When our distant ancestors left the trees to walk the savannas, physical changes occurred that can still be seen today. Some are vestigial and no longer needed, while others endure as efficiently as always.

In fact, modern humans can thank several ancient perks for their survival, including laughter and eyebrows. Human evolution is far from over. From changing female voices to genes that ruin drinking games, things are set to get more interesting.

10 Nails Are Really Ancient

Primates sprouted nails as far back as 58 million years ago. This provided the tree-dwelling creatures with several benefits. The main job was to better equip them to navigate trees, to which they were basically confined.

Nails strengthened the fingers, allowing for a better grip, and protected the nerve endings that permitted the fingertips to feel the world. They also brought food perks. Compared to other tree animals, primates excel at harvesting fruit at the end of branches—a tricky feat that requires good maneuvering and a great grip on the narrowing foliage.^[1]

Humans no longer nest in trees. At one point, an ancestor decided that the land was a better deal. As the lineage evolved, people ended up in caves and eventually penthouses.

Through all the physical changes, including a radical habitat shift and thousands of years, humans retained their claws. The “tree dexterity” of nails simply switched over into productive toolmaking and the infinite tasks that human hands can do today.

9 The Purpose Of Laughter

At first, laughter seems straightforward. Humans laugh when they find something funny (or pretend to). Looking back, it would appear that lives depended on how social and amiable one seemed. Nobody would have invited the caveman with the killer stare and argumentative nature. Nope. In winter, they probably left him outside the cave and watched him expire.

Studies have shown that laughter is a powerful social glue. Back in the day, the habit probably evolved as a verbal way to cement alliances and negate violence. While aggression was always a primary human trait, one might be less inclined to strangle the guy who laughed at your jokes during the last meeting at Stonehenge.

Interestingly, while fake laughter appears to lower the same barriers as a genuine cackle, it might not fool outsiders. During a 2016 study, volunteers from 24 different societies accurately detected pairs of strangers or two friends just by listening to one of them laugh.^[2]

8 Unexpected Female Dating Voice

In 2018, researchers herded 30 speed daters together. The women stayed at the tables, while the guys rotated every six minutes. Each had to mark a card showing whether they fancied the other person or not.

When researchers listened to the recorded conversations afterward, it became clear that both genders lowered their tones with somebody they liked. This clashed with previous studies showing that men were attracted to women with higher voices because they sounded younger and more feminine.

The surprising mutual drop in tone has not been solved, although researchers agree that it could be an evolutionary tool to snag a mate. Some suggest that the women used a more dominant pitch in the competitive environment of speed dating.

However, others feel that a quieter way of talking is a lot more intimate. When dating happens in a room full of people, a woman might drop her voice merely for privacy.

Interestingly, voice recordings of women in 1945 compared to ones taken during the 1990s showed that the female tone has lowered. This could be because women are trying to communicate maturity, competence, and dominance in a more equal opportunity world.^[3]

7 The Human Fur Mystery

Compared to other animals, humans are fairly bald. Fur kept our earliest ancestors warm, protected their skin, and provided camouflage. Something pressured evolution to erase it.

The prevailing theory suggests that it was the ancestral decision to abandon trees for living in the open savannas. This new environment would have been a lot hotter. A body covered in hair would have made living and hunting in the sun’s heat impossible.^[4]

It is also thought that human sweat glands boomed when hair turned sparse. In fact, modern humans are the sweatiest primates on the planet. Around five million glands produce up to 12 liters (3 gal) of sweat daily. This amount would have kept humans cool in the savannas but only if they were hairless.

The neat-sounding theory has many holes. It cannot be proven that hair loss and the sweat gland explosion occurred at the same time. Researchers are also uncertain how these individuals dealt with excessively cold temperatures, what genes were involved, or even when human fur vanished.

6 Slow Big Toe

In 2018, a study identified the big toe as one of the last foot bones to evolve after humans crossed over from tree-swinging to ground-dwelling ancestors. To walk upright took a major overhaul of the feet. The big toe was instrumental in this change because it allows traction during walking.

Despite its importance, the largest toe stuck to its primate origins the longest. This was probably because it was the most difficult to change. In the beginning, the toe was almost like a finger, grasping branches and working as a tool.

This highly useful feature had to turn rigid to ensure effective locomotion on two legs. For this reason, the change occurred gradually over millions of years.^[5]

The study’s findings were surprising in a way. The big toe remained opposable for much longer than thought, proving that it did not truly interfere with the ability to walk efficiently.

5 Why Men Have Nipples

Male mammals cannot feed their young, and yet they have the tools to nurse. Some men even lactate, although this is usually due to a hormonal problem. Guy nipples are not an evolutionary quirk. They are the result of a biological process that prevented evolution from erasing a useless trait.

A mammal embryo has the potential to become either sex. When the time comes to swing one way or the other, the embryo’s chromosome set decides the gender. If the male XY set is present, a gene called SRY activates and ushers in everything the embryo needs to develop into a boy.

However, there is another process that happens before the male genetic switch can flip. In mammals, the mammary glands begin to develop extremely early and these glands do not care for any old chromosome set. They set the stage for breast tissue and nipples, and there is nothing that SRY or evolution can do about it.^[6]

4 A Useless Tendon

There are times when evolution cannot be bothered to sweep up the leftovers. One of the most useless things that nature left in the human body is the palmaris longus tendon. It is quite a prominent feature in the wrist. Most people can see it when they touch their thumb and pinkie together and slightly tilt the hand toward themselves.

A raised line will appear in the middle of the wrist. If not, they are among the 10–15 percent of people who were born without it. The tendon connects to the palmaris longus muscle but does not make it stronger. The only time it serves a purpose is when surgeons remove and use it elsewhere in the body during plastic and reconstructive surgery.^[7]

It remains unclear why humans have this useless tendon. A tentative guess considers it a relic from a time when the forearms were used as much as the legs to move around. Why? Modern mammals with the most developed palmaris longus tendon do just that—including monkeys and lemurs.

3 Eyebrows Saved The Species

Eyebrows serve one obvious purpose today. They act as a protective barrier for the eyes by stopping rolling fluids and debris. But in 2018, researchers made a surprising case: Without eyebrows, humans might have gone extinct like the Neanderthals.

Sounds extreme, but the proof could be in the brow bone. Neanderthals and other ancient hominids had prominent bony ridges above the eyes, very much like some primates today. Studies showed that this ridge, which is absent in humans, had no real purpose other than to look fierce.

Looking fierce in a primitive world is not always the wisest move. Tempers flare, and clubs start swinging. Worse, this ridge prevented Neanderthals from maneuvering their eyebrows to look friendlier. That was the difference that might have saved the human race. Our eyebrows convey subtle signals of compassion, sympathy, and friendliness.^[8]

The fossil record backs up this wacky-sounding hypothesis. The human brow ridge started to recede during a time when important social connections began between distant groups. Being able to eyebrow-signal one’s friendliness would have gained more allies than enemies—and thus more power.

2 The Returning Bone

There is something strange going on with the human kneecap. It was once accompanied by a tiny bone called the fabella. It did the same job as a modern kneecap for Old World monkeys about a zillion years ago. As humans evolved, it shrunk and eventually got lost. However, it just took a few knee operations and scans to notice that the fabella was still present in some people.

In 2019, researchers threw out a wide net. They reviewed medical records from 27 countries that involved more than 21,000 knees. The results were clear. The tiny bone was coming back.

The records spanned almost a century, and the earliest showed that around 17.9 percent of the population had it in 1875. Only 11.2 percent had it in 1918. However, by 2018, around 39 percent of people were estimated to possess the returning relic.

Evolution is not always positive. Those with a fabella are more likely to suffer inflammation, osteoarthritis, and a variety of knee problems. The boomerang act remains unsolved, but it could have something to do with bigger, better-nourished modern humans putting more pressure on the knee.^[9]

1 The Hangover Genes

One of the weirdest ways humans are still evolving concerns the alcohol dehydrogenase (ADH) gene cluster. In 2018, researchers found signs that the region was changing—which is not good news for those who like their liquor.

Normally, when a person guzzles a beer or 50, the body breaks down the alcohol into toxic acetaldehyde. When this stuff accumulates, the drinker no longer feels so jolly. The face flushes, and the person experiences nausea and a rapid heartbeat. Typically, acetaldehyde is quickly metabolized into a less bothersome acetate that is easily eliminated from the body.

Some individuals with East Asian and West African ancestry showed an evolved ADH cluster, which makes drinking uncomfortable really quickly. This adaptation makes it difficult to process alcohol, so such people are struck down faster with super hangovers. It is not clear how quickly the adaptation is spreading to other populations or whether the genes changed in an attempt to shield humans from drunkenness.^[10]

Without getting too deep in the weeds in explaining the Theory of Evolution, it is an established scientific theory that explains the evolution of species. It’s one of those things people who understand it fully support, those who kind of get it don’t consider, and the people who see it as a rejection of their faith obsessively oppose.

Over the years since Darwin and Wallace established an understanding of Natural Selection, which is the basis for the theory, many strange and bizarre claims have emerged trying to dispute it. Some are well known while others are only found in the deepest, darkest recesses of the Internet. Here are the ten most bizarre claims made by people trying to prove Evolution is “Just a theory.”

See Also: 10 Ways Evolution Made Humans Worse

10 Evolution Is Just A Theory

As any scientist will tell you, a theory in science is not the same thing as that idea you get when you’re trying to figure out who stole your pudding out of the shared office fridge. In science, a theory is a collection of observable and testable facts compiled over a usually extended period of time by a wide number of people. Consider the Theory of Gravity or the Theory of Planetary Motion. These aren’t guesses people like Copernicus, Newton, and Kepler made while sitting in the tub one evening… They collected data over years of study and compiled them into a theory that has since been tested, proven, disproven, added to, and changed.

The beauty of a scientific theory is that it is not set in stone. Nothing is absolute, as any new observation can change it. The current Theory of Evolution contains observations made that were impossible in Darwin and Wallace’s day. With new technologies and advancements allowing for the study of individual cells, DNA, and other aspects of life, the theory has changed significantly since it was first forwarded in the 19th century. The claim that “Evolution is just a theory” serves only to prove the person saying it doesn’t understand what a theory is—it doesn’t prove Evolution isn’t true.^[1]

9 The Fossil Record Is Incomplete

Of course, the fossil record is incomplete. When an organism is fossilized, it has essentially won the prize few animals or plants ever achieve. Fossilization is a truly rare event, which only occurs when the perfect situation allows for it. An organism has to be in the right place at the right time for their body to be fossilized, and that doesn’t guarantee the fossil will survive for millions of years to be found by humans. Because of this, the tiniest fraction of living organisms are ever fossilized and found. Granted, we have found millions of fossils, but if you consider the number of living organisms that have existed on the planet since life first arose, the number is infinitesimally small.

Because fossils are so rare, we are constantly finding new organisms that fit into the record to help explain the changes seen over time that lead to new species arising. Whenever this occurs, it provides new answers, but also creates new questions. Those who don’t believe in evolution point to these so-called “gaps” as the reason Evolution is false. The animated series Futurama once did a great bit on how each time a new species was found to fill a gap, a new gap was created. There will always be “missing links” in the fossil record, but none that disproves the theory.^[2]

8 It Relies Too Heavily On Chance Making It Mathematically Impossible

Back in 1973, an article was published in an issue of Acts & Facts, which outlined the Creationist stance of “The Mathematical Impossibility of Evolution.” The article fails in a number of respects, but like most arguments against evolution in favor of the Biblical story of Creation, it shows that the author, Henry M. Morris, Ph.D. didn’t fully understand the theory he was attempting to disprove. Despite this, people have raised the mathematical impossibility of evolution ever since.

The postulation argues that because mutations occur randomly, and only the so-called “good” mutations are retained, the time needed for single-cell organisms to evolve into mankind is impossible. Dr. Morris threw some numbers out, which suggests that an organism with 200 successive mutations would require a chance of on in 1060 ((10 to the 60th power)). It seems his position relies on the total misunderstanding of how natural selection works, but this hasn’t stopped people from raising this issue whenever they argue against the Theory of Evolution.^[3]

7 Evolution Has Never Been Observed

The argument that evolution has never been observed, is not testable, and isn’t falsifiable is patently false. Regardless, this claim comes up a lot on the Internet, and it generally stems from the incorrect assumption that an animal of one species has offspring of a completely different species. This isn’t how evolution… or any aspect of biology works. These claims are often brought up with another misconception related to microevolution and macroevolution. The former looks at changes within species over time, while the latter involves changes that may result in speciation.

Macroevolution can be observed in the fossil record, and through DNA analysis, though it does take a considerable amount of time, but microevolution can be observed. Because microevolution revolves around the study of changes in gene frequency within a population, it can be observed in much shorter periods of time. Insects work well in this area due to their short life cycle. One example that’s easy to explain shows how populations of insects pass on a gene responsible for pesticide resistance to subsequent generations. This reduces the efficacy of pesticides and shows how the DNA changes from one generation to the next, ultimately rendering that pesticide ‘mostly harmless’ to the population.^[4]

6It Defies The Second Law Of Thermodynamics

The Second Law of Thermodynamics states that “the state of entropy of the entire universe, as an isolated system, will always increase over time. The 2nd Law also states that the changes in the entropy in the universe can never be negative.” When the 2nd Law is brought up by people attempting to disprove evolution, all they manage to do is prove they don’t understand the 2nd Law. The argument suggests that living cells could never have evolved from inanimate chemicals, and similarly, multicellular life couldn’t have evolved from protozoa due to an increase in complexity.

The misunderstanding would also apply to something like a snowflake, which is a complex structure that forms from disorderly parts, but as we all know, snowflakes exist. Essentially, the misunderstanding of a closed system is the reason this argument is often cited. The planet Earth is not a closed system, as energy from the sun can increase complexity. Similarly, multicellular life can increase in complexity by consuming—absorbing lower forms of life, which effectively balances out the purported decrease in entropy across the universe.^[5]

5Not All Scientists Support It So It Must Be False

This argument always comes about when someone attempts to poke holes in the Theory of Evolution by saying it isn’t supported 100% by scientists. That may be true, but if only four out of five dentists can get behind a product, which amounts to 80% support, does that mean the product is absolutely worthless? Conversely, in terms of biologists who understand and accept the Theory of Evolution, it’s more like 98%. Frankly, it’s not possible to work in biology without a proper understanding of Evolution, but that’s not necessarily true of scientists who work in other fields, which may account for the 2%.

The numbers of people who don’t work in a scientific field are far different. Roughly three-quarters of Americans believe that there is a scientific consensus regarding the evolution of life. When people who don’t support the Theory of Evolution were polled in a Pew Research Study, 46% believed there was a scientific consensus, while 52% believed that most biological scientists believe humans (and other forms of life) have always existed in their present form. The difference is staggering, but it’s easy to see why this argument is often raised in an attempt to disprove evolution. Of course, to be intellectually honest we do need to say that while a lack of consensus doesn’t disprove a theory, a total consensus doesn’t prove a theory either. Science is not a popularity contest.^[6]

4 Evolution Cannot Explain How Life First Appeared On Earth

Evolution is the study of how life changes over time, it has absolutely nothing to do with the origin of life, but most people who don’t understand what evolutionary theory is, bring this argument up often. Evolution certainly has a lot to do with what happened to life after it first appeared, but it doesn’t deal with how life got there in the first place. The area of study that revolves around the origin of life is called abiogenesis, and it deals with the prevailing scientific hypothesis that a single event caused non-living materials to transition into living ones, though that event has yet to be identified.

That’s when evolution would step into the equation, not before, and it doesn’t attempt to explain how life started. Even if the scientific community accepts the theory that life began through some extraterrestrial or supernatural means, the evolution of organisms over the following 3.5+ billion years is observable and quantifiable. That being said, biochemists have discovered a means by which primitive nucleic acids and amino acids may have formed and organized into self-replicating units, which could have been the event by which inanimate ingredients formed into the foundational elements of cellular biochemistry, but that’s not the Theory of Evolution.^[7]

3 If Humans Evolved From Monkeys Then Why Are There Still Monkeys?

For some reason, this question is one that is often repeated by people attempting to disprove evolution, but the answer is simple. Humans didn’t evolve from monkeys. That should settle the argument, but sadly, it rarely works in quieting the question. Humans are hominids, which is a family of animals known as the great apes. These include humans, chimpanzees, orangutan, gorillas, and bonobo. Humans remain the only surviving species of the genus homo, which once included Neanderthals, Homo erectus, and many more.

Monkeys, on the other hand, are simians who do share a common ancestor with humans and other members of the primate order. Humans are most closely related to chimpanzees, who share a common ancestor dating back some six to seven million years. Monkeys and humans’ common ancestry extends much further in the fossil record. The common ancestor between monkeys and humans lived about 25 million years ago. This argument has no basis in fact and instead relies on a misunderstanding of how speciation works in transitioning one species to another.^[8]

2 The Banana Argument

Ray Comfort is a New Zealand creationist and televangelist, who once used a banana as an example of the so-called theory of Intelligent Design. Comfort attempted to explain that “the banana and the hand are perfectly made, one for the other.” He believed that the human hand was designed to hold a banana, which was shaped perfectly for our enjoyment. He further declared the peel was nature’s way of keeping bananas safe and edible for people, it has a tab at the top for easy opening, and it, therefore, disproved evolution and proved God’s existence. Here’s the problem with his claim; modern bananas are the product of years of human-imposed genetic manipulation through cross-pollination, and if it proves anything, it’s that species can change over time, as bananas are an example of human-manipulation of evolutionary mechanisms.

Wild bananas are small, filled with seeds, and they taste terrible. Eventually, Comfort admitted his mistake/misunderstanding of how modern bananas came to be, saying he “was not aware that the common banana had been so modified through hybridization.” Intelligent Design was created as an attempt at bringing Creationism into the classroom by claiming it was another theory that could explain the origin of life. It didn’t take long for lawsuits and common sense to win in the end, but Creationists still try to push Intelligent Design as a viable theory, which should be taught in biology classrooms.^[9]

1 The Crocoduck

Unfortunately, Ray Comfort’s use of the banana to explain his beliefs against evolution didn’t stop with the fruit. Comfort paired up with Kirk Cameron of Growing Pains fame to refute the existence of transitional fossils, which are organisms found in the fossil record showing traits of a parent and descendant species. They are useful in showing how one species transitioned over a long period of time into another, but Cameron and Comfort completely misunderstood what transitional fossils were when they pulled out a picture of what they called a “crocoduck,” claiming that evolution was false because nobody had ever found one. Cameron appeared as an expert on Fox News, where he made his claim, and the Internet had a field day.

Amusingly, Cameron and Comfort’s creation came back to bite them in the rear when an organism was discovered, showing traits of both ducks and crocodiles. In 2003, a new species of ancient crocodile was found and later identified, which had a large, flat snout reminiscent of a duck’s bill. The new species was named Anatosuchus, which translates into “duck crocodile,” or, in Cameron’s words, “A crocoduck!” Technically, it’s not a duck’s bill, as it includes rows of teeth and is entirely crocodilian, but you can’t say paleontologists didn’t have a chuckle when the crocoduck entered the lexicon.^[10]

We think of human evolution as a natural, step-by-step feature of life on Earth, even if all evidence suggests that it’s not the case. Over the eons, life on Earth had to go through many different, unique steps to lead to the evolution of modern humans, including our decision to stand up on two feet instead of four and move from hunter-gatherer societies to settled, farming communities. 

10. Last Universal Common Ancestor

LUCA refers to the Last Universal Common Ancestor – a theoretical ancestor to all life forms that exist today. Existing some time around four billion years ago, it would have played a pivotal role in the evolution of life on Earth. 

According to simulations, it would have lived deep underground in iron-sulfur rich hydrothermal vents, possibly in dark, metal-rich environments. It would have also been anaerobic and autotrophic, not relying on oxygen and producing its own food from hydrogen, carbon dioxide, and nitrogen. 

According to many scientists working on tracing the genetic tree of life, LUCA would be the root of the tree and the beginning of life’s evolutionary journey. Sadly, LUCA’s exact physical organization and properties remain theoretical and – to a large extent – imaginary. While the traditional understanding of evolutionary sciences depict LUCA as the last common ancestor of archaea, bacteria, and eukaryotes – the three main branches of life forms that exist today – our understanding of the subject has also undergone significant changes due to new data and analytical techniques in the past few years, further muddying our understanding of the evolution of early life. 

9. The Great Oxidation

The Great Oxygenation Event happened some time around 2.7 billion years ago, when the planet’s atmosphere had no free oxygen and life primarily consisted of anaerobic organisms that didn’t rely on it to survive. The emergence of a group of microbes called cyanobacteria, however, profoundly changed that equation, as this was when they developed the ability to carry out photosynthesis and produce oxygen as a waste product. As they thrived and released huge amounts of oxygen into the oceans, it gradually accumulated in the atmosphere and laid the basis for most modern life today.

This sudden rise of free oxygen had far-reaching consequences for life on Earth. While it became vital for the evolution of aerobic organisms, the oxygen proved to be toxic for the anaerobic cyanobacteria and many other anaerobic life forms, leading to a mass extinction that wiped out over 90% of life on Earth. A few life forms managed to adapt and utilize the newly-available free oxygen, leading to the evolution of aerobic metabolism. The Great Oxygenation Event was a turning point in Earth’s history that completely altered the planet’s chemistry, paving the way for diverse, oxygen-based organisms we see everywhere around us today. 

8. Evolution Of Complex Cells – Eukaryotes

The evolution of complex cells, or eukaryotes, was a major milestone in the history of life on Earth. Prokaryotes, or simple cells like bacteria, emerged around four billion years ago as some of the most ancient life forms. Eukaryotes, however, do not appear in the fossil record until over a billion years later, around 2.7 billion years ago. The origin of eukaryotic cells still remains a mystery, though we know that it was a turning point for the evolution of all complex life found around the world today. 

The primary difference between eukaryotic and prokaryotic cells lies in their complexity. Cells found in eukaryotic organisms contain a nucleus, specialized organs for energy production like mitochondria, and a cytoskeleton that provides structural support and allows for the movement and growth of complex cells. While their origin still remains a scientific mystery, they directly gave rise to all modern multicellular organisms, including humans.

7. Multicellularity

The emergence of multicellularity was another important step during our evolution, as multicellular organisms display many properties that arise from communication between cells and their environment. Many recent studies have proved the importance of these dynamic interactions in various biological processes found across the tree of life today, including collective cell migration, cell differentiation, and cell proliferation. 

Throughout our history, multicellularity has emerged out of single-celled organisms at different times, even if we don’t quite understand how it happened. The capacity to form multiple cells and specialized cell types, in turn, has resulted in the evolution of diverse organisms, including plants, animals, algae, and fungi. Multicellularity has also had a huge impact on Earth’s biodiversity and ecological complexity, as without it, our planet would lack the diversity of life forms we observe today.

6. Cambrian Explosion

The Cambrian Explosion refers to the emergence of a surprisingly-high number of organisms around the planet about 541 to 530 million years ago. Many major classes of animals that make up modern animal life showed up during this period, leading to the diversification of life forms. The evolution of hard body parts like calcium carbonate shells allowed for better-preserved fossil specimens to study and analyze, leading to a better understanding of this time than any other period in the early history of life on Earth. 

While there are still some doubts about exactly what caused the Cambrian explosion, we know that increased oxygen levels in the atmosphere around this time likely played a role in this unprecedented proliferation of complex animals across diverse types of ecosystems on Earth. The rapid appearance of various marine animals during this time profoundly impacted Earth’s biodiversity, setting the stage for further expansions in the coming periods. 

5. The First Sea Animals Move To Land

The first marine animals started moving to land more than 470 million years ago, when plants colonized the mainland during the Ordovician period. Their presence fundamentally altered land ecosystems, as it oxygenated the atmosphere, shaped the soil for future plant evolution, and established new climatic conditions that could house the oncoming diversity of animals. 

While organisms like arthropods, myriapods, and arachnids came to land during the Silurian period around 430 million years ago, insects – or hexapods – followed around the beginning of the Devonian period around 410 million years ago. This transition from marine to terrestrial life was a major turning point in the early history of the planet, leading to the evolution of life on Earth as we know it today. 

4. Bipedalism

The ability to walk entirely on two feet – or bipedalism – represents a distinct evolutionary milestone in human evolution, setting us apart from other four-legged apes. This adaptation is marked in our evolutionary history by several changes in the spine, pelvis, skull, and feet, enabling hominids to stand upright and walk on two legs. However, all this came at a high cost, like overloaded lower backs and lower extremity joints that now cause knee and back pain later in life, especially for females during childbirth. 

Initially, scientists believed that it was big brains that distinguish hominids from other species. The discovery of the Taung Child’s skull by Raymond Dart in the 1920s, however, greatly changed that belief. Subsequent fossil findings further supported the idea that bipedalism preceded the development of larger brains in human evolution. 

3. The Rise Of Homo Sapiens

Homo sapiens evolved in Africa around 300,000 years ago during a period of climate change. Like other early human species at that time, we adapted to survive in unstable environments by gathering and hunting for food. Anatomically, modern humans can be characterized by our lighter skeletal build compared to earlier humans, large brains, and distinct facial features with less prominent brow ridges. 

Prehistoric Homo sapiens developed advanced stone tools, specialized them, and made more refined and complex tools like bows, arrows, and fishing equipment. Over time, we transitioned from hunting and gathering to farming and herding, leading to the transformation of Earth’s landscapes, settlements, and a marked rise in the human population.

While early Homo sapiens coexisted with other human species like Homo erectus, the Denisovans, and Neanderthals, that changed around 40,000 years ago, when we emerged as the last surviving member of the hominin family. 

2. Leaving Africa

The first humans moved out of Africa some time around 2 million years ago, though the challenging arid environments of northern Africa and Middle East initially hindered their movement. To leave Africa successfully, our ancestors had to develop physical and mental capabilities suitable for surviving in harsh conditions, where food and water were scarce and seasonal. 

The first species believed to have left Africa was Homo ergaster – or African Homo erectus – about 1.75 million years ago. An alternate theory, however, suggests that hominins might have migrated out long before that, possibly around 2 million years ago. Recent studies based on DNA analysis support it, indicating an expansion out of Africa about 1.9 million years ago, with gene flow between Asian and African populations around 1.5 million years ago. 

Regardless of the timeline, the ability to leave Africa allowed us to develop physical attributes like efficient walking, intelligence for adapting to new environments, improved tools, and a diet that included more meat, all of which would play a crucial role in human evolution for years to come. 

1. Neolithic Revolution

The rapid development of agriculture in human populations and proliferation of agriculture-based societies around the world – also known as the Neolithic Revolution – was perhaps the most decisive step in the evolution of modern humans. This pivotal transition happened some time around 10,000 BC in the Fertile Crescent region in the Middle East, leading to the emergence of the first farming communities we know of. 

The Neolithic Revolution marked a shift from small, nomadic hunter-gatherer groups to larger settlements and the birth of early civilizations. It was a time of profound and long-lasting change for our species, as this was when we first started cultivating plants and breeding animals for food, along with forming permanent communities to protect those advancements.

The causes of the Neolithic Revolution are multifaceted and may have varied across regions. One theory is that changes in the climate and a warming trend in the Middle East around 14,000 years ago played a role in the development of agriculture there, leading to the growth of wild wheat and barley in the Fertile Crescent. Intellectual advances in human societies – including the development of religious and artistic practices – also likely influenced the transition to settled farming.

In 1859, Charles Darwin published his landmark book “On the Origin of Species”. In the book, he proposed the theory of natural selection, where he stated that the body and organs of living things slowly adapt to become better at whatever they are used for while parts that have fallen into disuse become smaller before finally disappearing.

Like other plants and creatures, the human body is the result of millions of years of natural selection. The body parts we need for our survival have become specialized at what they do while the ones we do not need are gone. But what parts have we lost over time? That is what we are out to answer.

10 Fascinating Facts About Human Evolution

10 Brow ridges

Several species of early humans including the Homo erectus, Homo heidelbergensis and our cousins, Neanderthals, had brow ridges. That is, the area of their heads right above the eyes reclined backwards into the top of their heads, just like the heads of chimps and gorillas.

Today, we Homo sapiens have lost our brow ridges. Instead, we have flat faces and high foreheads that go straight upwards until they merge with the top of our heads. Why is this so?

Researchers are unsure as to why ancient humans had brow ridges or why we lost them. However, they think we may have lost them for social reasons. During a social experiment, anthropologist Grover Krantz realized that people avoided him and even crossed the streets just to avoid passing his side when he wore a Homo erectus-like facemask in public.

This indicates that brow ridges were not so friendly and had to go as humans got more social and started living in large communities. In exchange, our heads got smaller and we developed more prominent and movable eyebrows we use to pass subtle information and emotions.

9 Claws

Logic dictates that herbivores have hooves, carnivores have claws and omnivores have either claws or fingernails. Actually, all omnivores would have had claws, if it were not for primates, a group of closely related creatures that includes humans, apes, lemurs, lorises, monkeys and tarsiers.

The earliest primates had claws, which they used for digging and scratching but they lost them when they started living on trees. Now, claws are very useful for climbing trees. However, they quickly become a drawback whenever a primate wants to move from one branch to another. This was why early primates developed hands and fingernails that could climb trees and grab branches.

8 Prehensile feet

We have all probably seen a photo of an ape using its feet to grab things or hang from tree branches. Those are prehensile feet and are a defining characteristic of apes and primates. Think of them as feet that can act as an extra hand when required.

Humans are the only primates that do not have prehensile feet. We used to have them but not anymore.

The earliest humans had prehensile feet until they started walking on the ground. Their toes got straighter and firmer and lost their flexibility as they evolved for walking and running. Our first four toes lost their flexibility first and the large toe soon followed, making it our last body part to evolve.

7 Canine teeth

Man with gold front teeth, close-up of mouth

Take a peep at the teeth of chimpanzees, gorillas, orangutans and other large apes and you cannot miss those long and sharp canine teeth. We humans have canine teeth too but those are only in names. They are neither long nor sharp and are barely longer than the other teeth in our mouth.

So why do we not have long and sharp canines like other apes?

We actually used to but lost them after they fell into disuse. Like other apes, early humans developed large canines to fight other males for dominance. The prize of these fights was an exclusive mating right to several or all females in the group.

However, fights for dominance slowly fell into obscurity as early human babies got weaker and vulnerable to predators. This made human males spend more time protecting their babies than fighting for mating rights. Our canines have been getting shorter ever since and are currently the smallest that they have ever been.

6 Long arms

The earliest humans had long arms and short legs, much like today’s apes, when they first appeared six million years ago. We, in reverse, have shorter arms and longer legs. Why did this happen?

The reason is not far-fetched. The earliest humans were shorter and survived on a plant diet. This meant they required a larger digestive system and organs to process their meals. This made their rib cages expand to accommodate their larger requirements for digestion.

Things changed 1.9 million years ago when humans migrated to hotter climates and added meat to their diet. Their bodies became narrower and their digestive system got smaller since meat requires a shorter digestive tract and organs to digest.

At the same time, the legs got longer to allow them cover longer distances while seeking and chasing prey. The legs of early humans continued growing longer until the first Homo erectus appeared. They were the first ancestors of the modern human to migrate out of Africa. Their legs were spectacularly long, which helped them lose body heat.

5 Big stomachs

The human brain has gotten larger ever since the Homo habilis first appeared two million years ago. The brain of the Homo habilis was around 600 cubic centimeters. However, 1.5 million years ago, the Homo habilis went extinct and was succeeded by the Homo erectus, which had a brain size of around 900 cubic centimeters.

Researchers know our brains got larger as we got access to more food. Ironically, our stomachs got smaller around the same time. On the surface, this does not really make sense considering larger brains require more energy, which in turn, requires more food. Logically, our stomachs should get bigger to accommodate more food.

The reverse happened because early humans made the switch from a strict herbivorous diet that consisted of low quality plants to an omnivore diet that included lots of high quality meat. Their stomachs got smaller because meat packs more nutrients and energy than plants.

4 Large eyes

Some species of early humans had large eyes. This includes Neanderthals, our cousins, who freely interbred with early Homo sapiens for about 5,000 years before going extinct.

Researchers believe Neanderthals developed large eyes after migrating out of Africa to the colder parts of Europe and Asia where there was little sunlight. Their eyes got larger to accommodate more light. We Homo sapiens on the other hand, have smaller eyes because we remained in Africa where there was enough sunlight.

Curiously, there are suggestions that Neanderthal’s large eyes were a double-edged sword that may have contributed to their extinction. Researchers believe they dedicated a larger part of their brains to process information from their eyes. This meant other parts of their brains, including the parts they needed to develop complex social skills as Homo sapiens did, were smaller.

3 Tails

Modern humans grow tails in the embryo and have small tailbones after they are born. The tail and tailbone are actually the remnant of the longer tails we used to have. However, we lost those tails twice. We grew it, lost it and grew it again before losing it for a second time.

Humans first lost their tails when the Aetheretmon, an extinct fish considered the ancestor of all land dwelling creatures, lost one of its two tails.

The Aetheretmon had two tails, one atop the other. The first was a regular tail fin it used for swimming while the second was a fleshy tail it used for swimming faster. However, the fish later lost most of the fleshy tail while it kept its regular tail fin.

Millions of years later, the Aetheretmon would completely lose its regular tail fin as it evolved from a sea dwelling creature to a semi-aquatic and later, land dwelling creature. However, the fleshy tail it earlier lost regrew into the tail we see in most land animals today.

The hominids that would later evolve into apes and humans lost this fleshy tail as they started walking on two legs. Apparently, the tails would have affected their upright stance. Today, humans, chimps and gorillas do not have tails. Many monkeys have long tails but those that walk a bit more upright have shorter tails.

2 Fur

Why do humans have hair even though apes have fur? To find out the reason, we need to go back to the Australopithecus afarensis, a hominin considered the ancestor of the first humans.

The Australopithecus afarensis looked more like apes than humans. Think of it as an ape with human characteristics. It had ape-like arms, legs and fur but had a large brain and could walk upright like humans.

We lost our fur when Australopithecus afarensis abandoned the covers of the thick forests to hunt meat in the open savannah, which exposed them to more sunlight than they were used to.

However, sunlight and fur do no go hand in hand. Fur prevents sweating and traps heat, which would have caused the bodies and brains of the Australopithecus afarensis to overheat. So started losing their fur to allow them sweat and lose heat more easily.

1 Whiskers

Most mammals have whiskers but not humans. We do not have those things. Interestingly, we used to have whiskers but lost them around 800,000 years ago. To understand why we lost our whiskers, we need to understand why some animals still have them.

Animals use their whiskers to complement their eye. Every creature with a whisker actually has two kinds of whiskers: a long whisker and a short whisker. Animals use the long whisker to find their way in the dark and around tight spaces while the short whisker is reserved for recognizing objects.

However, we humans lost our whiskers after we transferred the jobs of both whiskers to other parts of our bodies particularly our fingertips, lips and genitals. Those parts are sensitive, just like whiskers, because they take in information from our surroundings and pass them over to our brains.

10 Evolutionary Advantages Of Seemingly Weird Body Functions

New species evolve from their predecessors, right? This lovely process isn’t new and is usually related to Charles Darwin’s theory of natural selection.

Natural selection is when a species is better able to adapt to its environment, diet, predators, mating, etc. This ability to adapt makes a species have a better chance of survival and eventual reproduction. The same ability to adapt is passed from offspring to offspring, ultimately changing the original species to a new, more evolved creature. Unfortunately, those species that are unable to adapt die. So, the moral of the story, change is good!

While we can all agree that natural selection takes place, we may have different ideas on what’s considered normal or weird when it comes to evolution. Normal is boring, so let’s examine some of the weirdest products of evolution!

10 The Blobfish

They say beauty is in the eye of the beholder, but in 2013, the environmentally adapted blobfish was voted ‘World’s Ugliest Animal,’ a title it still holds to this day! Sorry, blobfish. Despite its looks, the blobfish is a well-adapted deep-sea predator. It sits in wait for its dinner, snatching up any tasty-looking treats that happen to swim by.

As an opportunist, the blobfish will gobble down most anything. Its flabby body and sagging features deceive us as being weak. However, the animal’s jaws are extremely strong, and that less-than-beautiful exterior seems to be a good defense against predators such as the octopus.

David L. Stein, a former Ichthyologist at Oregon State University, recalls the 19 blobfish he’s had the dubious honor of dissecting. Stein recalls evidence of failed octopus attacks as shown by the sucker marks all over the blobfish skin.

Beautiful or ugly, weird and wonderful, the blobfish is for sure!

9 The Sea Cucumber

Sticking with the underwater theme for a moment more, we have another one of evolution’s weird creatures – the sea cucumber!

Imaginatively named for its shape and size, the sea cucumber will set you back a little more than its namesake. Having been eaten as a delicacy in Asia for centuries, it wasn’t until the 1980s that the West took a fancy for the strange-looking echinoderms.

Now, due to overfishing and its appeal for food and medicine ingredients, the sea cucumber is expensive and rarer than it was before. They aren’t exactly fish as we know them, but distant cousins of starfish and urchins. So please, let the sea cucumber be!

8 The Lungfish

They say that we mere mortals all began as creatures of the deep, eventually having crawled onto the surface of the Earth, developing limbs to walk and mouths to talk. A necessity of any land animal is, of course, the ability to take oxygen from the air into our bodies. Fish, too, require oxygen to live but take the oxygen from water.

Nature, however, has given the 300-million-year-old, aptly named lungfish the tools to take oxygen from both water and air to breathe. A lungfish has both lungs and gills!

The lungfish is a further example of how environmental factors cause species to evolve. Native to Africa, South America, and Australia, the lungfish live in swamps and rivers; but unfortunately, some dry out with drought. Droughts often mean death for many of the environment’s creatures. But not the lungfish! The lungfish is able to breathe on land and underwater. When needed, the lungfish burrows into the mud and, with its own mucus, makes itself a capsule in which it waits for the drought to end and water to return.

Who knows when or if the lungfish will evolve to become fully-fledged landlubbers like us humans, but 300-million years in the making suggests they’re happy just the way they are!

7 Water Bears

Water bears, or tardigrades, to give them their scientific name, are microscopic creatures found anywhere from volcanoes to mountain tops. They are seemingly indestructible, even able to survive in space!

Water bears were taken up by Elon Musk’s SpaceX shuttles. NASA thought it was worth their while to observe how the tiny creatures cope with life in space with the hope of learning something we can use to make our future extra-terrestrial adventures easier!

6 Venus Flytrap

When we think of nature’s predators, our first thoughts aren’t of a plant. There are, however, few more famous ‘jaws’ than those of the Venus flytrap. Despite its name, the Venus flytrap mainly preys on spiders, ants, and flies. Just don’t put your finger inside its “v” shaped leaves; it will clamp down on you quicker than you can say “Venus flytrap!”

Native to the Carolinas of the United States, the Venus flytrap can be found in its natural habitat of acidic, swampy wetlands. The plant, of course, also can photosynthesize, like all plants evolved with chlorophyll molecules. Still, the Carolina soil, lacking an abundance of nitrogen, means the Venus flytrap ‘tops up’ its nutrient levels by carnivorous means. Munch, munch.

5 The Naked Mole-Rat

The naked mole-rat is native to South Africa. This burrowing fella is often referred to as a sand puppy. You might be thinking, aww, how cute! Well, no. With a long white hairless body and massive front teeth, the naked mole-rate is far from cute, despite what millennials may remember about Rufus, the naked mole-rat sidekick from Disney Channels Kim Possible. 

This cold-blooded mammal thrives in its underground environment feasting on what are called tubers. Tubers are parts of plants that store the plant’s nutrients. The naked mole-rat need only fear snakes and birds when they do come to the surface. 

4 The Flying Fox

Named for their fox-like faces, the flying fox is the biggest bat species with a wingspan of over five feet! Bats make up one-quarter of all mammals on Earth, from the smallest weighing a few grams to the flying fox, which can weigh up to 2.6 pounds. The flying fox is native to the east coast of Australia and lives in large colonies. They flawlessly evolve to suit their environment and are vital in the native ecosystem, pollinating over 50 tree species.

Bats are unusual in that they are flighted mammals. Unlike the flying squirrel or the sugar glider, they can maintain their flight and increase altitude, unlike the aforementioned ‘gliders.’ On closer inspection, the wings of a bat appear more like hands with webbing between its digits; those digits are dextrous as it picks and eats the fruit from trees.

Humans have long written the bat into spooky stories and horror movies, probably because of their mysterious nature. They are dormant during daylight hours, awakening at night to feed. Though they are big, hairy creatures of the night, we need not fear the flying fox as they have no interest in humans, and they almost certainly won’t try to drink your blood!

3 The Goliath Tigerfish

Are you ready for this one? The goliath tigerfish can be bigger than an adult man! Yikes! There’s nothing immediately weird about this creature’s appearance, that is, until it shoots you a smile. You’ll quickly notice that it has a set of 32 razor-sharp teeth equal in size to those of the great white shark. Again, yikes!

Native to the Congo River systems and Lake Tanganyika, the goliath tigerfish is Africa’s answer to the famous Piranha, just a little bigger! If all that wasn’t scary enough, these fish hunt in groups and are known to be able to leap and catch birds in flight. If that isn’t reason enough to stay out of the water, I don’t know what is.

2 Poodle Moth

Discovered in Venezuela in 2009 by Dr. Arthur Anchor, the poodle moth is undoubtedly far from the most monstrous creature on our list. With six furry legs, four wings, and brush-like antennae, the poodle moth is as far from looking menacing and more cuddly. However, we don’t recommend them as a new snuggle buddy. 

Native to South America, the diet of the poodle moth is made up of nectar, herbaceous plants, fruit juices, and even the more nutritious contents of animal dung!

Almost Pokémon-like in its appearance, this cute little bug is nothing to fear.

1 The Tarsier

Only 10 to 15cm and 150 grams when fully grown, the tarsier gets its name from its elongated tarsal bone or heel bone. Any one of the eight tarsier species can be found in the jungles of the Philippines, Malaysia, and Thailand. 

The tarsier’s eyes are half the size of its head (and the biggest in ratio to any mammal), and the smallest of the species is the Pygmy Tarsier, weighing only 57 grams and until recently thought to be extinct.

Despite its somewhat sloth-like appearance, the tarsier is anything but slow! The tarsier is able to jump over 40 times its body length and is a ruthless predator! It jumps from tree to tree, hunting anything from bats to lizards, and is the only entirely carnivorous primate – not so cute, right?

Evolution is a remarkable process. Any life form from lowly sponges to massive whales can show evidence of how the process of adaptation has worked to its benefit over many long generations. Sometimes an adaptation works so well it becomes a defining characteristic of every branch of that life form’s family tree. Other times they probably fail miserably and die out. But the truly interesting thing is when evolution rolls the dice on something a second time. Some trait, some adaptation, that arises in one life form and then a totally separate life form that is barely related, if at all, evolves similar traits independently. And it happens more than you’d think. 

10. Things Keep Evolving into Crabs in a Process Called Carcinization

Science has bad news if you’re not a fan of multi-legged creeping life forms that skitter about and have claws. Nature wants everything to be a crab. In fact, nature wants things to be crabs so much we have a word for it – carcinization. That’s the process of a creature that is not crab-like evolving into something that is crab-like and it keeps happening.

While we need not fear that we’re going to turn into crabs one day, the process does seem to affect creatures that started life in the general sort of “crab-like” space. Which is to say crustaceans that are like lobsters or hermit crabs, ones that are not crabbed shaped initially, do evolve towards crabs. It has happened three times in a group of crustaceans called anomurans. What they evolve into is not technically a true crab, it’s not like they can change species, but they become crab-like in appearance.To a layperson, the sort of rounded shaped shell, the many legs and possibly claws as well would make you think you were seeing a crab.

King crabs, those staples of buffets around the world with their long legs, are an example of this. A king crab is not a true crab, but an anomuran decapod. Its ancestors were actually hermit crabs. Hermit crabs have to use the shells of other sea life as they have a very soft exoskeleton, so the evolution to a king crab, which does have a sturdy skeleton, is fairly dramatic. Other examples include porcelain crabs and hairy stone crabs which are also not “true” crabs. But their journey towards crabdom has been independent and a very unusual example of convergent evolution.

9. Pitcher Plants Have Evolved Independently at Least Six Times

Pitcher plants often fascinate people more than the average garden flower if for no other reason than they’re carnivorous. The idea of a stationary life form feeding on other life forms is unique. Or it seems like it should be. However, evolution seems to enjoy this concept greatly. So much so that pitcher traps have evolved totally independent of one another at least six different times. These plants are from different families entirely including Bromeliaceae, which is where you’ll find pineapples.

Unrelated lines of carnivorous plants are most prominent in three families. These plants are not to be mistaken with a Venus flytrap, which catches prey with a different mechanism. Instead, pitcher plants are defined by evolving a sort of cup that contains a digestive fluid. Insects or other sources of nutrients fall into the cup, often thanks to the slippery outside which evolved independently in most species, and fall in. Methods of attracting, holding, and digesting prey are remarkably similar across numerous species, even though they are from decidedly different biological backgrounds.

8. Three-Toed and Two-Toed Sloths are Not Closely Related

The internet loves a good sloth video and why not? Sloths represent an optimal life to many people. They relax, take it easy, eat and sleep. That’s enviable in its way. And we even have two sloths to choose from, the three-toed and the two-toed variety. While both of these creatures are known for being extremely slow, living in trees, and hanging upside down it’s also obvious that, from the outside, they do not look all that similar. 

The two-toed sloth is the shaggier of the pair and related to the giant prehistoric sloth called Megalonyx and Mylodon darwinii. Three-toed sloths are more closely related to Megatherium. But like the three-toed sloth, the two-toed has evolved to live, upside down, in trees, even though none of its large ancestors did. And that means this tree-based living is a defining characteristic of both species that evolved independently. If the two species even shared a common ancestor, scientists aren’t sure of when it may have been or what the creature was. Their best guess is that if there was one, it was definitely not hanging around in trees.

7. Falcons are More Closely Related to Parrots Than Eagles

A lot of people are frightened of birds and Alfred Hitchcock was well aware of this. It doesn’t help much when scientists are out here telling us that dinosaurs turned into birds so essentially every chicken is a tasty T. Rex. 

In the world of birds, some are definitely more intimidating than others. The birds of prey are naturally intimidating thanks to their flesh-rending beaks and claws. Hawks, eagles and falcons all seem to have speed and fury on their side. But the unusual thing here is that falcons are not the same as those other two. Despite how easy it is to mistake a falcon for a hawk, the two are only distantly related and another example of convergent evolution at work.

Rather than being closely related to eagles, falcons are actually much closer to parrots. The fact that a peregrine falcon, literally the fastest creature in the world, is closer to a parakeet than an eagle seems somehow wrong.  Despite that, DNA evidence proves that the common ancestor of the two birds has them much more closely related to each other than other birds of prey.

6. Humans and Cephalopods Have Eyes That Are Very Similar

Every year it seems that new research further proves that octopuses are remarkably intelligent animals and we’re doing a great disservice to them by ignoring that fact. It’s not just their brains which are unique, however, pretty much everything about octopuses as a species is remarkable. Take their eyes, for instance. They operate in a way very similar to human eyes but very obviously evolved in a totally independent way. The same thing can be found in other cephalopods like squid. Somewhat more remarkable is that the same genes are responsible for the eyes in both us and them. 

There’s a gene called Pax6 which is responsible for the basic construction of eyes in nearly every creature. It is found in a massively diverse number of animals which means it predates evolutionary diversification. So it goes back over 500 million years. Think of it like a control gene that governs how an eye is formed – that can be a compound insect eye, a lizard eye, a bird eye and so on. But when it comes to humans and cephalopods, it formed a very similar structure for each, what we call a camera eye. There’s a lense, an iris, a fluid filled interior, and so on. And across 500 million years and two species, one on land and the other in the sea, convergent evolution allowed for the same basic structure to come about in both.

5. New World and Old World Vultures are Not Closely Related 

There are 22 species of birds called vultures in the world. You can typically recognize a vulture as a fairly large bird, usually bald, and prone to eating carrion. In general, they seem a little gross by human standards, what with their heads buried in rotten carcasses all the time, but they do provide a great service by cleaning up all that toxic, bacteria-laden meat so don’t be too hard on them. 

Those 22 bird species can be broken down a little further as Old World and New World, meaning vultures found in Europe, Africa and Asia, and then ones found in North and South America. Despite the remarkable similarities between New and Old World species, there are genetic differences which indicate many of these birds evolved convergently. 

Old World vultures seem to have evolved from birds of prey, they’re an offshoot of the raptors. However, New World vultures can trace their ancestry to storks.

4. Six Different Lines of Electric Fish Evolved Separately

There are a lot of unique and even terrifying creatures in the sea. One of the most unusual is the electric eel. They can generate up to 500 volts (some say 600 volts) at one amp of current. But this is not the only electric fish. And others that have the same ability are not related to the eel. In fact, electric fish evolved independently in at least six different instances. These animals all make use of the same genes, they just happened to do it all over the world in different times and places.

While eels live in freshwater, electric rays can be found in the Atlantic ocean. Like all rays they are wide and flat and nearly the exact opposite of an eel in appearance. But their electrical generating abilities are very similar. And because we know most fish don’t have the ability to generate electricity, the idea of a common ancestor among the diverse electrical species doesn’t make sense. The ability came about uniquely and independently. It just did so a half dozen times.

3. Sugar Gliders Are Not Related to Flying Squirrels

Sugar gliders and flying squirrels are two of the most delightfully weird little mammals you’ll find in the treetops. Both have wide flaps of skin under their arms that allow them to glide from branch to branch, both have long tails and big eyes and if you didn’t know a lot about either species, you’d probably have no idea how to tell them apart with just a cursory inspection. 

Remarkably these similarities are very superficial. Sugar gliders are marsupials and raise their young in pouches while flying squirrels are not. While there are 50 species of flying squirrel in the world there are just 6 sugar glider species and they are native to Australia. Like most other marsupials, they evolved isolated from creatures like the flying squirrel making their similarities an example of convergent evolution. The flying squirrel is actually more closely related to primates than it is to sugar gliders. 

2. Humans and Koalas Have Remarkably Similar Fingerprints

Koala bears are perhaps Australia’s most memorable residents, right up there with kangaroos but arguably more popular thanks to their adorable appearance. Cute as they are, you’d never mistake a koala for a human because, well, they’re two-foot tall gray bears that live in trees. Koalas are marsupials and most closely related to wombats, opossums and, yes, kangaroos. However, in a case of very unique convergent evolution, their little marsupial fingers feature fingerprints that are so close to human fingerprints even experts may have trouble telling them apart at first glance. 

To find a common ancestor between humans and koalas you’d need to go back about 100 million years, well before even the T. Rex walked the earth. Nonetheless, their fingerprints look and potentially work the same as humans. Since koalas only eat eucalyptus leaves, and even then only certain ones, it’s very likely that tactile function is important to help choose the right leaves and those fingerprints come in handy. They need precise grip and sensitivity, much like humans, so it seems their fingerprints evolved along a similar path as ours.

1. Bats and Dolphins Have Nearly Identical Echolocation Abilities

Bats and dolphins are about as different as any two mammals in the world can possibly get. Yet despite their incredible differences there is evidence to show that convergent evolution was at play in both species to develop their remarkably similar echolocation abilities. 

In analyzing several bat species as well as dolphins, scientists discovered similar genetic signatures in 200 genomic regions related to echolocation. The researchers were expecting only to find 10 to 30 genes in common. When they looked at bats that didn’t use echolocation, none of these genetic similarities occurred. 

In specific, a mutation in a protein called prestin that affects how hearing works has occurred in both bats and dolphins. That this mutation could occur in two greatly different species and have the same outcome was not expected and has shown that convergent evolution goes far beyond those physical adaptations we see on the surface and includes genetic adaptation as well.