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Scientists Discover The Fascinating Reason We Don’t Have Tails

Stages of human development towards shading tails.
Stages of human development towards shading tails. Screenshot from Did You Know: Why Don't Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

You have probably noticed that humans do not have tails like many other animals, but have you ever wondered why? Scientists think it may be because of our unique evolutionary history. Let’s learn more!

Why Animals Have Tails

The sacrum is left over from when we had tails.
The sacrum is left over from when we had tails. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

Tails serve various functions in animals, such as balance, communication, and defense. For example, monkeys use tails for balance when climbing trees. However, humans have evolved different ways to perform these functions.

Evolutionary Background

The Alu gene mutation.
The Alu gene mutation. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

Millions of years ago, early ancestors of humans had tails. Over time, as our species evolved, the need for tails diminished as we spent more time living on the ground than in the trees. This led to the gradual disappearance of tails in humans and the move from walking on four legs to walking on two.

The Development of the Coccyx

What the human skeleton might look like with a tail.
What the human skeleton might look like with a tail. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

The coccyx, or tailbone, is a small, triangular bone at the base of the human spine. It is a remnant of the tail that our ancestors once had. Although it no longer serves a purpose, it is a vestigial structure that provides insight into our evolution and links us to our ancestors.

Genetic Factors

Where the mutated genes were stored.
Where the mutated genes were stored. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

Certain genetic changes have contributed to the absence of tails in humans, specifically the alu mutation shown above. This mutation occurred millions of years ago and can now be clearly identified in the creatures that have it. Passing down these mutations through generations is what led to the evolution of tailless humans.

Evolutionary Advantages

Later stages of human development.
Later stages of human development. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

Not having a tail provided evolutionary advantages for early humans. For instance, it helped with upright walking and running, which were important for survival. Additionally, not having a tail allowed for more complex social and physical behaviours. Fast forward to today, and I’m glad I don’t have a tail as I’m sure I’d only find a way to trip over it!

Comparison with Other Primates

Animals with and without the Alu mutation.
Animals with and without the Alu mutation. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

Unlike humans, many primates still have tails. These tails are essential for their arboreal lifestyles, providing balance and grip for animals such as spider monkeys or gibbons. The loss of tails in humans marks a significant divergence from these primate relatives, making it hard to believe we are even related to these animals.

Rare Cases of Human Tails

Where our tails were once located.
Where our tails were once located. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

Although rare, some humans are born with small, benign tail-like structures. These are usually removed shortly after birth so that they don’t cause problems in the baby’s life further down the line. These cases, although rare, highlight the remnants of our evolutionary past, which is pretty cool!

The Importance of Upright Posture

What the human skeleton might look like with a tail.
What the human skeleton might look like with a tail while standing tall. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

Upright posture is a key factor in why humans don’t have tails. As early humans began to walk on two legs, tails became less necessary. This change in posture led to the gradual reduction and eventual loss of the tail. If you’re anything like me and slouch all the time, this is a good reminder to sit up straight! In fact, are you slouching while you read this?

Tails in Human Culture

Studying gene mutation.
Studying gene mutation. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

While humans don’t have tails, they often appear in myths and folklore. Tails are sometimes depicted as symbols of animalistic traits or supernatural powers. This shows how the idea of tails has persisted in the human imagination, even if mostly in movies or comics.

Ongoing Research

Ancient bones showing were our tails would have been.
Ancient bones showing were our tails would have been. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

Scientists continue to study the genetics and development of tails in humans and other animals. This research helps us understand more about evolution and developmental biology. By studying tails, scientists can learn more about the complexities of human development and narrow down exactly how we came to be how we are today.

Conclusion

The gene mutation loop that got rid of our tails.
The gene mutation loop that got rid of our tails. Screenshot from Did You Know: Why Don’t Humans Have Tails? Source: YouTube Channel: Encyclopaedia Britannica

The absence of tails in humans is a fascinating aspect of our evolutionary history. It reflects how our species has adapted and changed over millions of years. Understanding why we don’t have tails offers insight into the broader story of human evolution!