armadillo, averaging 105 millimeters in length. They are desert-adapted nocturnal burrowing animals, endemic to the desert and scrubby grasslands of central Argentina.
Pygmy possum (Burramyidae)
100 millimeters long
Maxing out at around 10 centimeters long, these tiny marsupials are found in varied areas of Australia and New Guinea, hanging around in trees by their tails.
Pygmy possums are nocturnal, and during the winter they hibernate by rolling into a tight ball, covering their eyes with their ears, and entering torpor. During hibernation the possum’s metabolism and body temperature reduce, and it takes nourishment from fat stored in its tail.
Madame Berthe’s Mouse Lemur (Microcebus berthae)
92 millimeters long
Madame Berthe’s mouse lemur takes the title of the world’s smallest primate, with an average body length of 92 millimeters and a weight of around 30 grams. This solitary nocturnal primate is endemic to Madagascar.
African pygmy mouse (Mus minutoides)
70 millimeters long
All mice are small, but the African pygmy mouse takes this to the next level. They range from 3cm to 7 cm in length and weigh as little as 3 grams. They’re so small that their main water source is not a river or stream, but dew that accumulates on tiny pebbles it stacks by its burrow entrance for that specific purpose. Tiny mouse but decent brain!
60 millimeters long
Another marsupial for this smallest mammals list, this time it’s the long-tailed planigale – the world’s smallest marsupial. Native to Australia, these mammals average 6 centimeters in length – including their tail – and 4.3 grams in weight.
They are strong nocturnal hunters, chasing down insects and young mammals almost as large as themselves. Their small size and body shape allow them to squeeze into tiny crevices to hide from predators, and their marsupial pouch faces towards the rear to keep it clean as the press themselves into minute hiding spaces and burrow through earth.
Smallest mammal (by weight): Etruscan shrew (Callitrichidae Cebuella)
58 millimeters long
Including their short tail an adult Etruscan shrew grows to an average of 58 millimeters. It’s a slightly longer mammal than the Kitti’s hog-nosed bat, but is smaller in weight. Eating up to 25 times a day due to their high metabolism, these tiny mammals are also distinguished by having the largest brain to body weight ratio of any animal in the world!
Baluchistan pygmy jerboa (Salpingotulus michaelis)
44 millimeters long
The dwarf three-toed jerboa also goes by the name Baluchistan pygmy jerboa, and is found in the harsh deserts of Pakistan and Afghanistan. They are the smallest known rodent, growing to 44 millimeters in length with relatively large hind legs, these creatures survive by burrowing under small bushes to feed on seeds and leaves.
Smallest mammal in the world: Kitti’s hog-nosed bat (Craseonycteris thonglongyai)
30 millimeters long
Averaging around 30 millimeters in length, the Kitti’s hog-nosed bat is officially the world’s smallest mammal – the same size as a bumblebee. Along with their tiny size, they can be recognised by their pig-like snouts and reddish-brown coats. This endangered species lives in groups of up to 100 in riverside limestone caves in Thailand and Myanmar.
And that’s your lot for our pick of the world’s smallest mammals. What do you think – did any of these tiny creatures surprise you? Or perhaps we’ve left out an obvious mammalian pick to add to the list.
Please join in and let us know your thoughts, or any experiences you have of the smallest mammals in the world in the comments section below!
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