The mating season for koalas is from December to March, which is summertime in Australia and the rest of the Southern Hemisphere.

During this time, male koalas compete with one another to attract mates. They bark, grunt, and even fight to get the attention of female koalas.

Males are usually quite docile but can fight during the mating season. Two males will often fight each other savagely to win the right to mate with a female.
Evidence of past conflicts can be seen in the scars that most adult males have on their faces, ears, and arms. The winner of the struggle gets the female.

The sounds tell other males to keep away, and also attract females. Each male judges the size and power of his rivals by the amount of noise they make. Often a young or small male hears the loud growls of a large male nearby, and keeps quiet.

A male koala makes a lot of noise so that females will notice him. He bellows loudly from the treetops so that nearby females will come closer to find out what all the racket is about. The call is so loud that it can be heard up to a half mile (0.8 km) away. A female koala makes a high pitched sound to call to her mate.

Females koalas usually mates every other year. She does not mate if she has a Joey that is less than a year old with her in her home range.

A male koala’s home range often overlaps with the home ranges of a few female koalas. If there are no females nearby, a male must travel on the ground to find one. The trip can be very risky.

They are more active at this time of year, and the males are noisier than usual. The koala’s breeding rate is fairly low. Females usually produce only one young each year, and twins are rare. Some females give birth only every two or three years, depending on their age and the quality of their habitat.

When a female koala reaches the age of 2 years, she is ready to mate. Males can mate when they are about 4 years old. As the breeding seasons arrives, and nearby males make their deep, roaring grunts, she replies with her own call to attract them. The male approaches, but he must wait until the female allows him to mate. If he tries too soon, she drives him away with bites and scratches. Most mating take place at night.

After mating, male and female koalas return to their own home ranges. The male does not help raise the baby. The mother feeds and protects it. With each new Joey, another life cycle begins.

A female koala may live 12 years and produce around six Joeys. She does not give birth every year, especially if there is a drought or a serious forest fire. There is no point in breeding if her young would have little chance of survival. Also, caring for a Joey makes her life slightly more dangerous. She must drink more than other koalas, because extra moisture is needed to produce milk. This brings the mother down from the trees, in search of pools and streams. On the ground, she is at greater risk from predators.

*On average, Koala females live longer than Koala males.

During the mating season, a male koala rubs his chest against the tree in which he lives. A gland on his chest produces smelly oil that tells other male koalas to stay away.


The Koalas have a life expectancy of about 15 years, can measure up to about 60 cm and the largest specimens weigh 12 kg.

Growing Up

A newborn koala, or Joey, is tiny and helpless. It weighs just one- hundredth of an ounce (0.5g) and is smaller than your thumb.

For the first few months the Joey stays inside its mother’s pouch, feeding on her milk. The pouch entrance remains closed.

By the age of 5 months, the Joey’s eyes are open and it can look out of the pouch. It still stays there and feeds on its mother’s milk.

About six months after Joey is born, its eyes open. It is now ready to see and explore the world outside. The Joey leaves its mother’s pouch for the first time for a short time, but it hangs onto its mother’s chest or back. It gradually moves farther, but it dashes back to the pouch if danger threatens it.

It is now about 8 in. (20 cm) long and weighs nearly 18 oz. (500 g) has eyes, ears, and fur. It crawls in and out of the pouch. It keeps very close to its mother and returns to the pouch within a few minutes gradually the outings become longer.
It begins to spend short periods of time outside the pouch. The Joey’s body is completely formed, but it is still growing. Now, instead of nursing inside the pouch, the Joey lies on its mother’s stomach to feed.

By this time the Joey begins to want more to eat than just milk.

By the seventh month, the Joey is ready to add something new to its diet. The mother begins to feed it eucalyptus leaves that she has chewed and begun to digest. This semi – liquid mush is pap.
So the mother gives her baby a food called pap, which is partly digested eucalyptus leaves that she has pre–chewed. The baby likes this new food. Pap gives the Joey a little taste of eucalyptus and prepares its stomach for digesting solid leaves.

By 8 months old, a Joey can pull itself out of the pouch. The Joey clings to its mother’s belly as she climbs through the trees. If it feels frightened or tired, it can always go back into the pouch. As it grows bigger and braver, the koala baby begins riding piggyback or on top of its mother’s head.

At 9 months old, the young koala is too big for its mother’s pouch and rides her back.

At 9 months old, the Joey weighs 2.2 lbs. (1kg). It is now too big for the pouch and rides on its mother’s back. Joey and mother keep in contact among the leaves by soft squeaks and hums. If the Joey wanders too far, the mother grunts angrily to summon it back.

The Joey is weaned at around 10 months, but stays near its mother for another two. By the time a year has passed, the mother may have mated again and have another Joey growing in her pouch.

By 12 months old, the Joey wants to eat only eucalyptus leaves. No more mothers’ milk and no more pap. The mother koala begins teaching her baby which eucalyptus leaves are good to eat.

When a Joey is about a year old, it gradually stops eating pap and drinking its mother’s milk. It starts to eat only eucalyptus leaves. As it grows bigger, the Joey learns to climb trees and find food on its own. It is almost an adult.

A one–year–old koala can live on its own, but it rarely does. Most young koalas stay with their mothers until they are two or three years old. A mother and her Joey are the only koalas that live together and share the same tree.

When it is three years old, the koala is an adult. It is now ready to have babies and start a new life cycle.

Koalas are not really fully grown until they turn 4 years old. Scientists say koalas in the wild usually live between 10 and 14 years.

Life in the Pouch a warm safe place

The tiny newborn koala lives and grows inside its mother’s pouch for the first six months of its life. The pouch is a warm, cozy place for the baby koala. It also keeps the Joey safe from predators.
The Joey (baby koala) grows very slowly inside the pouch. Its eyes open about 22 weeks after birth. For the first time, the Joey pokes its head through the pouch entrance and looks around. Even though the pouch opens upside down, the tiny koala can’t fall out. There are muscles around the pouch entrance, like the drawstring on a purse. The mother can tighten these to close the entrance and stop the baby from falling out. While her Joey is safe and snug in her pouch, the mother koala can continue life as normal.

The koala’s pouch is useful for living in trees. It holds a baby koala, so the mother can use both hands for climbing. The pouch also allows a mother to take her baby along while she looks for food.

The Joey uses the pouch as a safe place to rest when it is too tired to cling to its mother. The pouch hides a baby koala from animals that may want to eat it. It also keeps the Joey warm when the weather is cool.

The Upside-down pouch

Many female marsupials, such as kangaroos, have a pouch that opens on the upper side, like a pocket. But the koala’s pouch opens at the lower side. Its entrance is near the mother’s tail. Once the Joey is inside, the pouch entrance closes. The Joey is warm and protected, with plenty of milk to drink. Its mother can still move easily through the treetops.

The life cycle of koala

The Koala reaches sexual maturity at around 3 to 4 years, being that the females are more precocious.

The gestation time is about of 33 to 36 days. Koalas mate, or make babies, in the spring and summer. About 35 days after mating, a female gives birth to a tiny immature animal named Joey.
A Joey is only about 0.8 of an inch (2cm) long, it has no fur, and its eyes and ears are not formed. Baby koalas are born pink, bald, blind, and about the size of a jelly bean.

After emerging from the birth canal, the blind little creature clings to the fur on its mother’s stomach. As soon as it is born, the Joey knows by instinct that it must find its mother’s pouch. It must make its way across its mother’s belly to her pouch. If it fails to crawl inside the pouch, it will not survive. But the tiny baby almost always succeeds. A newborn koala must immediately crawl into its mother’s pouch. This journey is very difficult and usually takes 5 minutes. The first five minutes after birth may be the most important of its life.

The Joey cannot see or hear, and its back legs have not yet grown. It uses only its front legs to pull itself across its mother’s belly. They have an excellent sense of smell. This sense of direction helps it to climb to its mother’s pouch. It can smell milk in the pouch and find milk following the scent of the milk. As soon as the Joey crawls inside the pouch, the little Joey attaches itself to one of the mother two teats that provides it with nourishing milk.

It begins sucking on a nipple. The nipple swells inside the baby’s mouth so that the Joey cannot let go or fall off when its mother moves around. The milk it drinks give the Joey the nutrients, or nourishment, it needs to grow.

The Joey remains in the pouch for the first six to seven months of its life, feeding on its mother’s milk.

Bush fires

Some eucalyptus tree produce a gas that burns well, so forest fires in Australia can often travel quickly. Bush fires are one of the biggest killers of koalas, because the animals cannot move fast to avoid the approaching flames.

Moisture evaporates from the leaves of plants and later falls as rain. The more the land is cleared of trees and bushes, the less it rains, and the risks of drought and fire become greater.

Bushfires are now a major threat to koalas because much of their habitat is so broken up. Small, isolated koala populations can easily be wiped out by a single bushfire.

After the fire has died down, koalas’ paws can easily be burnt when they come to the ground to move to another tree. Because there is less ground cover after a fire, koalas are also more at risk from predators, such as dogs. Many often starve because their food supply can take several weeks to regrow.

The intense bushfires around Sydney in January 2002 occurred during a drought, and were one of the worst natural disasters to hit New South Wales for a century. These fires had a disastrous effect on koalas and other wildlife. Very few animals survived the fires, which lasted for around three weeks. Now that this area bush is reduced, it is more likely to be more seriously damage by large, intense fires in the future.

Tree dieback

Tree dieback causes trees to die rapidly, often in large numbers like these. Although it is becoming more common in rural areas, Dieback can be preventing by good farming techniques.

Disease threat to Koala Bears

Some koalas colonies have been harmed by the disease Chlamydia and other illnesses. Because of these threats, koalas are listed as vulnerable in two of the four Australian states that they inhabit. In one state, they are listed rare.

Diseases are natural part of life for koala. One common disease, Chlamydia, has been present in koala populations for many years. Scientists believe that it could act as a natural population control. This means that it is generally harmless in healthy koalas that have plenty of food and shelter, but it affects weaker animals or those that are under stress. Coping with loss of habitat and other difficulties can cause stress or upset in animals. Chlamydia is occurring more frequently in koalas today because they are under more stress. The disease causes various problems, including eye and lung infections. It causes some of the weaker animals to die, leaving the stronger ones to continue breeding.

Koalas Enemies

Most koalas are killed on the ground.

They are few the predators of the koala, the most important one is the Kennels dingo – a wild dog – that kills the old or sick koalas, since and an adult koala of good health is able to injure him seriously.
Their enemies include also foxes, dingoes, quolls (native cats), large snakes, domestic dogs, and occasionally even pet cats.

When frightened, a koala can run surprisingly fast for a short distance. If it makes it to a tree, the koala will jump from the ground onto the trunk. Pushing hard with its strong back legs, it soon disappears into the branches.

Adult dingoes like this one are about 20 inches (51 cm) High at the shoulder and 35 pounds (16 kg). That’s about the same size as Border collie. Dingoes eat everything from bugs and mice to rabbits and sheep.

Dingoes are Australia’s largest predators. They are powerful hunters that eagerly kill and eat any koala found walking on the ground.

A wild Australian dog called a dingo is one of koalas most feared predators on the ground.
But the dingo is not the only predator that koalas have to look out for when they are on the ground. Foxes, Pythons, and goannas, large Australian lizards. All prey on koalas and especially their young.

The red fox is not a native Australian animal, but was brought over from Europe by early settlers. Foxes are now thriving in the wild and are one of the major killers of koalas.

The green python can prey on koalas both on the ground and in the threes.

The monitor lizard’s chances to prey on a koala are limited to the ground.

Domestic dogs

In recent years, a common family pet – the domestic dog – has proved to be a major threat.
Thousands of koalas are killed each year by pet dogs. This is a particular problem in suburban areas where dogs are more common and trees are more scattered. Trees cover only a small percentage of suburban land.

For koalas to find enough to eat, their home ranges need to cover a large area. As a result they have to spend more time on the ground going from one food tree to the next, putting them more at risk to dog attacks.

Koalas come to the ground regularly to move between trees. They walk quite awkwardly but can run if they have to. They are particularly vulnerable to attack from predators when they are on the ground like this.

Dogs kill more koalas than any other animal. Yearly Deaths – Each year up to 4,000 koalas are killed by dogs and road traffic

But even in trees, young koalas are at risk from big birds of prey such as large owls and wedge-tailed eagles. They sometimes swoop down and snatch a young koala from its mother.

This barking owl hunts koalas at night.

This young bird is wedge – tailed eagle. Native to Australia, these birds are one of the world’s largest eagles. They prey includes rabbits, hares, snakes, lizards, and occasionally young koalas.

Koalas in danger

At one time, koalas were hunted for their thick fur, but now there are laws that protect them from hunters. Today, koalas face other dangers. One of the greatest threats to koalas is the destruction of their habitat or home. Many eucalyptus trees are cut down by people. Forests are cleared to make room for shopping malls, houses, and roads. Some trees are killed by diseases. Others are burnt in fires. When the eucalyptus trees disappear, the koalas that lived in them are left without a place to live.

Why are koalas threatened?

Today the number of koalas thought much of Australia is falling.

They are already becoming extinct in some places. The main threat is the loss of their habitat. They depend upon certain types of eucalyptus woodland to survive, but these are getting smaller and smaller in size. This is because humans have cleared away vast areas of bush for farming, houses, roads, and factories. The situation is made worse by bushfire and the gradual loss of trees, known as tree dieback, caused by harmful changes in the environment.

Koalas living in or near towns are also in danger from the domestic dogs that often attack and kill them. Many koalas are run over by cars.

The future for koalas

Eucalyptus woodlands are fast disappearing in Australia. Koalas depend on eucalyptus for their food and shelter.


Koalas are now overcrowded on Kangaroo Island.
Too many koalas living in too few trees mean less food for all the species that live in these woodlands.

Because there is no opportunity for koalas from other populations to reach the Island, the koalas there, are now suffering from inbreeding. The introduced koalas did not have the Chlamydia bacterium that acts as a natural population control, so their numbers have been increasing too fast. The latest koala survey in 2001 estimated that there were between 21,000 and 33,000 koalas on the island (although not all scientists agree that the numbers are so high). What is known for sure is that the koalas on Kangaroo Island are now very overcrowded. There are too few trees where young koalas can set up their own home ranges, and they are steadily munching their way through a limited supply of eucalyptus leaves, destroying the habitat of other threatened species. This situation is an example of how intervention by humans can upset the balance of nature.

Artificial birth control is one method that has been used to reduce the number of koalas on the island. So far almost 3,500 animals on the island have been sterilized (so they can no longer breed) and released back into the wild. Around 1,200 of these have now been relocated to the mainland. However, not all scientists agree with this solution

Koala history

Koalas also played an important role in the stories and legends that aborigines told about the natural world.

Like the bison in North America, the koala was both a source of food and an animal respected for its supernatural power.

Aboriginal people were the first human to live in Australia and probably arrived around 60,000 years ago. Although some tribes killed koalas for food, it is thought that these animals were still very common when the first European arrived in Australia in 1788.

In the 1800s large numbers of people came from Europe to settle in Australia. They began to cut down the native forest to make way for their farmland and human neighborhoods. As well as destroying the koalas’ habitat, the settlers started to kill them for their fur.

The fur trade had a devastating effect on koala populations. In the 1800s and early 1900s millions of koalas were killed. Most skins were exported to Europe and United States. This large-scale slaughter of koalas caused a major public outcry. By the end of 1930s, koalas were declared a protected species and deliberate killing of koalas become extinct in the state of South Australia. Their numbers were massively reduced in other places. Although the koala was finally given some protection, laws were not brought in at that time to protect the eucalyptus trees that the koalas need for food and shelter

The ancestors of today’s koalas probably lived in the rain forests that once covered much of Australia.
Scientists have found fossil remains of koala – like animals that are around 25 million years old. Over time Australia’s climate gradually became drier. Eucalyptus trees began to grow and koalas evolved to live alongside them.

European settlers also cleared vast areas of eucalyptus woodland to plant crops and graze farm animals. Four – fifths of the original eucalyptus woods disappeared. The koala rapidly became a rare species.

Between 1919 and 1924, it is estimated that eight million koalas were killed. In 1927 the Australian Government decided to do something to save the koala from extinction. It passed a law making it illegal to hunt and kill koalas.

And forbidding the export of koala furs. But many people still hunted them for food.

But the koala is still not safe. While it is against the law to kill a koala, its habits are still not protected from destruction. Farmers have chopped down forests of eucalyptus trees to make room for their crops. Logging companies have done the same to turn the trees into lumber. Builders have destroyed koala habitat to create space for new houses and businesses.

Even where people have left the koalas’ habitat untouched, they are in danger. By breaking up their larger habitat, humans have isolated these animals. They often live in pockets or clumps of trees separated from other koalas. To reach a new group of trees, many koalas have had to cross newly built roads, crowded with traffic. Many have been struck and killed by speeding autos trying to cross roads to reach new trees. Experts believe that about four thousand kolas are killed by cars and dogs each year.

About 100,000 wild koalas are left in Australia.

The endangered species list is an official list of the world’s animals that are in danger of dying out.
Koalas have been on this list in the past. Today, instead of being listed as “endangered “Koalas are listed as “threatened.” This means their numbers have increased.

Australia creates contraceptive for koalas

Koalas are victims of an increase in their own population.

Around 3 thousand females in a colony of koala bears will be treated with contraceptives in Australia.
Forest rangers in Victoria’s State, in the south of the country, fear that the koalas of the region can go hungry if the growth of the population is not contained.

There are around 10 thousand koalas in the National Park in Mount Eccles, in the western region of Victoria.

It is a considerable increase in the population of the species at these localities, since 25 years ago have been brought to the region 77 koalas.

Because of its proliferation, the koalas eat 70% of their favorite food.


The forest rangers believe that if drastic action is not taken, the trees can gradually become extinct and the population of koala may die of hunger.

In the past, attempts to promote the sterilization of koalas did not work.

In the new contract, forest guards intend to capture 3 thousand females and introduce a small tube under their skin which will release the same hormone contained in contraceptive pills.

The project brings some risks. The Australian Foundation of Koalas says that the animals will be able to develop tumors and affirms that the measure is cruel and unnecessary.

But the method has been used successfully to contain the growth of populations of kangaroos, monkeys and wild cats.