Koalas usually breed from August to February. Male koalas attract women through their loud vocal bellows. Women usually have a small koala every year, which produces about six generations of offspring in their lifetime, because females do not always breed every year. After immersion, the koala will give birth after more than one month (about 35 days) of pregnancy. Baby is called “joey” and is usually small. The baby may weigh less than .0025 pounds and be less than an inch in length, about the size of an almond. Joey was born blind and had no hair. It comes from the birth canal to the mother’s pouch, which lasted for about six to seven months of life. Even after growing to the mother’s pouch, Joey often stays with his mother until the second year’s brother or sister appears outside the mother’s pouch. Koala is primarily threatened by habitat loss. Human encroachment on its habitat from land clearing has a great impact on its survival. They may also be affected by bush fires and diseases. Koala is susceptible to bacteria that cause Chlamydia infection. This disease can lead to the development of conjunctivitis, an eye infection that can lead to blindness. Chlamydia can also cause pneumonia and infections in the urinary tract and reproductive system. In the koala population experiencing high environmental stress, the incidence of complications caused by chlamydia is increased.