Top 10 World’s Smallest Animals

Written by Abby Parks
Updated: October 2, 2022
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Key Points

  • Measuring just 0.4 inches, Cuba’s Monte Iberia eleuth is one of the world’s smallest frogs.
  • The 0.7-inch Virgin Islands dwarf gecko is the world’s smallest reptile.
  • The smallest mammal by length is the Kitti’s Hog-Nosed Bat from Burma and Thailand. They’re 1.1-1.3 inches on average.
  • The world’s smallest bird is the 2.2-inch Bee Hummingbird, aka zunzuncito and Helena hummingbird.

What are the smallest animals in the world? Before we begin, let’s define “smallest.” After all, single-celled organisms, which can only be seen with microscopes, are crawling over everything — including our bodies! So, for our smallest animals in the world list, we’re limiting it to animals viewable with unaided human eyes and categorizing them for a more interesting variety.

#10 Smallest Rabbit: Pygmy Rabbit

Pygmy rabbits spend their lives in and around sagebrush. Native to the western United States, the teeny hoppers — which only measure between 9.25 and 11.6 inches — are the world’s smallest leporid. The United States government lists pygmy rabbits as endangered, but the IUCN categorizes them under Least Concern.

Pygmy rabbits are native to the United States, and females of the species are slightly larger than males.

A pygmy rabbit standing in the dirt near grass.
Pygmy rabbits measure between 9.25 and 11.6 inches making them the world’s smallest leporid.

Randy Bjorklund/Shutterstock.com

#9 Smallest Shark: Dwarf Lantern Shark

Measuring in at only 8.3 inches long, dwarf lanterns are the smallest sharks in the world. Experts at camouflage, the pencil-sized swimmers can both glow like a sunray and melt into night shadows. They eat krill, and females give birth to small litters every year. But to see one, a trip to either Venezuela’s or Colombia’s coast is required.

Forty-five species of lantern sharks can be found in deep waters around the world.

A hand holding a dwarf lantern shark in a boat.
Measuring at only 8.3 inches long, dwarf lantern sharks are the smallest sharks in the world.

#8 Smallest Fish: Paedocypris

The smallest fish on the planet is a genus called Paedocypris. Individuals are smaller than a half-inch and live in the waters around Sumatra Island. Due to their size, Paedocyprises are among the few aquatic animals that can persevere through extreme droughts.

The smallest known specimen was 0.3 inches, and the largest was only 0.41 inches.

Paedocypris fish swimming in murky water
Paedocypris are smaller than a half-inch and live in the waters around Sumatra Island.

#7 Smallest Snake: Slender Blind Snakes

Found over a few-square-kilometers in Barbados and believed by scientists to be the world’s smallest snake, slender blinds only grow to about 4.1 inches long. Due to their thinness, the slithering Caribbean dwellers also go by threadsnakes or thread snakes.

The scientific name for the family of small slitherers is Leptotyphlopidae. Species survive on most continents, and they tend to congregate near ant and termite nests.

A slender blind snake slithering on a rock.
Slender blind snakes can be found in Barbados and grow up to 4.1 inches long.

Aks Portfolio/Shutterstock.com

#6 Smallest Monkey: Pygmy Marmosets

Pygmy marmosets live in South American forests and enjoy the distinction of being the world’s smallest monkey. Individuals are about the size of a human finger, 4.6 to 6.2 inches tall, and their big eyes and adorable noses can melt even the coldest heart.

Click here to learn more about pygmy marmosets, which can jump 16 feet.

A pygmy marmoset sitting on a tree branch.
Pygmy marmosets are about the size of a human finger.

Edwin Butter/Shutterstock.com

#5 Smallest Bird: Bee Hummingbird

What is the smallest bird in the world? Honors go to the bee hummingbird — also known as the zunzuncito and Helena hummingbird. The minuscule flyers flap their wings 200 times per minute, and the largest among them is about 2.2 inches and weighs roughly the same as a dime. Bee hummingbirds are endemic to Cuba and haven’t ventured far from the area for over millennia.

Click here to learn more about hummingbirds, which are the only birds that can fly backward.

A blue bee hummingbird perched on a tree branch.
The bee hummingbird is the world’s smallest bird, measuring about 2.2 inches and weighing the same as a dime.

#4 Smallest Mammal by Mass: Etruscan Shrew

Their bodies are only about 1.5 inches long, and their tails add 0.94 to 1.26 inches. The smallest known mammal by mass, Etruscan shrews weigh 0.063 ounces and can only be found in coastal Mediterranean locales and pockets of Southeast Asia. To keep up with their sky-high metabolism, the little critters eat about 25 times a day.

Incredibly, Etruscan shrews have a 1511-beats-per-minute resting heart rate. To put that in perspective, the human heart glugs along between 60 and 100 beats per minute on average.

An Etruscan shrew climbing on a rock.
Etruscan shrews weigh 0.063 ounces and can only be found in coastal Mediterranean locales and certain areas of Southeast Asia.

Wirestock Creators/Shutterstock.com

#3 Smallest Mammal by Length: Kitti’s Hog-Nosed Bat

In the limestone caves of Burma and Thailand live the world’s smallest mammals by length: Kitti’s hog-nosed bats. The average individual is between 1.1 and 1.3 inches. These Near Threatened flying mammals are so compact their heads and bodies form one unit.

Click here to learn more about bats, which give birth upside down.

A Kitti’s hog-nosed bat sitting on a person's finger.
The Kitti’s hog-nosed bat is the smallest mammal by length, measuring between 1.1 and 1.3 inches.

#2 Smallest Reptile: Virgin Island Dwarf Sphaero

Scientists believe the smallest reptile currently scurrying across the planet is the Virgin Island dwarf sphaero. Also known as the Virgin Gorda least gecko and Virgin Islands dwarf gecko, the endangered lizard has only been observed on Virgin Gorda, Tortola, and Moskito Islands. From snout to vent, the Virgin Gorda measures 0.7 inches.

Click here to learn more about lizards, of which there are over 5,000 species!

A Virgin Island dwarf sphaero standing on a red leaf.
The Virgin Island dwarf sphaero is classified as endangered and measures 0.7 inches.

#1 Smallest Frog: Monte Iberia Eleuth

The smallest frog in the Northern Hemisphere is the Monte Iberia eleuth. At only 0.4 inches, they’re about half the size of your thumb! These skittish amphibians spend a lot of time hiding beneath vegetation and are quick to hop away from any perceived threat. They keep to themselves until mating time, and communicate with a characteristically high-pitched sound.

Their striking yellow markings are meant to warn predators of their toxicity–Monte Iberia Eleuths produce pumiliotoxins which paralyze their predators’ muscles so that they can escape harm. Their diet consists of spiders, moths, and other insects like ants.

There are three other mini frog species, and scientists go back and forth about which wears the smallest crown.

Click here to learn more about the Monte Iberia eleuth, which can only be found in Cuba.

A Monte Iberia eleuth perched on a green leaf.
The Monte Iberia eleuth is only found in Cuba and measures about 0.4 inches.

And that’s our list of smallest animals in the world — which can be seen by the naked eye.

Top 10 World’s Smallest Animals Summary

RankAnimalSize
#1Smallest Frog: Monte Iberia Eleuth0.4 inches
#2Smallest Reptile: Virgin Island Dwarf Sphaero0.7 inches
#3Smallest Mammal by Length: Kitti’s Hog-Nosed Bat1.1-1.3 inches
#4Smallest Mammal by Mass: Etruscan Shrew0.063 ounces
#5Smallest Bird: Bee Hummingbird2.2 inches
#6Smallest Monkey: Pygmy Marmosets4.6-6.2 inches
#7Smallest Snake: Slender Blind Snakes4.1 inches
#8Smallest Fish: Paedocypris0.3-0.41 inches
#9Smallest Shark: Dwarf Lantern Shark8.3 inches
#10Smallest Rabbit: Pygmy Rabbit9.25-11.6 inches

Up Next…

If the cute, teeny animals you just met captured your heart, the next ones are sure to amaze you! Discover more outliers in the animal kingdom!

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About the Author

Abby Parks has authored a fiction novel, theatrical plays, short stories, poems, and song lyrics. She's recorded two albums of her original songs, and is a multi-instrumentalist. She has managed a website for folk music and written articles on singer-songwriters, folk bands, and other things folk-music oriented. She's also a radio DJ for a folk music show. As well as having been a pet-parent to rabbits, birds, dogs, and cats, Abby loves seeking sightings of animals in the wild, and has witnessed some more exotic ones such as: Puffins in the Farne Islands, Southern Pudu on the island of Chiloe (Chile), Penguins in the wild, and countless wild animals in the Rocky Mountains (Big Horn Sheep, Mountain Goats, Moose, Elk, Marmots, Beavers).

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