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Myths of Evolution: The Tail Wagging the Dog

Updated: Aug 24, 2023

If evolution is true, it does not explain the causal “for” of any evolved feature of living things.

Thorns on plants and quills on porcupines? They each evolved for the purpose of protecting the organism from predators. Right?

Wrong. One of the myths of evolutionary theory is that features of plants or animals evolved for a purpose.

The myth popular among virtually everyone is that because we can observe certain features of animals being used “for” some purpose, that feature must have evolved “for” that purpose.

Do you see the subtle shift from observation to myth?

In this popular myth of evolution we have the tail of usefulness wagging the dog of purposeless changes in nature.

Speaking of dog’s tails, we bring this topic up because we came across an interesting article from The Conversation entitled, Why do animals have tails? The Conversion’s tag line is “Academic rigor, journalistic flair,” which we like. We need more of that.

But . . . this article needs a bit more academic rigor and a bit less journalistic flair. Because in its answer to an 11-year old’s question, it propogates a poplular myth of evolution that is divorced from the academic rigor evolutionary theory demands.

The question, “why do animals have tails?” can be answered on two levels. First, as The Conversation article does well, is simply to observe that animals’ tails do, in fact, serve a purposes that can satisfy the “why” of their existence. But on another level, where The Conversation whiffs, is in explaining the why of any animal tails’ origin in the first place; why does any animal have a tail instead of no tail at all?

Existence versus origin. The fact of one seeming to have purpose feeding into the myth of the other that occurs without purpose or plan.

On the first level, The Conversation notes that we observe many tails serving some kind of purpose. For example, in answering “why do animals have tails?” they observe the following examples of tails having a function:

Scientists believe that dinosaurs, including the Tyrannosaurus rex, swung their tails side to side to balance their heavy heads and bodies while walking on two legs. This movement allowed them to run fast enough to catch their prey. Similarly, present-day kangaroos use their tail for balance when they leap across the open land. But they don’t just use it as a counterbalance for their weight – the kangaroo’s tail also functions as a powerful third leg that can help propel them through the air. Cats and other animals that climb often have bushy or long tails that help them balance, kind of like a tightrope walker holding a long pole. Monkeys use their long tail for balance while swinging through forest tree branches. Many have prehensile, or grasping, tails that act like hands and allow them to hold onto tree limbs. These tails are so strong that they can even hold the animal up while it eats fruit and leaves.

We agree that these are perfectly good answers to the question, “Why do animals have tails?” in the sense of “why might tails exist on animals?”

But The Conversation sets up these examples with a leading paragraph that implies all of these uses are the result of some need of these animals as they evolved from fish:

Scientists have found fossils of animals with tails dating back hundreds of millions of years. Back then, early fish used their fanlike tails as fins to swim through oceans and escape predators. As these fish evolved into creatures that lived on the land, their tails started to change too.

Their tails started to change? Really? Why?

The Conversation’s implies that the tails we see on fish “started to change” and ended up as all the tails we see on animals today. The natural inference any 11-year old? His dog’s tail evolved from a fish tale, er, fish tail. The inference follows that the dinosaurs tail evolved for the purpose of balancing their heavy heads. And kangaroo tails evolved for the purpose of a powerful third leg for jumping. And so on.

And here The Conversation article veers into the myth of purpose-driven evolutionary development. This article, rather than being “academically rigorous” is merely another example of the “implication/inference” technique for “teaching” of evolution. In this technique a theoretical notion is implied (fish evolved into creatures that lived on land and their “tails started to change”) and a logical result is infered (the fish tail evolved to supply some need of their respective owners).

The idea that tails on animals evolved for a useful purpose is reinforced by the reverse idea, that tails will go away when they no longer serve thier purpose. The Conversation relates about you and me: Even though humans don’t have a long grasping tail like monkeys do, or a vibrant feather tail like peacocks have, our ancestors did have tails.

Scientists believe those tails vanished from our human ancestors around 20 million years ago. Once they started walking upright, they no longer needed tails to help with balance anymore. Ibid.

The idea that features evolve in animals because they are needed to serve some useful purpose is a myth, completely divorced from evolutionary process. And the reverse idea, that tails disappear when they are no longer needed is likewise a myth, divorced from any evolutionary process.

The “why” of animals’ tails in the context of the tail’s origin can be answered very simply in evolutionary terms: Animals have tails because their DNA hardware stores coded software building instructions that execute to build a tail. And animals like humans do not have tails because their DNA hardware does not store coded software building instructions for building a tail.


A fish has a fish tail because its DNA hardware executes the coded software to build a fish tail whether it needs one or not. The fish software will never build a dinosaur tail, a kangaroo tail or any other kind of tail, whether either the dinosaur or kangaroo needs a tail or not. For a different tail on a different animal a completely different DNA coded software needs to be developed and executed. And, if an animal does not have any coded software to build a tail, it does not have one whether it needs one or not.

Evolutionary theory holds that the DNA coded hardware for dinosaurs and kangaroos evolved from meaningless, random disorder in the genome of a previous life form, such as that fish that crawled up on land. And it was not this random disorder followed no guide and proceeded without any purpose toward a tail or anything else. If an animal has a tail now it is merely the result of purposeless random changes that happened without any forethought of utilitarian benefit.

Do you see how “their tails started to change too” become a whopper of an implication when academic evolutionary rigor is applied?

Thus, the real question is not what animals use their tails for, but how did they get their tails in the first place? What is the origin of their tails? Did they really evolve from a fish tail? If so, how?

The “why” question is more properly stated as “Why do some animals have executable coded instructions to build their kind-specific, unique tails?” Or, “How did the executable software in first fish-kind to build a fish tail get reprogrammed by random genetic variation to be instructions to build all those other tails?

With the more proper framing of the question, consider the academically rigorous version of The Conversation’s quote above about fish tails that “started to change”:

As these fish, which had coded software inside them to make fish tails, evolved into creatures that lived on the land, the coded software inside them was reprogrammed over many generations to be software to build completely different kinds of tails on other completely different kinds of animals. Proper answer, Creation Reformation

Even an 11-year old can see that for the evolutionary story to hold together nature must have learned to code. If random genetic variation is the only source of reprogramming the DNA for making fish tails (and it is, if evolution is true), then what caused all the necessary order required for beneficial reprogramming?

Or, maybe fish have fish tails because the fish kind of animal was created with coded software for fish tails and dogs have dog tails because the dog kind of animal was created with coded software for dog tails.

But then, who or what did the creating?

Think about it.

For more information, see our Creation Reformation home page. Also, read Did Nature Learn to Code?


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