Breeding Behaviors of the Female Koalas

Among marsupials, the female koalas exhibit a very interesting and unique breeding behavior. Even within koalas, the breeding behavior of the female koalas is also significantly different than that of the male koalas. The way by which the female koalas attract the male koalas and when they struggle or shy away from them are one of the hallmark breeding behaviors of the female koalas (discussed in detail below).

Female koalas exhibit a very unique and interesting breeding behavior. The female koalas are capable of breeding from 18th the age of 18 months and onwards.

As compared to the male koalas, the female koalas are capable of breeding from the 2nd year (18 months to be precise). On the other hand; the male koalas usually start breeding at their peak or prime age which is the 4th year of their life. The koala researchers have identified various breeding and mating behaviors of the female koalas which will be highlighted throughout this article.

Female Koalas
Unique Breeding Behavior Male vs. Female Koalas
Different Breeding Behavior Breeding Age of Female Koalas
18 months and Onwards Breeding Age of Male Koalas
4 Years and Onwards

The breeding season of koalas starts in September (Australian spring season) and it lasts till the end of April (Australian summer season). This breeding season is specifically true for the female koalas, as they only come into heat (estrous) during this breeding season. The female koalas are also termed as seasonally polyestrous because they tend to exhibit continuous estrous cycles during the breeding season only.

The breeding season of the female koalas starts in September and lasts till the end of April. The female koalas are seasonally polyestrous. Male koalas on the other hand are capable of breeding throughout the year.

On the other hand; the male koalas are capable of breeding almost any time of the year. It has also been observed that the breeding and mating season for the northern female koalas (such as the koalas of Queensland) starts early while the breeding and mating season for the Southern koalas (Victorian region and South Australian region koalas) starts a bit late.

Koalas' Breeding Season
September to April Females Estrous Cycles
Only Active in Breeding Season Female Koalas have
Polyestrous cycles Male Koalas are
Capable of Breeding any time Northern Koalas'
Breeding Season starts Early Southern Koalas'
Breeding Season starts Late

During the breeding season, the female koalas respond to the high-pitched bellowing of the male koalas by lower snarl or mild bellowing sound. This is the key indicator for the male that the female is in estrus and it is the right time to mate. As soon as the male koala approaches the female koala for mating, the lower snarling or bellowing sound of the female koala gets a bit louder while at the final approach the female tends to struggle away from the male koala.

The female koalas greet and respond the male koalas by making lower snarls or low-pitched bellowing. Upon approaching; the female koala tends to struggle away from the male koala and she either bites or screams.

Onwards; the male koala grasps the female koala from neck or head while the female koala either bites back or scream during their mating process. The overall act of the mating between the male and female koalas lasts for a minute or two. The male koala usually leaves after mating but may occasionally wait for another attempt after some hours by staying near the tree of the female koala.

Male Koalas in Breeding Season
Create Loud Vocalizations Female Koalas in Breeding Season
Respond to Male's Vocalization Female Koalas during Mating
Struggles Away from Male Koala Koalas' Sexual Intercourse
Lasts for a Minute or Two Male Koalas Breeding Attempts
Usually Once Sometimes Twice

The female koalas are usually capable of breeding every second year with the male koalas. However; if the living conditions are appropriate and the availability of the food such as the Eucalyptus foliage are in abundance then the female koalas can mate every year as well. On the other hand; in case of the droughts, the female koalas may delay breeding even beyond the normal 2nd year interval.

Usually; the female koalas can breed every second year of their life with the male koalas. However; they can breed every year too but it depends upon favorable living conditions i.e., continuous food supply.

As mentioned earlier, the female koalas start breeding from the age of 18 months which means that they can breed even when they are not fully mature yet. The female koalas can continue to successfully breed at the age of 14 years. However; females more than 16 years of age have also been witnessed to successfully breed with the male koalas as well.

Breeding Capability
Female Koalas can Breed every 2nd Year Breeding Age of Female Koalas
18 months to 14 years Breeding Age of Male Koalas
4 Years and Onwards Male Koalas can also Breed
From 18 months and Onwards

The female koalas who are not having an estrous cycle tend to remain very aggressive towards the male koalas. Mostly; such female koalas might be raising a young joey inside their pouch. Such females are also called the lactating females. The koala joeys (more than 8 months old) are often at risk of dying, if the male koala approaches the female koalas for mating. The bigger joeys fail to fit inside the protection of their mother’s pouch and they must cling on the back of their mother in such a situation.

The female koalas who are not having their estrus cycle during the breeding season tend to be very aggressive against the male koalas. Such female koalas are usually the lactating females feeding their young joeys.

Therefore; the risk of falling or getting mauled by the male koala becomes a real possibility. However; the female koalas aggressively defend their joeys in such a situation at any cost. It has also been observed that the female koalas tend to remain within their territories while the male koalas are the one that approach them. This is the key reason that during the breeding season you may find a lot of wandering male koalas as compared to the non-breeding season.

Females Without Estrous Cycles
Very Aggressive Lactating Female Koalas
Protective & Aggressive Koala Joeys are at Risk
When Male Koalas Approach Female Koalas for Mating

Lastly; during the breeding season, the female koalas are also known to involve in the same-sex sexual behavior or homosexual behavior too. In such a situation a female koala may perform almost the same act of breeding or mating as of the male koalas. The female koalas who are usually in estrus tend to mount over the other female koalas for mating. This kind of behavior has specifically been witnessed within the captive female koalas.

Female koalas are also known to perform the same-sex sexual behavior by mounting on the backs of other female koalas.

However; such a breeding behavior is yet to be witnessed within the wild but the observers believe that it will be common within the wild female koalas as well. Some observers believe that it might have something to do with the race of dominance or competition within the female koalas during the mating season. On the other hand; homosexuality or the same-sex sexual behavior has never been observed within the male koalas. Rather they are very aggressive towards one another.

Female Koalas also Exhibit
Homosexual Behavior Female Koalas Tend to
Mount on the back of Female Koalas Homosexual Female Koala Behavior
Is an Act of Dominance & Competition