11 Smallest Animals of Their Kind

From mini monkeys and diminutive deer to itty-bitty bats, these are some of the animal kingdom’s most minuscule members.

portrait of a pygmy marmoset in natural habitat
Portrait of a pygmy marmoset in natural habitat. Anolis01 / Getty Images

The world is filled with big things and the world is filled with little things. And while the big things boast magnitude and majesty, the little things ... well the little things boast an unwavering ability to elicit coos and squeals from us humans. As a species, we're hard-wired to fall for the cute and the little – an evolutionary guarantee that we'll take care of our babies. Which can make it hard to resist all the rest of the planet's smallest creatures as well. Consider the following.

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1. Smallest Primate: Madame Berthe's Mouse Lemur

credit: Melanie Dammhahn

Named after the conservationist and primatologist Berthe Rakotosamimanana of Madagascar, Microcebus berthae is the smallest living primate known to us. Found mainly in western Madagascar, they ring in at a mere 3.6 inches in length on average and weigh just over an ounce.

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2. Smallest Deer: Northern Pudú

credit: Julie Larsen Maher/WCS

There are two species of pudú, both hailing from South America – the Southern pudú, like the one pictured above, reaches a petite height of 14 to 18 inches at the shoulders, while its even more diminutive cousin, the Northern pudú, barely reaches 14 inches. Weighing in at the 7- to 13-pound range, they're about as heavy as a housecat!

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3. Smallest Bird: Bee Hummingbird

credit: charlesjsharp/Wikimedia

The bee hummingbird of Cuba didn't get its name for nothing; at a wee two inches long and less than 2 grams in weight, it is the smallest bird in the world. Theoretically, 16 of them could be mailed first class using a single stamp.

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4. Smallest Monkey: Pygmy Marmoset

credit: Jakub Koziol

Also known as known as the pocket monkey, little lion, and the dwarf monkey, the pygmy marmoset (Callithrix pygmaea) is considered the smallest monkey in the world. Weighing a lythe 4.20 ounces on average and measuring just over 5 inches, these South American forest monkeys could comfortably sleep in your hand.

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5. Smallest Frog: Paedophryne amauensis

credit: Wikimedia Commons

At 7.7 millimeters long, the fly-size Paedophryne amauensis from Papua New Guinea is not only the smallest frog in the world, but also the smallest vertebrate on the planet! Scientist believe that P. amauensis evolved into its wee size to facilitate a diet of tiny invertebrates that larger predators pass over.

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6. Smallest Mammal: Etruscan Shrew

credit: Trebol-a

While the Kitti's hog-nosed bat is the smallest mammal by skull size, sweet Suncus etruscus, the Etruscan shrew, is the smallest by mass. Weighing a teensy 1.8 grams and boasting a Lilliputian length of just an inch and a half, the shrewd shrew can nonetheless hunt prey the same size as itself.

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7. Smallest Bat: Kitti's Hog-Nosed Bat

credit: YouTube

Craseonycteris thonglongyai is very special. Not only is this bat the smallest bat in the world, but also the smallest mammal, as measured by skull size, in existence. Also known as a bumblebee bat, Craseonycteris thonglongyai lives in Mayanmar and Thailand – on average, they reach only about an inch in length.

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8. Smallest Seahorse: Denise's Pygmy Seahorse

credit: timsimages

At less than three-quarters of an inch in height, Hippocampus denise is like the tiniest miniature pony of the sea. Although so little in stature, these guys are big in skills; they are masters of camouflage and generally blend right in with the stems and polyps of their sea fan hosts.

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9. Smallest Antelope: Royal Antelope

credit: Mhx.andre

Of course there's a world's smallest antelope, and naturally, it's royal. Neotragus pygmaeus hails from West Africa and was first described by famed Swedish zoologist Carl Linnaeus in 1758. At a vertically-challenged 10 inches in height and weighing a scant five to six pounds, the regal cutie wears the crown of smallest ungulate and ruminant as well.

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10. Smallest Octopus: Octopus wolfi

Star-sucker Pygmy Octopus
AndamanSE / Getty Images

Well hello there teeny tiny octopus! The world's smallest octopus measures in at less than an inch, but that doesn't mean it's short of cunning – like any good octopus, it's known for its Houdini-like power of escape (take that, aquarium enthusiasts). Known since at least 1913, they can be found in waters up to 100 feet deep in the western Pacific.

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11. Smallest Chameleon: Brookesia Micra

credit: Frank Glaw

This little lizard from Madagascar is the smallest known chameleon and, no surprise, is among the smallest of known reptiles. Adult males only reach lengths of one inch from nose to tail. Aside from its remarkable size, B. micra is notable for its big eyes; the scientists who discovered say that these little guys may represent the limit of miniaturization possible for a vertebrate with complex eyes. Until they find the next smallest-possible one, that is. And on the other end of the spectrum? 10 of the largest living things on the planet