Editing Koala (section)

===Health and mortality===
Koalas live from 13 to 18 years in the wild although males may die sooner because of their more risky lives.<ref name="Martin-Handasyde"/>{{rp|69}} Koalas usually survive falls from trees, yet they can get hurt and even die, particularly inexperienced young and fighting males.<ref name="Martin-Handasyde"/>{{rp|72–73}} Around age six, the koala's chewing teeth begin to wear down and their chewing efficiency decreases. Eventually, the cusps disappear completely and the animal dies of starvation.<ref>{{cite journal | last1=Lanyon | first1=Janet M. | last2=Sanson | first2=G. D. | title=Koala (''Phascolarctos cinereus'') dentition and nutrition. II. Implications of tooth wear in nutrition | journal=Journal of Zoology | publisher=Wiley | volume=209 | issue=2 | year=1986 | issn=0952-8369 | doi=10.1111/j.1469-7998.1986.tb03573.x | pages=169–181| doi-access=free }}</ref> Koalas have few predators. [[Dingo]]s and large [[Pythonidae|pythons]] and some [[bird of prey|birds of prey]] may take them. Koalas are generally not subject to external parasites other than ticks around the coast. The mite ''[[Sarcoptes scabiei]]'' gives koalas [[mange]], while the bacterium ''[[Mycobacterium ulcerans]]'' skin ulcers, but these are uncommon. Internal parasites are few and have little effect.<ref name="Martin-Handasyde"/>{{rp|71–74}} These include the ''Bertiella obesa'' [[tapeworm]], commonly found in the intestine, and the ''[[Marsupostrongylus longilarvatus]]'' and ''[[Durikainema phascolarcti]] [[nematode]]s'', which are infrequently found in the lungs.<ref>{{cite journal |author1=Spratt, D. M. |author2=Gill, P. A. |title=''Durikainema phascolarcti'' n. sp. (Nematoda: Muspiceoidea: Robertdollfusidae) from the pulmonary arteries of the koala ''Phascolarctos cinereus'' with associated pathological changes |journal=Systematic Parasitology |year=1998 |volume=39 |pages=101–06 |doi=10.1023/A:1005957809179 |issue=2|s2cid=26037401|url=https://link.springer.com/content/pdf/10.1023/A:1005957809179.pdf }}</ref> In a three-year study of almost 600 koalas taken to the Australia Zoo Wildlife Hospital in Queensland, 73.8% of the animals were infected with parasitic [[protozoa]]l genus ''[[Trypanosoma]]'', the most frequent of which was ''[[Trypanosoma irwini|T.&nbsp;irwini]]''.<ref>{{cite journal | last1=McInnes| first1=L. M. | last2=Gillett| first2=A. | last3=Hanger| first3=J. | last4=Reid| first4=S. A. | last5=Ryan | first5=U. M. | title=The potential impact of native Australian trypanosome infections on the health of koalas (''Phascolarctos cinereus'') | journal=Parasitology | publisher=Cambridge University Press (CUP) | volume=138 | issue=7 | date=27 April 2011 | issn=0031-1820 | doi=10.1017/s0031182011000369|doi-access=free | pages=873–883| pmid=21524321 }}</ref>

Koalas can be subject to [[pathogen]]s such as ''[[Chlamydiaceae]]'' bacteria,<ref name="Martin-Handasyde"/>{{rp|74–75}} which can cause [[keratoconjunctivitis]], urinary tract infection, and reproductive tract infection.<ref name=jackson/>{{rp|229–30}} Such infections are common on the mainland, but absent in some island populations.<ref name="Martin-Handasyde"/>{{rp|114}} {{As of|2024}}, efforts are underway to use [[vaccination]] to try to stem the koala chlamydia epidemic.<ref>{{Cite web |last=Turnbull |first=Tiffanie |date=December 2024 |title=Chlamydia could kill off koalas. Can a vaccine save them in time? |url=https://www.bbc.com/news/articles/cjdnkdg1l8do |access-date=31 December 2024 |website=www.bbc.com |language=en-GB}}</ref> The [[koala retrovirus]] (KoRV) may cause [[koala immune deficiency syndrome]] (KIDS) which is similar to [[HIV/AIDS|AIDS]] in humans. Prevalence of KoRV in koala populations suggests it spread from north to south, for only southern populations have virus-free individuals.<ref>{{cite journal |author=Stoye, J. P. |title=Koala retrovirus: A genome invasion in real time |journal=Genome Biology |volume=7 |pages=241 |year=2006 |doi=10.1186/gb-2006-7-11-241 |pmid=17118218 |issue=11 |pmc=1794577 |doi-access=free }}</ref>

The animals are vulnerable to bushfires due to their slow speed and the [[Eucalyptus#Fire hazard|flammability of eucalypt trees]].<ref name="Martin-Handasyde"/>{{rp|26}} The koala instinctively seeks refuge in the higher branches where it is vulnerable to heat and fire. Bushfires divide the animal's habitat, which isolates them, decreases their numbers, and creates [[genetic bottleneck]]s.<ref name=moyal/>{{rp|209–11}} Dehydration and overheating can prove fatal.<ref name=jackson/>{{rp|80}} Consequently, the koala is vulnerable to the effects of climate change. Models of climate change predict warmer and drier climates, suggesting that the koala's range will shrink in the east and south to more [[mesic habitat]]s.<ref>{{cite journal |author1=Adams-Hosking, C. |author2=Grantham, H. S. |author3=Rhodes, J. R. |author4=McAlpine, C. |author5=Moss, P. T. |title=Modelling climate-change-induced shifts in the distribution of the koala |journal=Wildlife Research |year=2011 |volume=38 |issue=2 |pages=122–30 |doi=10.1071/WR10156}}</ref>