Why Do Animals Have Tails?
The tail is an extension of the vertebral column, and is generally composed of vertebrae. Most vertebrates have tails but some animals do not have. These include human, gorilla or some marine mammals.
In some species the tail is prehensile and used to cling to the branches to help with travel (in some monkeys and some geckos). In other species the tail is involved in the body's balance (cats and kangaroos, for example) or traction (in crocodiles, tail swimming aid). Iguanas and lizards use it to defend themselves (like a whip), but also to climb and swim.
As for birds, the tail is made up of the tail feathers that help manoeuvres in flight. In addition to birds, the tail is an ornament of sexual seduction as in the peacock and in other species, a single secondary sexual character as in marine turtles.
In hominoids; the loss of the tail is probably related to a balance transfer to the feet and hands. Human embryos have a tail that is about one-sixth of their size. During the development of the embryo into a foetus, the tail is resorbed in the body growth. This development of a tail in humans is a residual structure.
5 Reasons Why Animals Have Tails
Have you ever wondered why animals have tails? A tail is the hindmost protrusion of an animal. It is prolonged beyond the body and is used for a variety of reasons. These reasons include defense, balance, aesthetics, locomotion and communication.
Tails have evolved over the millennia to serve different purpose for different animals. The following are the 5 most common uses of tails in different animals around the world.
Tails for grasping
Animals that are able to hold or grasp objects with their tails have developed this ability as a response to their environment. Tails that have the ability to grasp objects are known as prehensile tails. Most of the animals that have prehensile tails live in dense forests such as those found in South and Central America.
Examples of animals with prehensile tails include:
- Spider Monkeys-these monkeys live in the upper sections of the tropical rain-forests of South and Central America. They use their tails for grasping unto branches as they move from tree to tree.
- Opossum-this is the only marsupial in North America and it uses its long tail to grasp on branches for support and to free up its other limbs to perform other functions.
- Kinkajou- also found in the tropical rainforests of South and Central America, this mammal that is closely related to the racoon uses its prehensile tail as a fifth limb to grasp objects
- Harvest Mouse- is a small rodent which weighs 6 grams and lives in the fields of Europe and Asia. It uses its prehensile tail for support while foraging.
- Porcupines-found in South and Central America, this adept climber also uses its limbs to grasp while climbing
- Chameleons- have developed very strong prehensile tails that they use to grasp onto branches and twigs
Other animals that have developed tails for grasping are snakes, geckos, alligator lizards, salamanders, seahorses and pipefish.
Gecko Steering With Tails
Tails for Steering
Animals such as cheetahs have long tails that they use for steering in different directions when running very fast during hunting. The tail of the cheetah works as a rudder to assist it change direction when chasing prey.Birds also use their tails as a rudder to change direction during flight.
Geckos use tails as steering devices when they are falling off slippery surfaces. They rotate their tails as they fall and this ensures that they land on all four feet. Another way geckos use their tails for steering is during strong wind drafts where they direct them either left or right depending on where they want to go.
Tails for Courtship
Peacocks are best known for displaying a dazzling array of colors to their prospective mates. Scientists are still studying whether the female peafowl choose their mates based on the best display of plumage or whether they make the choice based on other factors. All the same, peacocks always displays their spectacular feathers when courting prospective mating partners.
Another bird, the Wilson’s Snipe, makes a clicking sound with its tail feathers during courtship. A recent scientific study at the Royal Tyrell Museum in Alberta, Canada found that some species of dinosaurs had developed quilled tail feathers for courtship in the same way as peacocks.
Tails for Communication
Tails can also be used by animals to communicate to one another. For example, the white-tailed deer flicks its tail to communicate to the rest of the flock of impending danger. Dogs wag their tails to send signals to each other and as a reaction to environmental cues. Squirrels will rapidly shake their large fluffy tails to indicate that they are upset or frightened. Giraffes also communicate using their tails as their vocal cord are underdeveloped.
Cats will give a variety of signals with their tails to indicate when they are scared, excited, relaxed, on heat, irritated or content. When a cat is showing submission or defeat, it will hold its tail low and tuck it between its hind legs.
Dogs Tail Wagging-- Poll
Tails for Defence
Crocodiles are known to use their tails to attack prey by sweeping them of their feet. They also use their tails to herd groups of fish towards the river bank so as to easily consume them. Thresher Sharks whose tails are shaped like scythes, use them to stun fish by applying a bullwhip strike in a single deadly blow. The video on the right shows how the Thresher Sharks attack prey using their tails. Sting rays inject a venomous sting using their tails. This serves as both a defensive and attack mechanism.
Other Reasons Why Animals Have Tails
The other reasons why animals have tails and what they use them for are:
- Many animals use tails as fly-whisks to keep irritating insects such as flies away. This is common in grazing animals such as cattle and buffaloes. In fact, the tails of such animals appear to have specifically evolved so as to whisk away insects.
- The Colugo Flying Lemur has a membrane that extends all the way to its tail. This membrane allows it to glide in the air over a considerable distance with the tail acting as a rudder to give it direction.
- Buffaloes have been reported to splash urine on their tails and use it to fend off intruders.
- Lizards can detach their tails as a way to escape from predators. The tails quickly grow back after they have been detached. This is an effective defense mechanism that ensures the lizard will survive an attack by its enemies who are left with just a piece of tail.