Curious children: why do animals have tails? | Kiowa County Press

Dogs use their tails to communicate.
Eastimages/Moment via Getty Images

Michael A. Small, Binghamton University, State University of New York


curious children is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected]


Why do animals have tails? – Kristin M., 11, Kansas City, Mo.


Scientists have found fossils of tailed animals dating back hundreds of millions of years. At the time, the first fish used their fan tails as fins to swim across the oceans and escape predators.

As these fish have evolved into creatures that lived on land, their tails also began to change.

Whether belonging to reptiles, insects, birds or mammals, tails serve a wide variety of uses. Modern animals use their tails for everything from balance to communication and finding mates.

Help with balance and movement

Scientists believe dinosaurs, including Tyrannosaurus rex, swayed their tails side by side to balance their heads and heavy bodies walking on two legs. This movement allowed them to run fast enough to catch their prey.

Similarly, kangaroos today use their tails to balance themselves when hopping across open land. But they don’t just use it as a counterbalance to their weight – the kangaroo tail also functions as a powerful third leg that can help propel them through the air.

Cats and other climbing animals often have bushy or long tails that help them balancea bit like a tightrope walker holding a long pole.

Monkeys use their long tail for balance while swinging through the branches of the trees in the forest. Many have prehensile or gripping tails which act as hands and allow them to hold the branches of trees.

These tails are so strong they can even hold the animal while it eats fruits and leaves.

A Tyrannosaurus rex could swing its heavy tail to balance itself while walking.

A defensive mechanism

The tails of other animals turned into weapons. For example, rays have a trademark dart tail they can use them as a defense when a predator attacks them.

Poisonous rattlesnakes have pimples of dried skin on their tails that make a racket when they shake it. This alerts any animals that may threaten the rattlesnake that it is preparing to strike.

Many insects also have tails, but they evolved separately from other backbone animals, such as fish and mammals. Most tailed insects use their tails to lay eggs or to sting and paralyze hosts or prey. In some animals, such as wasps, their tails can do bothbecause some parasitic wasps will lay their eggs inside a host.

Grazing animals, such as the North American bison, the wildebeest and the giraffe in Africa, have tails with tufts of long hair that can be given up like a whip to chase away mosquitoes and other insects that might bother them. Domestic cows and horses also have this kind of tail.

A brown rattlesnake waves its rattle in the air
Rattlesnakes have tails that evolved for defensive purposes.
Paul Starosta/Pierre via Getty Images

A communication aid

Birds use their feathered tails both to balance themselves when sitting on a tree branch and to steer and reduce drag flying. Some birds also use their tails as a courtship display.

This visual display is most remarkable in species such as turkeys and peacocks: Male turkeys and peacocks will spread their colorful tail feathers to attract females.

Animals that live and hunt in groups or packs, such as wolves, use a variety of tail positions to indicate their rank.

Dogs, which are descended from wolves, also use their queues for communication. You’ve probably seen dogs wagging their tails. when they are excited.

Why don’t you have one

Even though humans don’t have a long gripping tail like monkeys, or a thumping tail like peacocks, our ancestors had tails.

Scientists think these tails disappeared from our human ancestors around 20 million years ago. Once they started to walk upright, they no more tails to help balance more.


Hello, curious little ones! Do you have a question you would like an expert to answer? Have an adult send your question to [email protected] Please let us know your name, age and the city where you live.

And since curiosity has no age – adults, let us know your questions too. We cannot answer all questions, but we will do our best.

The conversation

Michael A. SmallEmeritus Professor of Anthropology, Binghamton University, State University of New York

This article is republished from The conversation under Creative Commons license. Read it original article.

About Florence M. Sorensen

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