Document ID: chunk:federal_register_of_legislation:F2022L00555:body:0:p77
Version: federal_register_of_legislation:F2022L00555
Segment Type: other
Provision Reference: 
Character Range: 238999–241918

southern range being about twice as heavy as those from northern Australia (average of 12 kg in Victoria cf. 6.5 kg in Queensland) (Martin and Handasyde 1999). Northern Koalas also tend to have shorter, silver-grey fur, whereas those in their southern range have longer, thicker, brown-grey fur (Martin and Handasyde 1999).
Previously, three subspecies (P. c. adustus, P. c. cinereus and P. c. victor) were described based on this clinal body size and colour variation (Troughton 1957); however, there is no genetic support for this (Houlden et al. 1999; Kjelsen et al. 2016; Neaves et al. 2016) and the Koala is now considered a single species.

27.  Behavioural ecology and demography
The Koala is a semi-arboreal species spending most of its time in the tree branches of eucalypt forests; however, unlike other arboreal species such as gliders, it mainly uses the ground, rather than the canopy, to travel between trees (Marsh et al. 2014). It is largely sedentary, solitary and primarily nocturnal, with adults having limited social interactions (Martin and Handasyde 1999), although individuals have extensive overlap in home territories (Ellis et al. 2009; Mitchell 1990).

Mother and joey, Magnetic Island, Qld. Image: © E. Vanderduys, CSIRO.

27.1 Reproduction
Koala development follows a pattern of sexual bi-maturism with females obtaining reproductive age between two and three years of age, and males at four years (Martin and Handasyde 1999: McLean and Handasyde 2007). Mature females generally produce one offspring a year with births occurring between October and May (Close et al. 2017; McLean 2003; Thompson 2006) following a 35-day gestation period (Martin and Handasyde 1999; Tyndale-Biscoe and Renfree 1987). Koala reproduction is influenced by seasonality, and the timing of the breeding season can differ between northern and southern populations (Ellis et al. 2010b). Local factors, including population density, food quality and availability and climate influence the timing of breeding (McLean and Handasyde 2007; Ballantyne et al. 2015). Koalas may not breed every year if conditions are unfavourable, and breeding can be unsuccessful due to poor body condition or disease (e.g. Chlamydia) (McLean and Handasyde 2007).
Southern populations have shown seasonal sex biases in offspring (McLean and Handasyde 2007), although this has not been found in Queensland (Ellis et al. 2010b). The newborn joey suckles from inside the pouch for around nine months (240–270 days) and is then carried on the mother's back for an estimated three months, until it is weaned at around 12 months (Ellis et al. 2010b; Martin and Lee 1984). Weaning coincides with periods of high food availability and favourable climatic conditions. This ensures the best survival conditions for offspring approaching independence (Ballantyne et al. 2015). The joey remains near the mother for another year before reaching sexual