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.
Pygmy rabbits measure between 9.25 and 11.6 inches making them the world’s smallest leporid.
#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.
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 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.
Slender blind snakes can be found in Barbados and grow up to 4.1 inches long.
#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.
Pygmy marmosets are about the size of a human finger.
#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.
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.
Etruscan shrews weigh 0.063 ounces and can only be found in coastal Mediterranean locales and certain areas of Southeast Asia.
#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.
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.
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.
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.
