The oldest wild koala recorded by Friends of the Koala was a female over 19 years old. Generally, their lifespan is 7 to 12 years. Koalas are aged by assessing the wear of their teeth.
Northern Rivers’ koalas are similar in appearance and size to Queensland koalas. They have a short, thick, grey and white coat and are smaller than their southern counterparts. A male koala’s average weight is 7- 8kg and a female is 6-7kg. That is a bit bigger than a basketball when they are curled up in a tree.
Across the region, koalas mate throughout the year, but the mating season peaks between November and January.
Koalas are the size of a small jelly bean when born; their eyes are shut, ears stuck to their head and they have no fur. They take a precarious journey from the cloaca, crawling into their mother’s pouch and attaching themselves to one of their mother’s two teats. Koala joeys spend the first 6 months of their lives in their mother’s pouch, and during this time grow fur and open their eyes. From 7-12 months they spend their time on their mum’s tummy, back or close by, learning how to navigate the treetops and adjusting to a diet of eucalyptus leaves. The next few months are spent in the same vicinity as their mother as they become weaned and fully independent. Females often stay in the same area as their mothers, but young males usually disperse.
The koala’s breeding cycle [344KB]
(source: Bill Phillips. Aust Govt. Publishing Service. 1990.)
Koalas survive mainly on a diet of eucalyptus leaves but they do not eat all species of eucalyptus. Their preferred trees in the Northern Rivers are Forest Red Gum, Tallowwood and Swamp Mahogany although they eat many other eucalypts as well. The trees koalas prefer to eat and use for shelter depend on the particular area and its surrounding habitat. For the Northern Rivers, non-eucalypts such as Paperbarks and She Oaks are often used. A koala’s metabolism is finely balanced between nutritional needs and energy requirements. Habitat disturbance upsets the balance because koalas must range further afield for their specific food requirements.
Why does a koala choose a particular tree in the forest to feed on? Awareness of the extreme fussiness of the koala in its choice of food dates from the time a koala was first taken into captivity in 1803. Failure of early attempts to exhibit koalas overseas where Eucalyptus foliage was not available and the mortality of many koalas in zoos even in Australia in the early 1900’s reinforced this view. Observations of feeding patterns of koalas in captivity showed that their diet changed at certain times of the year when animals rejected certain species of eucalypt that they showed a strong preference for in other seasons. These same habits have also been observed in the wild.
Field studies seem to indicate that koalas’ tree preference is influenced by their social organization, the structure of the tree and the chemistry of the leaves. Observed differences in tree species preference between sexes, and the preference for individual trees within species, may have their basis in the social organization of the koala. Although adult koalas are rarely seen in the same tree and appear to avoid one another, they nevertheless form clusters in which the home range of the dominant male and several females overlap extensively. Frequent use of a small number of trees by these koalas may provide a means of communication thus maintaining the cohesion of the cluster. Another theory is that the frequent cropping of the tree results in many new shoots being produced, which in turn attracts koalas.
The only structural features of trees that seem to attract koalas according to scientists are tree girth and height. Obviously the bigger the tree, the more food available and therefore the need to move between trees is reduced. This then reduces the energy expended by the koala and also reduces the chance of predation.
The preference for a narrow range of species within the huge Eucalyptus genus appears to have its basis in the chemistry of the leaves. Attempts to identify this basis have focused on either the nutritional or the toxic qualities of the foliage, and for various reasons no real basis has been identified.
Some clues as to why they choose one tree over another may be gleaned by studying the animals in their natural environment. Koalas first sample leaves while riding on their mothers’ backs and so become familiar with the foliage of the trees used by their mothers, but whether this influences their later choice of species has not yet been determined. Koalas frequently draw a branch of leaves to the vicinity of the nose before rejecting or accepting foliage. This will occur in a tree of a preferred species as well as when they are confronted by foliage from different species in captivity. This behaviour suggests that preferred browse food is identified by smell, however what they are actually smelling still remains a mystery.
Eucalypt foliage is considered a poor source of nutrients. It has been estimated that the entire amount of food eaten by a koala in a day (between 500grams and 1 kilogram of eucalypt leaf) contains about the same energy as a bowl of Cornflakes! No wonder the animals sit in the tree seemingly sleeping all day – they don’t have any energy to do anything else. The Eucalypt species favoured by koalas are those often found on fertile soils suggesting that nutrient quality may be an ultimate factor in species preference. The preferred species also tend to be associated with drainage lines or shallow water tables – an important factor in times of drought and at other times encouraging the growth of new tips which have been shown to be richer in nutrients than older leaves.
All in all, mystery still surrounds the whole issue.
For further information, please contact Mark Wilson (Nursery Manager) at firstname.lastname@example.org or phone 0413 339 554.
Koalas are known to live in an area by:
- scratch marks on tree trunks
- scats on the ground
- calls or sounds – video of a male koala grunting
- watch out for all the signs of koala activity and report sightings to us so accurate records of activity and sightings can be maintained.
Male koalas are generally larger than females and their testicles are sometimes visible. They have a longer, broader face and as adults are more muscular. At sexual maturity (2 -3 years) they develop a scent gland on their chest which looks like a dirty, vertical mark down the middle of their upper chest. They use this scent glad to claim their territory by rubbing it against the trunks of their trees.
Females are generally smaller, with fluffier ears. They have a rounder, softer face and are smaller in size.
Having said that, some females have broad faces and some males have lovely fluffy ears. There are always exceptions to the rule with koalas.
Koalas are widely distributed across the Northern Rivers of New South Wales although their numbers vary depending on available habitat. There are regular sightings in all the local government areas of Ballina, Byron, Kyogle, Lismore, Richmond Valley and Tweed. Koalas are found in areas with extensive bushland however they also survive in urban areas although they are much more vulnerable there to threats such as vehicles, dogs and swimming pools.
Koalas are known to use people’s yards and even the streets of some towns and villages. Sightings occur in Byron Bay, Kyogle, Clunes, Dunoon, Federal, Pottsville, Goonellabah and Wyrallah, to name a few. In most parts of urban Lismore koalas are commonplace, however there are concerns that koala numbers have decreased in recent times as habitat has been greatly reduced and that which remains is fragmented.
Koalas are extremely cute to look at and watch, but nevertheless are wild animals with very sharp teeth and long, sharp claws. They’re a very specialised animal to both care for and rescue. Because of this there are licensing controls and legal requirements concerning their care. Visit the NSW National Parks and Wildlife website to find out more about wildlife licensing in New South Wales.
Click on the following documents to learn more about koalas in the Northern Rivers:
- Northern Rivers Koala Facts [4MB]
- Koalas are important to Lismore [710KB]
- Koalas in our backyard [893KB]
What research is available on Koalas?
NSW North Coast Koala Study
A research team drawn from the University of Queensland, Southern Cross University and the University of Sydney is conducting the “NSW North Coast Koala” study which is focussed on the Lismore, Ballina, Byron and Tweed local government areas. The study is identifying where koalas are located and aims to better understand community attitudes and opinions towards koalas and their management.
The study website and community survey are now ready to go. The survey has two parts. The first involves dragging small icons onto a map of the NSW North Coast Region to mark where you have seen koalas, where you would like to see koalas in the future, and your preferences for future land use that may affect koala conservation. The second part is a simple questionnaire. As a thank you for participating you can choose to enter a prize draw.
This social science component is the project’s most innovative aspect as it will link community attitudes and willingness to engage in conservation activities with ecological understanding in a spatially explicit way, determining perhaps where and how conservation activities can be most effectively undertaken. This in turn will have broader significance for enhancing koala conservation programs elsewhere and for programs for other species of concern.
Local studies on Koalas in the Northern Rivers of NSW
- Skyline Road Monitoring Report 2018 [18MB] – Study aimed to assess the effectiveness of 2.5 kilometres of road exclusion infrastructure installed along Skyline Road Lismore to reduce koala road-kill and monitor the frequency of road underpass use.
- Koala Radio Tracking Study in the Lismore–Goonellabah Area 2007-2009 [937KB]
- Tweed Coast Habitat Study 2011 [1.7MB]
- Koala Southern Cross University Transect Study 2011 [7.5MB]
- Targeted field testing of wildlife road-crossing structures: koalas and canopy rope-bridges [1.2MB]
- Pilot study of site occupancy and detection probability of the koala (Lismore LGA, NSW) [1.3MB]
- Brown G et al Assessing the validity of crowdsourced wildlife observations for
- Quigley et al – J Virology 2018Olagoke_et_al-2018-npj_Vaccines
- Johnson et al – Nature genetics 2018
- Garofano 2018 – Field work synopsis – Koala Project
Other koala research
- Causes and prognoses of different types of fractures in wild koalas [1.2MB]
- Development of a lightweight, portable trap for capturing free-ranging Koalas [407KB]
- Interpreting patterns of population change in koalas from long-term datasets in Coffs Harbour, NSW [833KB]
- Conserving koalas: using DNA to look at the big picture – Australian Museum
- McAlpine et al. 2017 Influence of landscape change on Chlamydia in koalas. Landscape Ecology in press
- Decline causes of Koalas in SE Qld
- Conrad 2014 The Economic Value of the Koala
- Koalas and Tourism_An Economic Valuation_1997
- Cheng et al – Immunogenetics 2017
- McAlpine et al – LAND-D-15-00143_R2
- Speight et al – JWD 2016
- Spielman Genetic Considerations and the Release of Rehabilitated Australian wildlife
- Update on the progress towards developing a koala vaccine – January 2018
- Waugh et al – Biologicals 2016
- Waugh et al – JWD – KoRV 2016
- 2016 Williams and Narayan Koala BMC Zoology Review
- Narayan 2014 Stress response to environmental change
- Narayan Koala Abstract 2017
- Marshner, Higgins Krockenberger A Survey of Pesticide Accumulation in a Specialist Feeder,
Links to Koala Fact Sheets
Threats to Koalas
Downloadable file of Threats to Koalas [1.4MB].
Fragmentation/Loss of Habitat
Since European settlement, approximately 80% of koala habitat has been cleared. Of the remaining 20%, little is protected and most occurs on fragmented privately-owned land. Animals need to be able to move safely between different habitats through vegetation corridors and preferably by jumping from tree to tree. When forest is cleared for roads, houses and agriculture, koalas lose vital habitat and must face many dangers in order to find food, shelter and mates.
- Plant koala food trees to help connect habitats in your back yard, at school, along fences and waterways.
- Road crossings for animals
- Drive carefully and pay attention to road signage – slow down!
Predation by Dogs, Cats & Foxes
Hunting is normal behaviour for these animals and a koala’s best chance of surviving when in the vicinity of these predators is to keep them away from it.
- Keep cats inside or in a cage (especially at night from dusk to dawn).
- Preferably keep dogs in koala-proof runs or on leads in your yard
- Check trees around your house for koalas before leaving dogs unattended
- consider fox baiting programs
- for more information download our Responsible dog ownership information brochure [1.7MB]
Koalas are badly affected by a disease called Chlamydia. This is a small organism that is worst in koala populations under stress, for example when food is scarce, and causes several diseases in koalas:
- Conjunctivitis, which can cause blindness
- Urinary tract infections and reproductive tract infections that can cause female infertility
- If you see a Koala, look closely to see if it has sore eyes, a brown stained rump or is behaving unusually and if so, call our Rescue Hotline on 6622 1233.
- Plant koala food trees to help maintain healthy Koala populations.
Fences stop koalas from moving freely between habitats. They will climb most fences and can be caught on barbed wire or get into a yard with a dog and can’t get out.
- Educate the community on dangers of barbed wire and unfriendly fencing.
- Plant vegetation hedges instead of fences if you don’t have a dog.
- Avoid barbed wire fences, leave a gap at the bottom of the fence for Koalas to go underneath, or use friendly fences that have wooden posts or poles every 20m.
- Put lattices at the top of fences with occasional panels to the ground.
- Distribute a brochure on the issue and refer to wildlife friendly fencing website wildlifefriendlyfencing.com
Whenever a bushfilre occus the media focus is naturally on human life and property. However koalas, along with most other wildlife, are at great risk from bushfires. Bushfires destroy the understory and a hot fire will burn the canopy, leaving no food for Koalas, and a forest can take up to 10 years to recover from a major burn. In habitats surrounded by development, a single fire can wipe out an entire Koala population.
- Councils and National Parks need to ensure that hazard prevention burning occurs in stages i.e sections are burned each year not the whole area at once
- We all need to observe rules and stay out of National Parks and council reserves when they are closed due to ‘Total Fire Bans’
Questions about Volunteering?
Who can apply to be a volunteer?
In order to become a volunteer with Friends of the Koala you must:
- Be 18 years old or over
- Be a member of Friends of the Koala
- Undertake our volunteer training and agree to act in accordance with our Code of Conduct.
- Have your own email address as this is how we communicate with our volunteers
When can I volunteer?
Friends of the Koala provides volunteer opportunities throughout the year. All new volunteers are required to participate in a two-month probationary period. This gives you the best possible opportunity to immerse yourself in the experience, as well as gain valuable feedback from our experienced team members.
What skills and characteristics do I need?
There is no need for qualifications or industry specific experience. What we look for is motivation, confidence, a strong work ethic and a genuine desire to care for our koalas.
You should be in good health and be reasonably fit and prepared to take part to the best of your ability. We ask all prospective volunteers to declare any medical conditions, allergies, disabilities or existing injuries that may affect participation. This will be discussed with you in a confidential manner.
How much time do I have to commit?
The minimum commitment to volunteer is 4 weeks (volunteering 5 days a week) however this is generally offered to interstate and international travellers. Most of our volunteers’ volunteer on a regular basis, committing to 3-4 hours one day a week, depending on the role.
Will I receive training?
Some positions require volunteers to attend formal training prior to commencing in the role, while other roles may provide on-the-job training. Training is generally provided by Friends of the Koala.
What do I wear?
To ensure your safety while volunteering with Friends of the Koala, please wear a comfortable long sleeve shirt and trousers. We recommend you wear old work clothes. We also recommend strong safety work boots with protective toe caps. Covered shoes are essential.
Can volunteers pat and hold koalas?
The koalas we work with are wild koalas and therefore cannot be picked up, handled and treated like captive born koalas.
How do I become a volunteer?
Becoming a volunteer at Friends of the Koala begins with an expression of interest! Simply email [email protected], complete a membership application on our website or call our Office on (02) 6621 4664 to arrange an induction session.