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Weakest Animals: 15 Animals That Are Just Strong Enough to Survive

The weakest animals in the world include zooplankton, ants, earthworms, jellyfish, fairyflies, softshell turtles, sloths, and more.

Nature is all about the survival of the fittest. The strongest, fittest, and toughest animals are able to live on to pass their genes. 

Animals at the top of the food chain are generally considered the strongest. For the strongest to feed, there also has to be weak animals.

There is a multitude of animals that have little to no defense mechanisms to protect themselves and are still thriving in nature. These animals are proof that size is not the only thing that matters. Luck plays a huge role in the survival of any species.

This article discusses the weakest animals in the world and why they make easy meals for their predators.

1. Zooplankton: Too Weak to Swim

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Zooplankton is found deep within the oceans and in freshwater. They are microscopic animals making them difficult to see by the naked eye. These small creatures have no defense mechanism to protect themselves and are completely vulnerable.

Zooplankton is heterotrophic and does not produce their own food. They cannot swim efficiently and usually rely on ocean currents to move from one place to another.

They live in large communities and have several predators, including small fishes, whales, and crustaceans.[1]

Zooplanktons decompose dead fish and absorb carbon dioxide, which helps purify the ecosystem. They also contain a lot of energy, making them the perfect meal for their predators.

2. Ants: Weak Individuals


Ants are some of the smallest animals in the world. They are social animals and live in large colonies. They do so in order to protect themselves.

Like several other insects, ants are decomposers. They eat dead animals, plants, and food.

Ants in groups can kill their predators or large insects. But a single ant is extremely vulnerable and is squashed easily.

Most ants do not have a defense mechanism and are easy targets for their predators. Some ants living in the wild have developed poisonous stings that cause immense pain.

3. Earthworms: Too Weak for Brains


Worms are present in almost every corner of the earth. They decompose dead organisms and serve as the natural cleaners of the world. 

There are many types of worms in nature:

  • Tapeworms
  • Flatworms
  • Roundworms
  • Hookworms
  • Threadworms
  • Earthworms

Earthworms are one of the most common worms found in the world. They do not have eyes, brains, teeth, or bones[2]. Their bodies are soft and squishy, making them one of the most vulnerable animals.

Birds, spiders, beetles, and moles are some of the most common earthworm predators. 

Earthworms do have some defense mechanisms, such as the emitting of a slime called coelomic fluid, which deters predators.[3]

4. Jellyfish: Weakest Body of Marine Animals


Jellyfish are marine animals that have umbrella-shaped bells and tentacles. They exist in nature in a variety of shapes and sizes. 

The bottom side of jellyfish is extremely dangerous as their tentacles sting, which causes excruciating pain. But on top, jellyfish are highly vulnerable. 

Their jelly-tops are not dangerous, and predators easily kill them from above. They do not have a skeleton or any cartilage, making them vulnerable to pressure changes.

5. Tarsiers: Mentally Weak


Tarsiers are small primates native to the islands of Southeast Asia. They have large protruding eyes and eat lizards, insects, and small snakes. Their only defense mechanism is to hide.

Large birds such as eagles and other carnivorous animals prey on tarsiers. Aside from being physically weak, tarsiers are also mentally fragile.

They are known to hurt themselves out of stress and fear. Tarsiers often bash their skull against hard objects, especially when kept in captivity.

Many of them commit suicide, and only a few of them reach maturity.

6. Chickens: Weakest Flight


Chickens are some of the most famous birds in the world, kept by humans as a food source. They are found in almost every country on earth and occur in different breeds.

They use their beak and claws to defend themselves. 

While they do have wings and feathers, chickens can’t fly. As flightless birds, they are easily hunted by their predators, such as coyotes, foxes, raccoons, cats, and wolves.

7. Fairyflies: Smallest Insect

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Fairyflies are one of the smallest insects found in the wild. Their bodies produce light that glows at night. Apart from their small size, fairyflies have a short life of around two to three days.

Their weak bodies make them vulnerable to spiders, wasps, and other insects. They can’t defend themselves, relying on reproduction to survive as a species.

8. Star-Nosed Moles: Weakest Sight

Star-Nosed Moles
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Moles are small mammals that are experts at digging. Star-nosed moles are small semi-aquatic animals found in North America. 

They have terrible eyesight as they live underground in pitch-black darkness where eyesight is useless.

They do have great smelling abilities. Star-nosed moles can detect objects far away using their smell. They also use the feelers on their nose to detect objects. 

9. Softshell Turtles: Weakest Shell of All Turtles

Softshell Turtles

Turtles are known for their tough shells that protect them from predators. This hard outer layer makes it difficult for predators to bite into them. 

But this is not the case with softshell turtles.

Softshell turtles are freshwater turtles native to North America. Unlike most turtles, the spiny softshell turtles have a soft and rubbery shell which makes them vulnerable to predators.

One advantage of having a soft shell is that they are fast. Soft shells are not as heavy as rock-hard turtle shells, increasing their mobility.

10. Anteaters: Weakest Mammal Bite Force

Giant Anteater

Anteaters are carnivorous mammals known for eating ants and termites. One of the most important parts of a carnivore is its bite strength. Animals with a strong bite force are able to fend off attackers. 

Anteaters do not have a bite force and have limited jaw mobility. They have the weakest bite of all mammals, as they don’t have one.

They collect ants and termites by sticking their long tongue out and reaching deep inside colonies. The lack of a bite force makes it vulnerable to attacks from its predators, such as hyenas and wild dogs.

11. Sloths: Too Weak to Run


Sloths are often classified as the slowest animals on the planet. They have a relatively low muscle mass compared to other mammals because they don’t move a lot.

Muscles develop as they are used. But as sloths remain still most of the day, they have adapted to having a low muscle mass.

They have one of the slowest metabolisms among all mammals. They spend most of their lives in trees eating leaves and sleeping. If a predator were to attack, sloths are unable to run and protect themselves.

If a sloth is in a tree, it is likely to remain unharmed though. Sloths are only truly in danger when they venture down to the ground. 

They have some defense mechanisms, such as their long claws that grow up to five inches in length.

12. Barbados Thread Snakes: Weakest Snake

Barbados Thread Snakes
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The Barbados thread snake is the smallest snake in the world. As the name suggests, they are found on the island of Barbados. They are small and reach only a thickness of less than an inch.

These snakes do not have any defense mechanisms and are vulnerable to predators such as eagles and other carnivorous birds. 

Barbados thread snakes are non-venomous and nocturnal.

13. African Pygmy Mice: Weakest Rodent

African Pygmy Mice
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Small rodents are vulnerable to attacks from predators. There are many small rodents in the wild (such as gerbils, mice, rats, and chinchillas), but one is particularly small.

The African pygmy mouse is the smallest mouse species in the world. They grow to a maximum size of three inches and are commonly found in the sub-Saharan region.

Due to their small size, African pygmy mice are vulnerable to harm. They are predated by cats, hyenas, wild dogs, eagles, and carnivorous birds. 

14. Hummingbirds: Weakest Birds


Apodiform birds are one of the smallest and weakest bird groups in the animal kingdom. They eat flowers, plants, and nectar for their diet. 

There are many species included in apodiform birds, from swifts to hummingbirds, but the latter is the smallest. They have small bodies and flap their wings at an amazingly fast rate.

Hummingbirds drink nectar which they get from flowers. Their small bodies make them vulnerable to other large birds and snakes. 

The only defense of hummingbirds is their ability to fly backward, which helps them maneuver in flight more effectively.

15. Pygmy Marmosets: Weakest Primate

Pygmy Marmosets

The pygmy marmoset is the smallest primate species on the planet, native to the rainforests of South America.

They weigh around 3.5 oz (100 grams) and live for about 10 to 12 years. Their bodies are small, with a length of five to six inches. They are often classified under the group of new world monkeys.

Their small size makes them an easy target for eagles, hawks, snakes, and wild cats. The IUCN has classified pygmy marmosets as vulnerable.


Millions of animal species inhabit this earth. Each animal plays an important role in the ecosystem and is part of the food chain. As survival of the fittest rules the animal kingdom, the strongest animals sit at the top of the chain, while the weakest reside at the bottom.

Zooplanktons, hummingbirds, fairyflies, and softshell turtles are some of the weakest animals in the world. Size has a lot to do with weakness and strength, but that is not the only thing that matters. Animals with strong defensive mechanisms against predators are more likely to survive in nature regardless of their size.


What Is the Weakest Animal in the World?

The zooplankton is considered the weakest animal in the world. They are microscopic beings with fragile bodies and no means to protect themselves. They are even too weak to swim.

What Is the Slowest Flying Bird on Earth?

The American woodcock is the slowest-flying bird in the world. They hold a Guinness world record for flying at 5 miles per hour without stopping.

What Were the Weakest Dinosaurs?

There were several dinosaur species which are considered weak for their time based on their size. Microceratus, ohmdenosaurus, tethyshadros, and Compsognathus are some of the weakest dinosaurs that have ever walked on earth. 

About Misfit Animals Staff

The Misfit Animals staff consists of animal lovers, pet enthusiasts, veterinarians, zoologists, and other animal experts. Our goal is to provide people with information on proper animal care.

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