Why humans don't have tails. Genetic basis for our tail-loss evolution.

Unlike our domestic cat companions we don't have tails. You've probably noticed! 😉😎 But we might have had tails and think how different the world would be if we had retained our tails like our primate cousins. The mind boggles. One's imagination can run riot with that image. All the chairs and all the sofas and all the seats on trains and buses would have to be changed.

Human with a tail in X-ray. Image by DALLE.

RELATED: Evolution of the blotched tabby pattern of domestic cats.

So what happened? Well, firstly, unlike Tucker Carlson, you've got to believe in evolution to believe in this scientific explanation. In fact, I hope Carlson reads this article because it might make him see sense about evolution. He believes that God created humans and animals under the creationist theory. He says there is no evidence for evolution which is wrong but he believes creationism about which there is certainly no evidence whatsoever. Tucker Carlson is irrational.

"It has long been speculated that tail loss in hominoids contributed to orthograde and bipedal locomotion, the evolutionary occurrence of which coincided with the loss of the tail" - quote from the study - see citation at base of page.

The reason

In summary, a genetic parasite altered a crucial gene related to tail development when our lineage diverged from other primates around 25 million years ago. This alteration ultimately led to the disappearance of tails in apes, including humans. Our tailless state owes its existence to this ancient genetic twist.

In some more detail: over millions of years, DNA undergoes changes that drive evolution. One intriguing element is the Alu element, a repetitive DNA sequence found exclusively in primates. These “jumping genes” can insert themselves randomly into the genome, potentially disrupting or enhancing gene function. In this case, the Alu elements reside in the TBXT gene, specifically within introns (DNA sequences flanking exons). Introns were once considered the “dark matter” of the genome, assumed to serve no purpose. However, when cells use the TBXT gene to generate RNA, the repetitive nature of Alu sequences causes them to bind together.

The researchers discovered two Alu elements in the TBXT gene, present in great apes but absent in monkeys. Remarkably, these elements reside in introns, not in the protein-coding exons. When RNA molecules are generated from the TBXT gene, the Alu sequences bind together, potentially influencing tail development.

Now, that is highly technical and I don't fully understand it but that is the current explanation as to why humans don't have tails. You can boil it down to the way evolution works and the way genetic mutations sometimes arise during evolution which leads to the creation of a different kind of animal and that animal does very well in terms of survival and therefore this alteration to the appearance and physiology sticks around and doesn't disappear.

Bo Xia, is the first author of the study (formerly a graduate student at New York University and now a principal investigator at the Broad Institute).

RELATED ARTICLE: Feline Evolution in Brief.

Study Citation

Xia, B., Zhang, W., Zhao, G. et al. On the genetic basis of tail-loss evolution in humans and apes. Nature 626, 1042–1048 (2024). https://doi.org/10.1038/s41586-024-07095-8

P.S. please forgive the occasional typo. These articles are written at breakneck speed using Dragon Dictate. I have to prepare them in around 20 mins.

Tucker Carlson rejects evolution and believes God created us (creationism)

Tucker Carlson is the American commentator and writer who made a fool of himself when interviewing Putin. He was so obviously sycophantic, looking up to the Almighty Putin, Czar Putin as if he were some sort of God. It was embarrassing but it did show the sort of attitude he has about life generally. He clearly thinks Putin is a wonderful leader and probably doesn't object to Putin's illegal invasion of Ukraine.

It's now come to light that Carlson does not believe in the concept of evolution as espoused by Charles Darwin. Darwin's theory of evolution (of natural selection) is almost universally supported by scientists of all colours and persuasions and by the vast majority of educated people who are not religious fundamentalists.

On cell phones click the image to see it larger....

It seems that Tucker Carlson is a kind of religious fundamentalist because he believes that God created animals and humans as per the story in Genesis. No doubt he believes that humans have dominion over animals and can use animals as they wish. This means that they can abuse animals and do whatever they like because animals are there to serve humans. I expect Carson to think those sorts of thoughts.

The man is, in my honest opinion, deluded and needs help. He says there is no fossil evidence that humans have ultimately evolved from single celled protozoans over billions of years.

I think he's correct in that you can't trace a line of fossils all the way from single cell creature to highly complex human. But fossil records provide ample support of evolution. I'm not a specialist about evolution but there is all kinds of scientific evidence which supports the theory.

Here's some evidence summarised:

1. Biogeography: Darwin observed closely related species inhabiting the same or adjacent territories. This distribution pattern suggested that these species likely descended from a common parent species. The geographical distribution of organisms provided crucial evidence for evolution.

2. Paleontology: Fossil records revealed a sequence of life forms over time. Transitional fossils, such as Archaeopteryx (a link between reptiles and birds), demonstrated gradual changes between species. These fossils supported the idea of common ancestry and gradual evolution.

3. Embryology: Comparing the embryonic development of different species revealed similarities. For instance, vertebrate embryos exhibit common features early in development, even if they diverge later. These shared developmental patterns indicated evolutionary relationships.

4. Morphology: Darwin studied anatomical structures across species. Homologous structures (similar features due to shared ancestry) provided evidence for evolution. For example, the pentadactyl limb (with five digits) appears in various vertebrates, including humans, whales, and bats.

5. Molecular Biology: DNA and genetic codes reflect shared ancestry. Comparing DNA sequences among species reveals evolutionary relationships. Similarities in genetic information support the concept of a common ancestor.

In summary, Darwin’s theory of evolution is supported by direct observations, homologies, fossils, biogeographical patterns, and molecular evidence.

Back to Carlson...

Carlson says that because we talk of Darwin's theory of evolution that it still remains a theory meaning not proved but he is wrong because in this instance, using the word 'theory' in a scientific context, means that it is solidly supported by evidence and hard science.

Tucker Carlson.

Image credit: By Gage Skidmore from Surprise, AZ, United States of America - Tucker Carlson, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=135028856

Respecting Creationists

Of course, I respect the views of others. I respect the views of religious fundamentalists. They have a right to believe what they want to believe. But they are wrong about evolution and about God creating humankind. Religion is a creation of humankind as it makes life more palatable.

Believing in a God

Believing in a God is very helpful in life. No question about it. My mind immediately turns to the number one golfer in the world currently Scottie Scheffler. He is religious and he firmly believes in God. He uses his religion very productively in his golf. It helps to keep him calm and better cope with the pressures of playing professional golf.

His attitude and mentality when playing golf tournament are second to none. They are underpinned by his religious beliefs. Believing in God takes away a lot of the pressure when playing a tournament because the outcome is taken from the golfer and placed into the hands of your God. 

When you hear Scottie Scheffler talk he does so incredibly calmly as he has handed over his life to God which is very calming. Believing in a God removes a lot of the anxiety that one is bound to experience in our day-to-day lives and more so for a professional sportsman when competing.

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P.S. please forgive the occasional typo. These articles are written at breakneck speed using Dragon Dictate. I have to prepare them in around 20 mins.

The domestic cat is NOT weird as stupid newspaper journalists claim

Online newspaper journalists have a tendency to claim that the domestic cat is "weird". It just plain stupid. Domestic cats behave as they instinctively have evolved to behave. They behave differently to humans and from a cat's perspective, no doubt humans behave weirdly. 

In fact human behaviour is far more weird than cat behaviour. Look at what humans are doing to the planet at the moment? They are destroying the planet upon which they rely for sustenance and for all their needs. If that isn't weird I don't know what is.

But a website called Your Tango says that cats are weird and they list 15 facts to prove it. So what are these facts? I will touch on a few of them to illustrate my argument.

Perspiration

The first one they list is that "cats sweat through their paws". What is weird about that?! That's perfectly normal. Cats can't sweat through their bodies because they have a coat which is highly functional. And they keep their coat clean all by themselves without having to go into the shower! Far more practical than human behaviour. 

Also when they groom themselves it helps to cool them through the same scientific process which makes sweating effective: the latent heat of evaporation.

Tasting sweetness

And they add that "cats can't taste anything sweet". So what? Cats are obligate carnivores. They've evolved to eat meat. They don't need to be able to taste sweetness. 

Look, if humans couldn't take anything sweet just like cats there would be much less human obesity. Around 40% of Americans are obese. It is a similar percentage UK residents. This obesity is nearly always caused by overeating and eating the wrong foods including foods high in carbohydrate i.e. sugars. Sugars and salt are addictive to humans.

Ironically, the only reason why domestic cats can be obese (and there are too many obese domestic cats thanks to poor human caregiving) is because of the high carbohydrate content in the unnatural dry cat food that they are given so often. Humans have passed on their obesity to the domestic cat.

Grooming exaggeration

Then Your Tango begins to get things wrong. They add that "cats spend up to half their lives grooming themselves". Wrong! Completely wrong! Cats are fastidious groomers but they don't spend half their lives grooming themselves.

Sleeping exaggeration

And they say that cats spend 70% of their lives sleeping. This is incorrect as well because cats, particularly full-time indoor cats, spend a lot of their time perhaps even more than 70% sometimes of their lives not sleeping but snoozing. That's because they've nothing to do thanks to full-time indoor living and a sterile environment. They are not sleeping in the proper sense. We know this because they leap into action at the slightest activity near them.

DNA

The journalist also adds that domestic cats shed 95.6% of their DNA with tigers. That's probably correct and there is also nothing weird about it at all. It's what you would expect because thanks to millions of years of evolution both the tiger and the domestic cat stem from the same ancient cat-like animal. 

Their evolutionary paths split millions of years ago but their ancient origins are the same. Nothing strange about that. It is all nature, evolution and scientific.

I won't bother to go on because I'm wasting my time. I've made my point. Online journalists need to be more careful and stop using click bait words and tactics. I've seen too much of it; too much stupidity and carelessness.

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P.S. please forgive the occasional typo. These articles are written at breakneck speed using Dragon Dictate. I have to prepare them in around 20 mins.

Menopause is a mystery and Ngogo chimpanzees make it more of a mystery!

Elderly Ngogo chimpanzee. Image: Sci News.

In terms of the evolution of animals as per Charles Darwin's theory of evolution, which is very widely accepted nowadays, the menopause of a number of primate species and of humans is somewhat of a mystery.

Perhaps you are like other men (including me) in not really thinking much about the female menopause and its purpose - some people think that the male human can also have a menopause. What I mean is why does it happen? What's the purpose of the female menopause?

It cuts short a female's ability to procreate and procreation is important in terms of the survival of the human and some primate species and their evolution. The more people there are the more chances there are of creating better people in terms of their genetics and survival.

The answer may be that after the menopause, a female becomes a grandmother and the grandmother can help raise the offspring of their daughters and sons - the 'grandchildren'. In other words, the Ngogo chimpanzee grandmother becomes a grandmother like a human grandmother and helps to raise the kids as it is very demanding.

Without the menopause there would be no 'useful grandmother' to carry out this function. This is called the "grandmother hypothesis".

My research on this also tells me that Ngogo chimpanzees live long lives of about 33 years which is about twice as long as that of other chimpanzee communities and within the 27–37-year range of life expectancy at birth of human under-gatherers.

However, the research today as published in the Times states that grandmother Ngogo chimpanzees do not get involved in raising the 'grandchildren'. In a new study, the researchers looked at 66 females and they estimated that these females spent 20% of their life unable to reproduce as like humans they have the menopause but unlike humans "they do so without lifting a finger to help with their grandchildren."

If the grandmother does not help with raising the kids as is the case with the Ngogo chimpanzees, this undermines the theory 'grandmother hypothesis' thus making the menopause a mystery to this day.

The research is published in the journal Science. And in this research, they also state that the fact that the grandmother does nothing does not totally kill off the grandmother hypothesis. It allows the grandmother to be a "doting grandmother" which may serve some use.

Another theory is that female primates of certain species have the menopause in order to make them less alluring to prevent them competing with their daughters for reproductive opportunities. We don't know at the moment.

Note: as you can see this is nothing to do with cats! I just fancied doing it as it may help some people to better understand the human female menopause.

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P.S. please forgive the occasional typo. These articles are written at breakneck speed using Dragon Dictate. I have to prepare them in around 20 mins.

Are domestic cats related to lions and tigers?

Yes, domestic cats are related to lions and tigers and all the other cats because they all started off at the same source. This is about evolution and taxonomy. But you have to go back about 40 million years to Miacoids (miacids) which appear to be the first cats on the planet although they did not look like modern day cats. 

Tiger and domestic cat. Collage: PoC.

It is currently believed that from that start all the cat species evolved in different places and at different times. Miacids evolved into the Proailurus (a civet/cat creature) and that creature evolved into prehistoric cats which walked on their toes like modern day cats. 

An example was a species called Pseudaelurus. This creature was the size of a modern-day cat. It evolved into two main groups one of which was Schizailurus which in turn evolved into the Felidae (the family of cats). Martelli's cat was a species which inhabited Europe about 2.4 million years ago and which is believed to be the ancestor of today's wildcat, a species of cat which is still present in Europe. Apparently the first modern day cats were cheetahs.

Cat history from the start to modern day. Cat History For Kids. Credits: Landscape of N.America 10m years ago Wikimedia Commons author Jay Matternes. In public domain USA. Fair use pleaded. Pseudaelurus in public domain USA and fair use pleaded. USA 1945 by army.arch creative commons. Snowshoe cat copyright Helmi Flick. Note: there is one small deliberate mistake in the picture. Can you spot it and leave a comment?

You have to believe in evolution to believe that domestic cats are related to lions and tigers. But science supports evolution. It is through evolution that domestic cats are related to lions and tigers. Domestic cats are very, very similar in every respect to lions and tigers. There is not much difference which is apparent because they both look like cats! There's a massive size difference but the domestic cat, in its mind, thinks just like a tiger or lion. And their behaviour is incredibly similar. That alone tells you that they are related.

If you want to know a bit more about big cat history you can click on this link. And I cover the evolution of the cat species in a simplified way on this page (click link please). The science of taxonomy which is the classification of the species is evolving itself. It was enhanced through scientific knowledge of DNA. Before DNA scientists simply observed an animal undecided whether it was similar to another animal and therefore classified it as part of a species or subspecies. That proved to be imprecise whereas DNA testing is very precise because it gets to the core of the issue.

Do tigers live in the Amazon rainforest?

Categorically no, tigers do not live in the Amazon rainforest! The big cat which is the top predator in the Amazon rainforest is the jaguar, which is not much smaller than the tiger. Why are there no tigers in the Amazon basin? It's just a question of evolution. The tiger was first created through evolution in Asia and I guess there was no landmass connecting Asia with the Amazon basin millions of years ago and therefore there was no possibility for the tiger to migrate across that landmass to what is now South America.

Elusive Bengal tiger in Kanha Tiger Reserve, India. Photo: in public domain.

READ MORE ABOUT THE TIGER

It is the same reason why there are no wild cats on the Australian continent. It's just down to a water barrier between the area where the wild cats evolved, which in this instance is the Far East, and the Australian continent. If Australia was connected to the Far East there would be a range of wild cat species living in Australia today. If there were perhaps the Australians would like feral cats more! They hate them judging by the numbers that they kill.

It is also the reason why there are no tigers in Africa and on that continent the lion is the top predator. The tiger is slightly bigger on average than the lion, by the way, but it is said that the lion can beat the tiger, on average, in a fight.

Once again, going back millions of years when the tiger first evolved into a cat which looks like today's tiger there was no possibility for that animal to migrate to Africa because of a water barrier and therefore all the tigers are in Asia beginning with India and going all the way across to China and the Russian Far East, where the Siberian tiger lives in very small numbers by the way (500).

There is a range of tiger subspecies but some have become extinct because of human activities. The Bengal tiger is the dominant species of tiger in the world but even those are limited to about 3,500 in total population size but we don't know exactly how many there are because it is difficult to count them through scats and camera traps records.

How domestic cats came to be in a nutshell

Evolution of the species. How domestic cats came to be in a nutshell. Screebshot.

Some people want to know how domestic cats evolved to where they are today. To answer the question you have to believe in Darwin's theory of evolution as set out in his book On the Origin of Species published on Thursday, 24 November 1859. If you believe in his theory as opposed to creation by a God (creationism) then you have to study the theory of evolution to fully understand it. 

Remember that life emerged on Earth 3.5 billion years ago so evolution is a slow process. That's way we have the species we have. It took millions of tiny changes. Also the first early human ancestors orginate from 3.5 million years ago.

Darwin's On the Origin of Species.

This will allow you understand how domestic cats came to be - the first part of the story. The video below explains it quite nicely I think. It is quite complicated. 

Image: MikeB.

You can click here too if you want to read about the evolution of the family of cats.

The theory of evolution explains how natural selection produced the family of cats. There are about thirty-six species of cat, one of which is the domestic cat. All the others are wild cat species. The domestic cat is essentially a domesticated North African wild cat.

Over the ten thousand years of domestication of the North African wild cat, the species evolved from being striped tabby cats to a wide range of coat types. This happened naturally and then people intervened through formal selective breeding or artificial selection since about 1850. Although there would have been some selective breeding by people on an ad hoc basis in the early development of the domestic cat as they preferred coat types.

Through artificial selection, as carried out under the auspices of cat fancy (cat breeders who create purebred cats of a certain breed for cat shows and for sale) about 104 cat breeds were created, as an absolute maximum. To these purebred cats you have to add the vast majority of domestics cats namely random bred cats. Also we must not forget the cats who should be domesticated but are feral (wild), the feral cats.

Random bred cats are still evolving through natural selection. That, in a nutshell is how domestic cats came to be...!

Why are cats' tails so long?

Are cats tails so long? It is all relative and subjective. But some cat's tails are longer than others. If the cat is a domestic cat there is no pressing reason why his or her tail should be longer than that of another cat other than the physical characteristics of the cat as dictated by his genetic makeup (genotype). There will be no demanding functional need for a long tail.

The situation is different for the wild cats. You will see long, thick, heavy and well insulated tails on cats that do a lot of high risk climbing and maneuvering. Wild cat species that come immediately to mind are the snow leopard, margay and clouded leopard.

I believe what needs to be stated is that the length of a cat's tail has been dictated by evolution over millions of years. The tail is a perfect length for the function that it needs to perform which as mentioned below is to help a cat balance when performing manoeuvres which are tricky at high elevations. For example, walking along a branch of a tree for a domestic cat or a tree-dwelling wild cat species (margay). Because evolution has a sort of perfection about it you cannot state that the tail is so long or too long or too short. It is a perfect length for its desired primary function.

RELATED: Cat Tail Up Position: Meaning and Origin.

A secondary function is as a signal to another cat that the approaching cat is friendly. This is when the tail is placed in an erect position called "tail-up". Another secondary, inadvertent function, is that it signals an indecisive mind. When the mind flicks between two possible decisions the tail follows as if metaphorically speaking it is keeping the cat's mind in balance.

Snow leopard tail - cropped image to highlight tail
You won't see a better tail. Photo: by Marit & Toomas Hinnosaar

The snow leopard has perhaps the most impressive of tails. It is far longer and thicker than anything seen on a domestic cat relative to the size of the cat. This is because the snow leopard spends a lot of its time on 40 degree rocky slopes. And the tail is needed to assist in balance. The other two are tree dwelling cats.

This requirement applies to all cats. The cheetah, a ground dwelling cat uses its tail for balance in maneuvering on the ground when chasing prey.The serval has a relatively short tail. The serval is very much a terrestrial cat.

Domestic cats use the tail for balance too, but also for body language communication. See for example: Tail up.