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.
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.
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.
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.
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.
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.
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 over millennia.
Click here to learn more about hummingbirds, which are the only birds that can fly backward.
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.
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.
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!
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! 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.
And that’s our list of smallest animals in the world — which can be seen by the unassisted human eye. Next up: the planet’s friendliest animals!