Editing Emu (section)

== Behaviour and ecology ==
Emus are [[Diurnality|diurnal]] birds and spend their day foraging, preening their plumage with their beak, dust bathing and resting. They are generally gregarious birds apart from the breeding season, and while some forage, others remain vigilant to their mutual benefit.<ref name=Ekesbo>{{cite book|author=Ekesbo, Ingvar |title=Farm Animal Behaviour: Characteristics for Assessment of Health and Welfare |url=https://books.google.com/books?id=vFX8fJp6pmoC&pg=PA182 |year=2011 |publisher=CABI |isbn=978-1-84593-770-6 |pages=174–190}}</ref> They are able to swim when necessary, although they rarely do so unless the area is flooded or they need to cross a river.<ref name=e9 />

[[File:Emus bathing Feb09.jpg|thumb|Emus bathing on a very hot summer day in a shallow pond]]

Emus begin to settle down at sunset and sleep during the night. They do not sleep continuously but rouse themselves several times during the night. When falling asleep, emus first squat on their [[Tarsus (skeleton)|tarsi]] and enter a drowsy state during which they are alert enough to react to stimuli and quickly return to a fully awakened state if disturbed. As they fall into deeper sleep, their neck droops closer to the body and the eyelids begin to close.<ref name=im /> If there are no disturbances, they fall into a deeper sleep after about twenty minutes. During this phase, the body is gradually lowered until it is touching the ground with the legs folded underneath. The beak is turned down so that the whole neck becomes S-shaped and folded onto itself. The feathers direct any rain downwards onto the ground. It has been suggested that the sleeping position is a type of camouflage, mimicking a small mound.<ref name=im>{{cite journal |doi=10.1071/MU960193 |journal=Emu |issue=3 |year=1960 |volume=60 |pages=193–195 |title=The sleep of the emu |author=Immelmann, K.|bibcode=1960EmuAO..60..193I }}</ref> Emus typically awake from deep sleep once every ninety minutes or so and stand upright to feed briefly or defecate. This period of wakefulness lasts for ten to twenty minutes, after which they return to slumber.<ref name=im /> Overall, an emu sleeps for around seven hours in each twenty-four-hour period. Young emus usually sleep with their neck flat and stretched forward along the ground surface.<ref name=im />

[[File:Emu vocalization.ogv|thumb|thumbtime=00:02|right|Emu grunting and hissing; note the inflating throat]]
[[File:Emus. Western NSW, 1976.jpg|thumb|400px|Emus. Western NSW, 1976]]

The vocalisations of emus mostly consist of various booming and grunting sounds. The booming is created by the inflatable throat pouch; the pitch can be regulated by the bird and depends on the size of the aperture.<ref name="AM" /><ref name="S. Davies" /><ref name=e6 /> Most of the booming is done by females; it is part of the courtship ritual, is used to announce the holding of territory and is issued as a threat to rivals. A high-intensity boom is audible {{convert|2|km|mi}} away, while a low, more resonant call, produced during the breeding season, may at first attract mates and peaks while the male is incubating the eggs.<ref name=HBWA/> Most of the grunting is done by males. It is used principally during the breeding season in territorial defence, as a threat to other males, during courtship and while the female is laying. Both sexes sometimes boom or grunt during threat displays or on encountering strange objects.<ref name=HBWA/>

On very hot days, emus pant to [[Thermoregulation|maintain their body temperature]]. Their lungs work as [[evaporation|evaporative]] coolers and, unlike some other species, the resulting low levels of [[carbon dioxide]] in the blood do not appear to cause [[alkalosis]].<ref>{{cite journal|doi=10.1007/BF00714584|author1=Maloney, S.K. |author2=Dawson, T.J. |year=1994 |title= Thermoregulation in a large bird, the emu (''Dromaius novaehollandiae'') |journal=Comparative Biochemistry and Physiology B |volume=164 |pages=464–472 |issue=6 |s2cid=44697212 }}</ref> For normal breathing in cooler weather, they have large, multifolded nasal passages. Cool air warms as it passes through into the lungs, extracting heat from the nasal region. On exhalation, the emu's cold nasal [[nasal concha|turbinates]] condense moisture back out of the air and absorb it for reuse.<ref>{{cite journal |author1=Maloney, S.K. |author2=Dawson, T.J. |year=1998 |title=Ventilatory accommodation of oxygen demand and respiratory water loss in a large bird, the emu (''Dromaius novaehollandiae''), and a re-examination of ventilatory allometry for birds |journal=Physiological Zoology |volume=71 |issue=6 |pages=712–719 |pmid=9798259|doi=10.1086/515997 |s2cid=39880287 }}</ref> As with other ratites, the emu has great [[Homeothermy|homeothermic]] ability, and can maintain this status from {{convert|−5|to|45|°C}}.<ref name=Maloney2008>{{cite journal |doi=10.1071/EA08142 |journal=Australian Journal of Experimental Agriculture |year= 2008 |volume=48 |pages= 1293–1301 |title=Thermoregulation in ratites: a review |author= Maloney, Shane K.|issue=10}}</ref> The [[Thermal neutral zone|thermoneutral zone]] of emus lies between {{convert|10|and|30|°C}}.<ref name=Maloney2008/>
[[File:Emu at zoo.jpg|thumb|An emu sitting on the ground at a zoo.]]
As with other ratites, emus have a relatively low [[basal metabolic rate]] compared to other types of birds. At {{convert|−5|°C}}, the metabolic rate of an emu sitting down is about 60% of that when standing, partly because the lack of feathers under the stomach leads to a higher rate of heat loss when standing from the exposed underbelly.<ref name=Maloney2008/>

=== Diet ===
[[File:Emu feeding on grass.ogg|thumb|thumbtime=00:43|An emu foraging in grass]]

Emus forage in a [[diurnality|diurnal]] pattern and eat a variety of native and introduced plant species. The diet depends on seasonal availability with such plants as ''[[Acacia]]'', ''[[Casuarina]]'' and [[Poaceae|grasses]] being favoured.<ref name=HBWA>{{cite book |title=Handbook of the Birds of the World Alive |last=Bruce |first=M.D. |year=1999 |editor-last=del Hoyo |editor-first=J. |editor2-last=Elliott |editor2-first=A. |editor3-last=Sargatal |editor3-first=J. |chapter=Common emu (''Dromaius novaehollandiae'') |publisher=Lynx Edicions |isbn=978-84-87334-25-2 |chapter-url=http://www.hbw.com/species/common-emu-dromaius-novaehollandiae |url-access=registration |url=https://archive.org/details/handbookofbirdso0001unse }}{{subscription required}}</ref> They also eat insects and other arthropods, including grasshoppers and [[Cricket (insect)|crickets]], [[beetle]]s, [[cockroach]]es, [[Coccinellidae|ladybirds]], [[Bogong moth|bogong]] and [[Heliothis|cotton-boll]] moth larvae, ants, [[spider]]s and [[millipede]]s.<ref name=HBWA/><ref>{{cite book |author1=Barker, R.D. |author2=Vertjens, W.J.M. |year=1989 |title=The Food of Australian Birds: 1 Non-Passerines |publisher= CSIRO Australia |isbn=978-0-643-05007-5}}</ref> This provides a large part of their protein requirements.<ref name=e44 /> In Western Australia, food preferences have been observed in travelling emus; they eat seeds from ''[[Acacia aneura]]'' until the rains arrive, after which they move on to fresh grass shoots and caterpillars; in winter they feed on the leaves and pods of ''[[Cassia (genus)|Cassia]]'' and in spring, they consume [[grasshopper]]s and the fruit of ''[[Santalum acuminatum]]'', a sort of quandong.<ref name="S. Davies" /><ref name="Powell">{{cite book|title=Leaf and branch: Trees and tall shrubs of Perth |author=Powell, Robert |publisher= Department of Conservation and Land Management |year=1990 |page=197 |isbn=978-0-7309-3916-0}}</ref> They are also known to feed on wheat,<ref name=e31>Eastman, p. 31.</ref> and any fruit or other crops that they can access, easily climbing over high fences if necessary.<ref name=e44 /> Emus serve as an important agent for the dispersal of large viable seeds, which contributes to floral biodiversity.<ref name="Powell" /><ref>{{cite journal|doi=10.1071/MU99030|author1=McGrath, R.J. |author2=Bass, D. |year=1999 |title=Seed dispersal by emus on the New South Wales north-east coast |journal=[[Emu (journal)|Emu]] |volume=99 |pages=248–252|issue=4|bibcode=1999EmuAO..99..248M }}</ref> One undesirable effect of this occurred in Queensland in the early twentieth century when emus fed on the fruit of [[Opuntia|prickly pears]] in the outback. They defecated the seeds in various places as they moved around, and this led to a series of campaigns to hunt emus and prevent the seeds of the invasive cactus being spread.<ref name=e44>Eastman, p. 44.</ref> The cacti were eventually controlled by an introduced moth (''[[Cactoblastis cactorum]]'') whose larvae fed on the plant, one of the earliest examples of [[Biological pest control|biological control]].<ref>{{cite web |url=https://www.daf.qld.gov.au/__data/assets/pdf_file/0014/55301/IPA-Prickly-Pear-Story-PP62.pdf |title=The prickly pear story |year=2015 |publisher=Department of Employment, Economic Development and Innovation, State of Queensland |access-date=21 July 2015}}</ref> The [[δ13C|δ{{sup|13}}C]] of the emu's diet is reflected in the δ{{sup|13}}C of the [[calcite]] of its egg shell.<ref name="Lynch-et-al-2007">{{cite journal | last1=Lynch | first1=Amanda H. | last2=Beringer | first2=Jason | last3=Kershaw | first3=Peter | last4=Marshall | first4=Andrew | last5=Mooney | first5=Scott | last6=Tapper | first6=Nigel | last7=Turney | first7=Chris | last8=Van Der Kaars | first8=Sander | title=Using the Paleorecord to Evaluate Climate and Fire Interactions in Australia | journal=[[Annual Review of Earth and Planetary Sciences]] | publisher=[[Annual Reviews (publisher)|Annual Reviews]] | volume=35 | issue=1 | year=2007 | issn=0084-6597 | doi=10.1146/annurev.earth.35.092006.145055 | pages=215–239| bibcode=2007AREPS..35..215L }}</ref>

[[Gastrolith|Small stones]] are swallowed to assist in the grinding up and digestion of the plant material. Individual stones may weigh {{convert|45|g|oz|abbr=on|1}} and the birds may have as much as {{convert|745|g|lb|abbr=on}} in their [[gizzard]]s at one time. They also eat charcoal, although the reason for this is unclear.<ref name="S. Davies" /> Captive emus have been known to eat shards of glass, marbles, car keys, jewellery and nuts and bolts.<ref name=e44 />

Emus drink infrequently but ingest large amounts when the opportunity arises. They typically drink once a day, first inspecting the water body and surrounding area in groups before kneeling down at the edge to drink. They prefer being on firm ground while drinking, rather than on rocks or mud, but if they sense danger, they often stand rather than kneel. If not disturbed, they may drink continuously for ten minutes. Due to the scarcity of water sources, emus are sometimes forced to go without water for several days. In the wild, they often share water holes with other animals such as kangaroos; they are wary and tend to wait for the other animals to leave before drinking.<ref name=e15>Eastman, p. 15.</ref>

=== Breeding ===
[[File:Emu Egg.JPG|thumb|alt=Emu egg|Dark green emu egg]]

Emus form breeding pairs during the summer months of December and January and may remain together for about five months. During this time, they stay in an area a few kilometres in diameter and it is believed they find and defend territory within this area. Both males and females put on weight during the breeding season, with the female becoming slightly heavier at between {{convert|45|and|58|kg|lb|abbr=on}}. Mating usually takes place between April and June; the exact timing is determined by the climate as the birds nest during the coolest part of the year.<ref name=e23 /> During the breeding season, males experience hormonal changes, including an increase in [[luteinizing hormone|luteinising hormone]] and [[testosterone]] levels, and their [[testicle]]s double in size.<ref>{{cite journal|doi=10.1016/S0378-4320(98)00110-9 |author1=Malecki, I.A. |author2=Martin, G.B. |author3=O'Malley, P.J. |author4=Meyer, G.T. |author5=Talbot, R.T. |author6=Sharp, P.J. |year=1998 |title=Endocrine and testicular changes in a short-day seasonally breeding bird, the emu (''Dromaius novaehollandiae''), in southwestern Australia |journal=Animal Reproduction Science |volume=53 |issue=1–4 |pages=143–155 |pmid=9835373 }}</ref>

Males construct a rough nest in a semi-sheltered hollow on the ground, using bark, grass, sticks and leaves to line it.<ref name=Davies /> The nest is almost always a flat surface rather than a segment of a sphere, although in cold conditions the nest is taller, up to {{convert|7|cm|abbr=on}} tall, and more spherical to provide some extra heat retention. When other material is lacking, the bird sometimes uses a [[Triodia (grass)|spinifex tussock]] a metre or so across, despite the prickly nature of the foliage.<ref name=e23 /> The nest can be placed on open ground or near a shrub or rock. The nest is usually placed in an area where the emu has a clear view of its surroundings and can detect approaching predators.<ref name=e24>Eastman, p. 24.</ref> The nest can contain eggs from multiple emus the number is usually between 15 and 25 eggs.<ref>{{Cite web |title=Emu |url=https://nationalzoo.si.edu/animals/emu |access-date=2024-03-21 |website=Smithsonian's National Zoo and Conservation Biology Institute |language=en}}</ref>

Female emus court the males; the female's plumage darkens slightly and the small patches of bare, featherless skin just below the eyes and near the beak turn turquoise-blue. The colour of the male's plumage remains unchanged, although the bare patches of skin also turn light blue.  When courting, females stride around, pulling their neck back while puffing out their feathers and emitting low, monosyllabic calls that have been compared to drum beats. This calling can occur when males are out of sight or more than {{convert|50|m|ft|-1}} away.  Once the male's attention has been gained, the female circles her prospective mate at a distance of {{convert|10|to|40|m|ft|-1}}. As she does this, she looks at him by turning her neck, while at the same time keeping her rump facing towards him. If the male shows interest in the parading female, he will move closer; the female continues the courtship by shuffling further away but continuing to circle him.<ref name=e23 /><ref name=Coddington/>

If a male is interested, he will stretch his neck and erect his feathers, then bend over and peck at the ground. He will circle around and sidle up to the female, swaying his body and neck from side to side, and rubbing his breast against his partner's rump. Often the female will reject his advances with aggression, but if amenable, she signals acceptance by squatting down and raising her rump.<ref name=Coddington/><ref name=Patodkar>{{cite journal |author1=Patodkar, V.R. |author2=Rahane, S.D. |author3=Shejal, M.A. |author4=Belhekar, D.R. |year=2011 |title=Behavior of emu bird (''Dromaius novaehollandiae'') |journal=Veterinary World |volume=2 |issue=11 |pages=439–440 |url=http://www.veterinaryworld.org/Vol.2/November/9.html }}</ref>

[[File:Emu Gelege.jpg|right|thumb|alt=Nest and eggs|Nest and eggs]]

Females are more aggressive than males during the courtship period, often fighting for access to mates, with fights among females accounting for more than half the aggressive interactions during this period.  If females court a male that already has a partner, the incumbent female will try to repel the competitor, usually by chasing and kicking.  These interactions can be prolonged, lasting up to five hours, especially when the male being fought over is single and neither female has the advantage of incumbency. In these cases, the females typically intensify their calls and displays.<ref name=Coddington/>

The sperm from a mating is stored by the female and can suffice to fertilise about six eggs.<ref name=Patodkar/> The pair mate every day or two, and every second or third day the female lays one of a clutch of five to fifteen very large, thick-shelled, green eggs. The shell is around {{convert|1|mm|in|2|abbr=on}} thick, but rather thinner in northern regions according to indigenous Australians.<ref name=Davies /><ref name=e24 /> The shell is substantially composed of [[calcite]], and its [[δ13C|δ{{sup|13}}C]] is a function of the emu's diet.<ref name="Lynch-et-al-2007" /> The eggs are on average {{convert|13|x|9|cm|in|abbr=on}} and weigh between {{convert|450|and|650|g|lb|1|abbr=on}}.<ref name=Campbell>{{cite book|author1=Campbell, Bruce |author2=Lack, Elizabeth |title=A Dictionary of Birds |url=https://books.google.com/books?id=kZqJAAAAQBAJ&pg=PA179 |year=2013 |publisher=Bloomsbury Publishing |isbn=978-1-4081-3839-7 |page=179}}</ref> The maternal investment in the egg is considerable, and the proportion of yolk to [[Egg white|albumen]], at about 50%, is greater than would be predicted for a precocial egg of this size. This probably relates to the long [[Egg incubation#Avian incubation|incubation]] period which means the developing chick must consume greater resources before hatching.<ref>{{cite journal |author=Dzialowski, Edward M. |author2=Sotherland, Paul R. |year=2004 |title=Maternal effects of egg size on emu ''Dromaius novaehollandiae'' egg composition and hatchling phenotype |journal=Journal of Experimental Biology |volume=207 |issue=4 |pages=597–606 |doi=10.1242/jeb.00792 |pmid=14718503 |doi-access=free |bibcode=2004JExpB.207..597D }}</ref> The first verified occurrence of genetically identical avian twins was demonstrated in the emu.<ref>{{cite journal |doi=10.1111/j.1469-7998.1999.tb01010.x |author1=Bassett, S.M. |author2=Potter, M.A. |author3=Fordham, R.A. |author4=Johnston, E.V. |year=1999 |title=Genetically identical avian twins |journal=Journal of Zoology |volume=247 |pages=475–478 |issue=4 }}</ref> The egg surface is granulated and pale green. During the incubation period, the egg turns dark green, although if the egg never hatches, it will turn white from the [[bleach]]ing effect of the sun.<ref name=e25>Eastman, p. 25.</ref>

The male becomes broody after his mate starts laying, and may begin to incubate the eggs before the clutch is complete. From this time on, he does not eat, drink, or defecate, and stands only to turn the eggs, which he does about ten times a day.<ref name=e25 /> He develops a [[brood patch]], a bare area of wrinkled skin which is in intimate contact with the eggs.<ref>{{cite book|title=The Emu|url=https://books.google.com/books?id=m8ogAQAAMAAJ |year=1956 |author=Royal Australasian Ornithologists' Union |publisher=The Union |page=408}}</ref> Over the course of the eight-week incubation period, he will lose a third of his weight and will survive on stored body fat and on any morning dew that he can reach from the nest. As with many other Australian birds, such as the [[superb fairywren]], infidelity is the norm for emus, despite the initial pair bond: once the male starts brooding, the female usually wanders off, and may mate with other males and lay in multiple nests; thus, as many as half the chicks in a brood may not be fathered by the incubating male, or even by either parent, as emus also exhibit [[Brood parasite|brood parasitism]].<ref>{{cite journal|author1=Taylor, Emma L. |author2=Blache, Dominique |author3=Groth, David |author4=Wetherall, John D. |author5=Martin, Graeme B. |year=2000 |title=Genetic evidence for mixed parentage in nests of the emu (''Dromaius novaehollandiae'') |journal=Behavioral Ecology and Sociobiology |volume=47 |issue=5 |pages=359–364 |jstor=4601755 |doi=10.1007/s002650050677|bibcode=2000BEcoS..47..359T |s2cid=20313464 }}</ref>

[[File:Baby Emu.jpg|thumb|alt=Chicks are camouflaged|Emu chicks have longitudinal stripes that provide camouflage]]

Some females stay and defend the nest until the chicks start hatching, but most leave the nesting area completely to nest again; in a good season, a female emu may nest three times.<ref name="Congress">{{cite book |author=Davies, S.J.J.F. |year=1976 |chapter=The natural history of the emu in comparison with that of other ratites |title=Proceedings of the 16th international ornithological congress |editor1=Firth, H.J. |editor2=Calaby, J.H. |publisher=[[Australian Academy of Science]] |pages=109–120 |isbn=978-0-85847-038-5}}</ref> If the parents stay together during the incubation period, they will take turns standing guard over the eggs while the other drinks and feeds within earshot.<ref name=e26 /> If it perceives a threat during this period, it will lie down on top of the nest and try to blend in with the similar-looking surrounds, and suddenly stand up to confront and scare the other party if it comes close.<ref name=e26>Eastman, p. 26.</ref>

Incubation takes 56&nbsp;days, and the male stops incubating the eggs shortly before they hatch.<ref name="Congress" /> The temperature of the nest rises slightly during the eight-week period. Although the eggs are laid sequentially, they tend to hatch within two days of one another, as the eggs that were laid later experienced higher temperatures and developed more rapidly.<ref name=Maloney2008/> During the process, the [[precocial]] emu chicks need to develop a capacity for thermoregulation. During incubation, the embryos are kept at a constant temperature but the chicks will need to be able to cope with varying external temperatures by the time they hatch.<ref name=Maloney2008/>

Newly hatched chicks are active and can leave the nest within a few days of hatching. They stand about {{convert|12|cm|in|0|abbr=on}} tall at first, weigh {{convert|0.5|kg|oz|1|abbr=on}},<ref name="S. Davies" /> and have distinctive brown and cream stripes for camouflage, which fade after three months or so. The male guards the growing chicks for up to seven months, teaching them how to find food.<ref name="S. Davies" /><ref name="Reader's Digest">{{cite book|title=Reader's Digest Complete Book of Australian Birds|publisher=Reader's Digest Services |isbn= 978-0-909486-63-1|title-link=Reader's Digest Complete Book of Australian Birds |year=1978 }}</ref> Chicks grow very quickly and are fully grown in five to six months;<ref name="S. Davies" /> they may remain with their family group for another six months or so before they split up to breed in their second season. During their early life, the young emus are defended by their father, who adopts a belligerent stance towards other emus, including the mother. He does this by ruffling his feathers, emitting sharp grunts, and kicking his legs to drive off other animals. He can also bend his knees to crouch over smaller chicks to protect them. At night, he envelops his young with his feathers.<ref name=e27>Eastman, p. 27.</ref> As the young emus cannot travel far, the parents must choose an area with plentiful food in which to breed.<ref name=e31 /> In the wild, emus can live for upwards of 10 years but in captivity, they can live up to 20 years.<ref name=HBWA/><ref>Blakers, M., S. Davies, P. Reilly. 1984. The Atlas of Australian Birds. Melbourne, Australia: Melbourne University Press.</ref>

=== Predation ===
[[File:John Gould Emu.jpg|thumb|right|alt=Emu illustration 1848|Emu and chicks, from ''The Birds of Australia'', John Gould, 1848]]

There are few native natural predators of adult emus still extant. Early in its species history it may have faced numerous terrestrial predators now extinct, including the giant lizard ''[[Megalania]]'', the [[thylacine]], and possibly other [[Dasyuromorphia|carnivorous marsupials]], which may explain their seemingly well-developed ability to defend themselves from terrestrial predators. The main predator of emus today is the [[dingo]], which was originally introduced by [[Indigenous Australians|Aboriginals]] thousands of years ago from a stock of semi-domesticated wolves. Dingoes try to kill the emu by attacking the head. The emu typically tries to repel the dingo by jumping into the air and kicking or stamping the dingo on its way down. The emu jumps as the dingo barely has the capacity to jump high enough to threaten its neck, so a correctly timed leap to coincide with the dingo's lunge can keep its head and neck out of danger.<ref name=e29>Eastman, p. 29.</ref> Despite the potential prey-predator relationship, the presence of predaceous dingoes does not appear to heavily influence emu numbers, with other natural conditions just as likely to cause mortality.<ref>{{cite journal |author1=Caughley, G. |author2=Grigg, G.C. |author3=Caughley, J. |author4=Hill, G.J.E. | title = Does dingo predation control the densities of kangaroos and emus? | journal = Australian Wildlife Research | year = 1980 | volume = 7 |issue=1 | pages = 1–12 | doi = 10.1071/WR9800001 |bibcode=1980WildR...7....1C |citeseerx=10.1.1.534.9972 }}</ref> [[Wedge-tailed eagle]]s are the only avian predator capable of attacking fully-grown emus, though are perhaps most likely to take small or young specimens. The eagles attack emus by swooping downwards rapidly and at high speed and aiming for the head and neck. In this case, the emu's jumping technique as employed against the dingo is not useful. The birds try to target the emu in the open ground so that it cannot hide behind obstacles. Under such circumstances, the emu runs in a chaotic manner and changes directions frequently to try to evade its attacker.<ref name=e29 /><ref>''Wedge-tailed eagle (Australian Natural History Series)'' by Peggy Olsen. CSIRO Publishing (2005), {{ISBN|978-0-643-09165-8}}</ref> While full-grown adults are rarely preyed upon, [[dingo]]s, [[Bird of prey|raptors]], [[Perentie|monitor lizards]], introduced [[red fox]]es, feral and domestic dogs, and feral pigs occasionally feed on emu eggs or kill small chicks. Adult males fiercely defend their chicks from predators, especially dingos and foxes.<ref name="iucn status 19 November 2021" /><ref name=HBWA/>

===Parasites===
Emus can suffer from both external and internal [[Parasitism|parasites]], but under farmed conditions are more parasite-free than [[ostrich]]es or [[rhea (bird)|rheas]]. External parasites include the louse ''[[Dahlemhornia asymmetrica]]'' and various other lice, [[tick]]s, [[mite]]s and [[Fly|flies]]. Chicks sometimes suffer from intestinal tract infections caused by [[coccidia]]n [[protozoa]], and the [[nematode]] ''[[Trichostrongylus tenuis]]'' infects the emu as well as a wide range of other birds, causing [[haemorrhagic]] [[diarrhoea]]. Other [[nematode]]s are found in the [[trachea]] and [[Bronchus|bronchi]]; ''[[Syngamus trachea]]'' causing haemorrhagic [[tracheitis]] and ''[[Cyathostoma variegatum]]'' causing serious respiratory problems in juveniles.<ref>{{cite journal |author1=Nemejc, Karel |author2=Lukešová, Daniela |year=2012 |title=The parasite fauna of ostriches, emu and rheas |journal=Agricultura Tropica et Subtropica  |volume=54 |issue=1 |pages=45–50 |doi=10.2478/v10295-012-0007-6  |doi-access=free }}</ref>