What are some interesting facts about biology?

Biology has tons of mind-blowing discovers, from indestructible tardigrades, immortal jellyfish, and self-destructing sea cucumbers.

What are the 5 main branches of natural science?

The five main branches are biology, chemistry, physics, earth science, and astronomy. It covers everything from the smallest atom to the infinite universe.

What is the definition of biology?

Biology is the study of living organisms, such as how they grow evolve, function, and interact with each other and their environment.

What are the main branches of biology?

The main branches of biology are botany (plants), zoology (animals), microbiology (microorganisms), genetics, ecology, and evolutionary biology.

Why is biology important to everyday life?

Biology helps us understand our bodies, develop new medicines, create sustainable food supplies, protect the environment and animals, and more.

What are some weird facts about biology?

Some weird facts about biology are that humans shed about 40 pounds of skin in a lifetime, fingerprints actually change over time, we grow a new stomach lining every few days, and sea cucumbers expel their own innards as a defense mechanism.

What is the smallest living thing on Earth?

The smallest known organism on earth is Mycoplamsma genitalium. It is a single-celled bacterium that is just 200 nanometers wide, which is small enough for hundreds of thousands to fit inside a single grain of sand.

How does DAN control life?

DNA contains the genetic instructions for each cell. It is a biological blueprint of almost every living things ("almost" because some viruses don't have DNA; they have RNA). Some scientists don't consider viruses alive, so there is some debate!

What are some of the most fascinating animal adaptations?

Frogs can freeze and then come back to life; chameleons change color to regulate temperate, and sea cucumbers can expel their insides. Biology truly has some crazy survival tricks.

Where can I find more fun biology facts?

Check out FactRetriever's Science Facts page for more crazy discoveries about the natural world, human beings, and life!

Which biology fact blew your mind?

Share your favorite fact on social media with #FactRetriever and tag us, and we might feature your favorite in our next article!

35 Biology Facts that Sound Made-Up (But are Totally Real)

By Karin Lehnardt, Senior Writer

Published May 1, 2025Updated November 9, 2025

Did you know that a sloth can take two weeks to digest a meal or that sea cucumbers explode? From strange animal behavior to bizarre human human body facts, these crazy biology tidbits are full of mind-bending surprises. These facts will not only amaze you; they will make you want to text someone right now. Read on, and share your favorites!

Incredible Animal Facts

Sloths Digest Breakfast for Two Weeks
A sloth can take two weeks to digest a single meal. Imagine chewing your breakfast for 14 days!_[13]
Lobsters Have Rainbow Blood
A lobster's blood is colorless. However, when it is exposed to oxygen, it turns to blue._[14]

Meet the jellyfish that cheats death. This amazing creature can reverse its aging process, over and over again

Immortal Jellyfish?
The Turritopsis dohrnii jellyfish can revert its cells to a younger state, potentially even biologically living forever._[13]
Sea Cucumbers Explode to Escape
To escape predators, some sea cucumbers can eject their internal organs. Later, they can regrow them._[13]
Some Animals Can Detect Magnetic Fields
Magneto-reception allows animals to detect magnetic fields; to determine location, altitude, and direction. These animals include bacteria, nematodes, birds, and some mammals._[13]
Caterpillars Have 12 Eyes
Most caterpillars have 12 simple eyes. Called ocelli, they line the caterpillars' heads._[13]
Tardigrades Survive Everything

Tardigrades, or water bears, are practically indestructible and can survive everything, including radiation, boiling, freezing, and even space.
_[13]

Meet the tardigrade of "water bear" a nearly indestructible micro-animal that can survive in space

Some Snakes Can Sense Body Heat in the Dark
Pit vipers, for example, can see infrared images, similar to a thermal camera_[7]
Frogs Can Completely Freeze
In the winter, wood frogs can completely freeze, and, in the spring, they come back to life._[13]
Surprising Human Body Facts

Humans Glow in the Dark
Humans give off a small amount of light that is too weak for the naked eye. But we still kinda glow._[13]
The Tongue is the Fastest Healing Part of the Body
The tongue heals quickly thanks to its rich blood supply, the presences of proteins in saliva, a simpler cell structure, and a healthy amount of oral bacteria that reduces inflammation. _[2]
Humans Can't Regrow Limbs . . . Here's Why
We have the blueprints for regrowth; we just can't access them. We lose the ability because 1) humans have macrophages, which build scar tissue instead of limbs, 2) a gene called LIN 28a, which regenerates tissues is inactive in mammals after infancy, and 3) humans have more complex bodies, so regrowing limbs is more difficult._[13]
Your Stomach Lining Rebuilds Itself Every 3 Days
Your stomach lining rebuilds itself every three days to avoid digesting itself!_[13]
The Only Organs that Can Float on Water
The lungs are the only organs that can float on water. Their air-filled structure makes them buoyant, like tiny "floaties."_[9]
Your Bones Are Alive
Bones are not solid, static structures. They constantly regenerate and replace themselves every 10 years._[13]
When Corpses Turn into Soap
Sometimes human corpses can become saponified, which is when the body undergoes a chemical reaction that turns body fat into adipocere. Adipocere feels like semi-hard cheese and has a soapy texture. The most famous instance of this happening is the "Soap Lady," 140-year-old "mummy on display in Pennsylvania._[11]
Humans have Far More than Five Senses
Some of the most important senses include vision, hearing, smell, taste, touch, balance, temperature, proprioception, and pain._[13]
The Most Abundant Molecule in the Cell is Water
Water accounts for 70% of a cell's total mass._[13]
Laughing While Being Tickled Can be a Fear or Panic Response
Laughing when tickled is your brain's way of telling you that there is something crawling on you. The laugh can be an expression of fear or panic._[16]
Fascinating Plant & Biodiversity Facts

Mangos Belong to the Same Family as Poison Ivy
Both plants produce an irritating substance called urushiol._[12]

Biodiversity is foundational to biology

Biology is the Study of all Life and Living Things

Biology is one of the divisions of the natural sciences, including physics, chemistry, Earth sciences, and astronomy.
_[13]
Bananas are Berries. Kiwis are Not
Botanically speaking, bananas qualify as berries, but kiwis don't._[13]
Trees Can "Talk" Underground
Through a network or roots and fungi, trees can share nutrients and even communicate with each other._[5]
Some Plants Can Hear
Certain plants respond to the sound of insects chewing on parts of the plant, which triggers a chemical defense._[10]
There are Mushrooms that Turns Ants into Zombie
Ophiocordyceps take over an ant's brain and forces it to climb. It then erupts out of the ant's skull._[15]
Earth has Millions of Different Kinds of Life . . . and Counting
While many are still undiscovered, rich biodiversity is crucial for the health of our planet. Scientists estimate that there are over 8 million species on Earth. _[13]
Incredible Scientific Discoveries

The Man Who Discovered Germs . . . 300 Years Too Early
In the 1500s, Italian scientist Girolamo Fracastoro, proposed a scientific germ theory of disease more than 300 years before Louis Pasteur and Robert Koch proved germs were real. His idea was so ahead of its time, that most people didn't believe him._[4][13]

Aristotle is considered the Father of Biology. He was one of the first people to study the natural world with systematic observations rather than connecting natural occurrences to divine interference

Aristotle: The Father of Biology
The 4th century Greek philosopher Aristotle is known as the Father of Biology. He was the first person to systematically describe and classify the living the world, which laid the foundation for the modern branch of biological studies._[13]
The Man Who First Saw Bacteria
Dutch microscopist Antonie van Leeuwenhoek (1632-1723) was the first person to observe bacteria and protozoa. His research disproved spontaneous generation and laid the foundations for bacteriology and protozoology. He is considered the "Father of Microbiology."_[1]
The Man Who Saw the First Cell
Robert Hooke discovered the first cell in 1665 while examining a cork under a microscope, a discovery that revolutionized biology forever. Hooke: "All of life's building blocks . . . spotted in a piece of dead cork!"_[6]
John Ray Defined Species

English naturalist and botanist, John Ray (1627-1705) established the modern idea of species as the ultimate way to organize the world. He contributed significantly to taxonomy and biological classification.
_[8]
Famous Biologists

Famous biologists include Charles Darwin, Carl Linnaeus, Alexander Fleming, Robert Hooke, Jane Goodall, Louis Pasteur, Aristotle, and more.
_[13]

Biologists who have changed the world

The Anatomical Theater of Padua in Northern Italy is the first permanent anatomical theater in the world

The Father of Embryology . . . Who Also Built a Dissection Theater

Italian physician Girolamo Fabrizio is called the "Father of Embryology" and built a theater for public anatomical dissections.
_[4]
The First Human Blood Transfusion . . . From a Sheep

In 1667, French physician Jean-Baptiste Denys performed the first fully documented human blood transfusion and a xenotransfusion between a boy and a sheep. Early scientists believed the qualities of animal, the purity of lamb, for example, could be transmitted to humans through blood.
_[13]
The Man with Two Faces . . . Who Never Existed

In the medical case study book Anomalies and Curiosities of Medicine, there is the case of Edward Mordake, a man with supposedly two faces. Although it has made the rounds on social media as "weird biology," it is completely fabricated.
_[3]