It is the females that court the males, and during the mating season, they become physically
more attractive. The female strides around confidently, often circling the male, and pulls its neck back while puffing out
her feathers and crying out a low, monosyllabic sound that has been compared to human drums. These sounds are called "drumming"
or "booming". The deep rumbling sound, with its very low frequency, has properties similar to the infrasounds emitted
by elephants for long distance communication. As the female circles its prospective mate, it continues
to look towards him by turning its neck, while keeping its rump facing him. During this time, the female's cervical air
sac may remain inflated as it calls outs.
During the courtship, both genders start strutting and circling; ruffling out their feathers
and cocking their heads in a shy posture. The male starts a mating dance with slow, snake-like back-and-forth movements of
his head while circling the female. The male needs a lot of patient persuasion to get a conquest, otherwise, the female can
turn very aggressive.
If the male shows interest in the parading female, he will move closer;
the female continues to tantalise its target by shuffling further away and continuing to circle him as before Females are more aggressive than males
during the courting period, often fighting one another for access to mates. If a female tried to woo a male that already had
a partner, the incumbent female will try and repel the competitor by walking towards her challenger and staring in a stern
way. If the male showed interest in the second female by erecting his feathers and swaying from side to side, the incumbent
female will attack the challenger, usually resulting in a backdown by the new female. Some female-female competitions can
last up to five hours, especially when the target male is single and neither female has the advantage of incumbency. In these
cases, the animals typically intensify their mating calls and displays, which increase in extravagance. This is often accompanied
by chasing and kicking by the competing females
Males lose their appetite and construct a rough
nest in a semi-sheltered hollow on the ground from bark, grass, sticks, and leaves. The nests are usually placed in an area
where the emu has a clear view of the surrounds and can detect predators
“Wonder” from “Down Under”
The pair mates every day or two,
and every second or third day the female lays one of an average of 11 (and as many as 20) very large, thick-shelled, dark-green
eggs. The number of eggs varies with rainfall The eggs are on average 5.3 × 3.5 in and weigh around
2 pounds which is roughly equivalent to 10–12 chicken eggs in volume and weight. The first verified occurrence of genetically
identical avian twins was demonstrated in the Emu. 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 bleaching effect of the sun.
The male becomes broody after his mate starts laying, and begins to incubate the eggs before the laying period is complete. From
this time on, he does not eat, drink, or defecate, and stands only to turn the eggs, which he does about 10 times a day. Sometimes
he will walk away at night; he chooses such a time as most predators of Emu eggs are not nocturnal. Over eight weeks of incubation,
he will lose a third of his weight and will survive only on stored body-fat and on any morning dew that he can reach from
Infidelity is the norm for Emus, despite the initial pair-bond: once the
male starts brooding, the female mates with other males and may lay in multiple clutches; thus, as many as half the chicks
in a brood may be fathered by others, or by neither parent as Emus also exhibit brood parasitism.
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. 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. 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 and confront and scare the other party if it comes close.