What is the smallest animal in the world?

The size of the animal kingdom might be enormous, but it also contains some truly tiny creatures that would blow your mind with their complexity! Let's take a look at the smallest animals in the world and what makes them tick (pun intended).

Could a frog or an insect be the smallest animal in the world?
Could a frog or an insect be the smallest animal in the world?  © Unsplash / Sergiu Nista, 123RF / Unovidual (TAG24 Edit)

There are 1.3 million animal species out there in that big blue ball we call home, many of which are gigantic.

But size matters both ways, and the tiniest beings are sometimes the most fascinating to look at.

Considering the variety of critters crawling at our fingertips, it's time to take a look at one that is so small that you may well need a magnifying glass to see them!

British shorthair cat in profile: Origins, price, and lifespan
Cat Guide British shorthair cat in profile: Origins, price, and lifespan

You'll notice we didn't say microscope there – that's because we're not going to include microscopic organisms when considering this particular animal record.

With that in mind, here's TAG24's list of the smallest animals in the world!

What's the smallest animal on Earth?

Myxozoa are neither bacteria nor virus, nor single-cell organisms, and are possibly the smallest animals in the world. Indeed, these tiny little aquatic animals are obligate parasites only made up of a couple of cells, yet still breathing oxygen. They have a habit of infecting and living within host animals like fish and birds, and are beyond ancient.

Interestingly, Myxozoa have actually evolved in a backwards direction and once existed as almost jellyfish-like sea animals, before they shrunk into their now microscopic bodies. They have gone through many, many different forms, and are certainly worth looking into - here's a fascinating video to help teach you this mother-of-all trivial pursuit facts.

How small is the smallest animal in the world?

Considering that Myxozoans are typically around ten 75,000ths of an inch, it's probably best to use a more accurate measurement – micrometers. One of these bad-boys is the equivalent of 1/75,000" or one millionth of a meter. Considering this fact, a Myxozoa can vary from ten to one hundred micrometers in size.

In other words, you can't see them (unless you have absolutely wild, inhuman eyesight), and you probably shouldn't try without a microscope. Some of these little parasites are only a few cells in size, despite being capable of many things. These are absolutely tiny and, yet, are still considered animals.

What are the world's other smallest animals?

The world is full of tiny little animals, swimming, flying, and rolling around the place in search of their next feed, and their identities may surprise a few of you. Let's take a look at tiny fish that feed the biggest beasts, a trifling rodent, and a bird that's not much bigger than a bee.

Here are the smallest ocean animals, land animals, and birds in the world.

But wait, what about insects? The smallest insect known to man is the Dicopomorpha Echmepterygis, which measures a meager 0.005 inches in length. That being said, all insects are generally small, so let's move on to some more interesting questions.

Another small ocean animal

Zooplankton are some of the smallest ocean animals living on Earth.
Zooplankton are some of the smallest ocean animals living on Earth.  © IMAGO / Nature Picture Library

If you have ever seen Finding Nemo, a little bit of plankton-based nostalgia might be tickling your fancy right now. These tiny aquatic organisms drift upon the currents of the sea, eating tiny plants and animals as they go.

Zooplankton are one of the tiniest ocean animals on Earth, not including the likes of the Myxozoa.

They range from microscopic to tiny little jellyfish-like creatures, and should be distinguished from the more widely known Phytoplankton. Those are a self-feeding plant, while the former are an animal that needs to feed on others in order to survive.

Smallest land animal in the world

The Etruscan Shrew is the smallest mammal and land animal in the world.
The Etruscan Shrew is the smallest mammal and land animal in the world.  © IMAGO / Nature Picture Library

Fitting between the knuckles of your index finger, the Etruscan shrew is the smallest mammal known to man, coming in at only 1-1.5 inches in length. They generally weigh only a little more than half an ounce, a weight that is very much dependent on their day's feed.

These tiny little rodents are reminiscent of a mouse or rat, but far cuter. They eat about 1–2 times their body weight's worth of food every single day, not sharing their food with any family members due to a loneliness observed by the entire species. Etruscan shrews are lone wolves throughout their lives, only coming together during mating periods.

Smallest birds in the world

The Bee Hummingbird is the smallest bird, and somewhat like an insect.
The Bee Hummingbird is the smallest bird, and somewhat like an insect.  © IMAGO / Wirestock

The Bee Hummingbird straddles the line between insect and bird, being only a little larger than the humble bumblebee. This tiny little bird is a native of Cuba, measuring in at only about 2–3 inches in length. They weigh about 1 ounce, making the Bee Hummingbird the smallest and lightest bird in the world.

These little feathered fellows are small, colorful, and incredibly beautiful – if you can get close enough to actually see them properly.

As well as residing on the main island of Cuba, the Bbee hummingbird can also be found on the Isla de la Juventud and in the West Indies. They are gorgeous, and unbelievably small!

The smallest animal in the world: A matter of definition

Now, in a way, all of these answers could be considered wrong. Of course, no one can compete with microscopic organisms like bacteria and viruses when it comes to this particular record.

It's a matter of definition. Are bacteria "animals", or do they need to become a little more complex before that?

Still, these complex and often magically beautiful creatures have a claim of their own to being the smallest animals in the world!

Cover photo: Unsplash / Sergiu Nista, 123RF / Unovidual (TAG24 Edit)

More on Animal World Records: