A-z - Animals

Why do animals have tails?

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Did you know that everyone has a tail at one time? We grow our tails in utero around 31 to 35 days old, but then our tails degenerate and fuse into our vertebrae. The place where our tail fuses is called the coccyx or "coccyx." Sadly, we can't keep tails, which is unfortunate when you stop to think about all the incredible functions tails serve in the animal kingdom.

Tails come in all shapes and sizes, from small tails with little or no function to large tails that are only half the length of the animal's body. Animals use their tails for different reasons, depending on specific evolutionary adaptations. The role of the tail varies from animal to animal, with some tails evolving for multiple purposes, while others have evolved for specific reasons. In this article, we discuss some of the main functions of tails and provide specific examples of how animals use them in the wild.

why animals have tails

River reclamation
Kai Ken with the tail up.

©Lindsay VG/Shutterstock.com

There are so many types of tails that it's impossible to say exactly how many functions the tails serve. While some tails clearly evolved to perform specific tasks or meet biological needs, the motivations behind the existence of others remain uncertain. Broadly speaking, the tail has six main functions. Although there are different functions, these six causes are the most common and widespread. The functions of the tail include balance, defense, navigation, communication, warmth or nutrition, as part of mating rituals, and to mark territory.

for balance

Are marsupials mammals?
A kangaroo uses its tail for balance and to help propel it forward.

© Benny Marty/Shutterstock.com

One of the most common reasons land animals have evolved tails is that tails help animals maintain balance. In these animals, the tail acts as a counterbalance, allowing them to maintain balance in unstable positions or move quickly and efficiently over rough terrain. For example, cats grow tails to help them maintain their balance when walking on sparse or uneven ground. Additionally, their tails help them maintain their balance when running or jumping on their prey. Likewise, kangaroos use their tails for balance when hopping at high speeds. Finally, squirrels use their bushy tails for balance when jumping from tree to tree. In these cases, the animals' tails help them move. While not essential for navigation, a tail evolved for balance could mean the difference between a predator capturing prey or prey escaping from a predator.

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as a form of defense

Rattlesnakes wag their tails as a warning to predators.

©Nina B/Shutterstock.com

Another major reason animals develop tails has to do with the tail's role as a form of defense. Animals that use their tails for protection have evolved ways to manipulate them to confuse, distract or deter predators. For example, rattlesnakes grow their tails to help them warn predators not to get too close. When the keratin chucks rub together, their tails rattle, hence the name "rattlesnakes." Meanwhile, some lizard species, such as green iguanas and bearded dragons, can part their tails to distract predators. The lizard will toss its tail aside in the hope that a predator will chase it down as an easy snack, allowing the lizard to escape quickly and easily.

Other animals follow the adage that "the best form of defense is a good offense." These animals use their tails as weapons to deter predators and repel potential attackers. For example, the tail of a stingray contains one to three poisonous barbs. Stingrays rarely attack prey with their tails, but draw them out to deter predators that get too close. Another animal with an aggressive tail is the porcupine. Porcupines rely on hundreds of sharp spines covering their bodies and tails to ward off nosy predators.

help them navigate

World's Oldest Greenland Shark
A Greenland shark uses its tail to navigate the frigid Arctic waters.

©Dotted Yeti/Shutterstock.com

For many animals, the tail is the primary means of navigation, or an auxiliary tool for more direct navigation. Animals that rely on their tails to navigate do so because they have adapted to specific environments where it is difficult to move without a tail. One of the most obvious examples of animals that use their tails to navigate is fish. Most fish use their tails to propel their bodies through the water. They generate power by flicking their tails from side to side and use torque and twist to change their direction.

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Monkeys count as another group of animals that use their tails to help them navigate. Some monkeys use their tails to grab branches, which allows them to move quickly through the forest canopy and avoid predators on the ground. The tail that evolved to grab and hold objects is called a grasping tail, and it's one of the reasons monkeys have a reputation as agile animals.

as a means of communication

Two golden retrievers running together
A dog wagging its tail can mean it's excited or happy.

© iStock.com/Ksenia Raykova

Some animals also use tails as a means of social communication. These animals use their tails to convey simple signals to friend or foe, such as warning allies of nearby danger or conveying emotions. For example, some deer species will flash white under the tail as a warning side, indicating potential danger. Likewise, when beavers detect the presence of a predator, they flap their tails against the water as a basic form of alarm. Also, as every dog owner knows, a dog's tail can say a lot about its emotional state. A wagging tail usually means the dog is excited or happy, while a flabby, drooping tail can mean the dog is unhappy or depressed.

for warmth or nourishment

Alligator with the whole body on the rock
Alligators can store fat in their tails for winter consumption.

©Danny Ye/Shutterstock.com

Sometimes, animals also use their tails to protect against bad weather. These animals have adapted traits that allow them to use their tails for warmth in cold weather. An example is the fox, which wraps its fluffy tail like a blanket around its body. Other examples include coyotes, which will curl up next to their tails to keep warm on cold nights. Meanwhile, some people use their tails as a source of nutrition. Alligators store fat in their tails for use during the lean months of winter. Therefore, a crocodile with a thick tail is a sign of a healthy, well-fed crocodile.

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As part of mating rituals or to mark territory

Bird of Paradise Courtship - (Paradisaea raggiana)
Birds of paradise use their feathers as part of mating rituals.

© Francisco Herrera/Shutterstock.com

On rare occasions, animals will incorporate their tails into mating rituals. These animals likely adapted to grow tails to help distinguish them from potential competitors for breeding opportunities. One of the best examples is certain birds, such as the bird of paradise. Males develop beautiful and delicate tail feathers, which they carefully flap back and forth to attract females. On the other hand, some animals use their tails to let other males know that their presence is unwanted. A male hippo manipulates its tail like a propeller, throwing its poo over a wide area to let other males know they are not welcome.

Frequently Asked Questions About Why Animals Have Tails

Which animals have the longest tails?

Among land animals, the giraffe has the longest tail at about 8 feet. Also, blue whales have the largest tails of any animal, reaching a length of 25 feet.

Why do some animals wag their tails?

Animals may wag their tails for a number of reasons. Sometimes, animals will wag their tails to repel flies. Other times, they may wag their tails to convey emotions, spread pheromones, or warn potential predators.


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about the author

Heather Hall

I'm a freelance writer with 22 years of experience. I live in the Pacific Northwest surrounded by nature. When I do my daily runs, I often see herds of elk, deer, and bald eagles. I have two dogs who take me on hikes in the mountains where we see coyotes, black bears, and wild turkeys.

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