If you’re ever asked about the largest bird in the world, what would you answer? Ostriches, right? Well, while ostriches are indeed both the largest and the heaviest birds in the world, they’re closely followed by the emu, a similar-looking bird species which is also flightless.
Many people think of emus as a smaller version of the ostriches considering their size and appearance. However, if you examine these ratites closely, you’ll find that they’re more different than you might think.
Emus are not only shorter and lighter than the ostriches but also have smaller eyes, shorter wings, and three-toed feet, unlike the two-toed ostriches. They possess dark bills, unlike the pinkish bills of the ostriches. Moreover, while ostriches are found in Africa, emus belong to Australia. Lastly, the male emus are monogamous and mate with only one female, whereas the male ostriches mate with about 5-7 females in a single season.
In this article, we will learn everything you need to know about distinguishing between ostriches and emus.
Emu Vs. Ostrich: At a glance
Before we get into the details, let’s do a quick study of the differences between emus and ostriches by glancing at the table given below:
|Scientific name||Dromaius novaehollandiae||Two ostrich species belonging to the Struthio genus:·
Common Ostrich (Struthio camelus)·
Somali Ostrich (Struthio molybdophanes)
|Height||50-190 centiemeters (59-75 inches)||Common Ostrich:2.4-1.9 meters (6.2-7.8 feet)
Somali Ostrich:2.7 meters (9 feet)
|Weight||31.5-37 kilograms (69-82 pounds)||Common Ostrich:100-115 kilograms (220-254 pounds)
Somali Ostrich:105 kilograms (231 pounds)
|Speed||48 km/h (30 mph)||Common Ostrich:55-70 km/h (34-43 mph)
Somali Ostrich:64 km/h (40 mph)
|Lifespan||About 10-20 years in the wild, and 35 years in captivity.||About 30-40 years in the wild; up to 75 years in captivity.|
|Location||Australia||Common Ostrich:The sahel and savannahs of Africa located north and south of the equatorial zones.
Somali Ostrich:Horn of Africa (the Somali Peninsula)
|Vocalization||Non-vocal sounds with a low-pitch, including booming and grunting notes.||The male ostriches produce a low, booming call while the females make a hissing noise.|
|Diet||Both emus and ostriches have an omnivorous diet which is primarily plant-based, with insects and other small mammals contributing to it secondarily.|
|Population status||The emus have a stable population which is included in the Least Concern List by the IUCN.||Common Ostrich: Least Concern species
Somali Ostrich: Vulnerable species
|Migration status||Emus don?t migrate long-distance but display nomadic behavior which might or might not be seasonal.||Ostriches are non-migratory birds that might travel to a different place in the case of food scarcity.|
|Eggs laid||About 25 eggs per year.||About 12-18 eggs per year.|
From the table given above, it’s clear that both emus and ostriches belong to separate families and orders. But doesn’t their similar appearance make you wonder if these birds are related to each other?
Well, you’re not really wrong in thinking that. In truth, both emus and ostriches are members of the Ratite family, which is a diverse family containing various extinct and extant flightless birds. All of these birds happen to have small heads, heavy bodies, and legs that are relatively long.
In other words, while emus and ostriches might not be closely related, they’re certainly related to each other tangentially.
Differences in appearance
In the last section, we discussed the relationship between emus and ostriches. However, now, it’s time for us to focus on the differences, not the similarities.
When it comes to emus and ostriches, their physical appearances only help to highlight their similarities. Or do they? How closely have you examined these birds? Perhaps they might be more different from one another than you’d imagine.
Let’s start by exploring what each of these birds looks like, and we’ll proceed to list the differences later.
What do emus look like?
Being quite tall due to their long legs, the emus are ranked the second-tallest birds in the world, right after the ostriches. These birds are also sufficiently heavy and are the fifth-heaviest extant bird in the world.
While their legs and neck are long, their wings are quite short in comparison, which is just as well since it serves other purposes for them. Emus flap their wings when they run, as it helps them in stabilizing their body while moving that fast.
They also possess specialized pelvic muscles to help them run. Their legs have three toes, with sharp claws adorning each toe; these can act as their strongest weapons in a fight. Although their legs are devoid of any hairs, the feet are thick with a cushioned sole to support their running.
The color of their head and neck are pale blue, covered sparsely with black hairs. The rest of their plumage is dull greyish-brown with black tips, giving them a rather shaggy appearance. Emus’ plumage colors can vary according to the environment they live in, providing them a natural camouflage.
In terms of sexual dimorphism, both sexes have identical plumage. However, the females are slightly larger than their male counterparts and also have a wider rump. Additionally, the male’s penis is clearly visible when they urinate or defecate.
What do ostriches look like?
The Ostriches are renowned for being the tallest as well as heaviest bird in the entire world. Just like the emus, ostriches also possess a long neck and legs, with a predominantly black plumage except for their white tail and primaries.
The color of their skin is generally light grey but could have a reddish or pinkish touch in some subspecies. While they possess a small head covered with sparse hairs, their eyes stand out for being quite large. These protruding dark brown eyes are considered to be the largest any terrestrial mammal animal could possess. The bill of these birds is colored in faded pink; it has a broad, flat structure with a hook on the greyish tip.
Ostriches have only two toes on each of their feet, one substantially larger than the other. On the larger toe, you can also see a large, thick nail that has a hoof-like structure. The smaller toe, on the other hand, has no nails. It might sound surprising to you, but the reduced toes of the ostriches are an adaptation to help them run faster.
Both Common and Somali Ostriches share the same physical features. However, the latter possesses a blue neck and thighs that grow brighter in the males during breeding months.
In terms of sexual dimorphism, both sexes of the adult ostriches are quite different from each other. The males are the larger of the two, possessing a primarily black plumage, whereas the females are slightly smaller and have a greyish-brown plumage.
Major differences in appearance
Now, let’s quickly figure out some major physical differences between these two ratites:
- Ostriches are considerably taller than emus, with an average difference of 80 centimeters-1 meter between their respective heights.
- Ostriches are also much heavier than emus. While the mass of emus ranges between 30-40 kilograms, ostriches generally weigh over 100 kilograms.
- The plumage of male ostriches is predominantly black in color, while among the emus, both sexes possess a greyish brown plumage.
- While both emus and ostriches are small-headed birds, the eyes of ostriches are far larger than that of the emus.
- Emus have dark grey bills, while the bills of ostriches are pinkish with faded grey edges.
- Emus are three-toed birds with sharp claws on each toe. On the other hand, ostriches possess only two toes, with only the larger one having a hoof-like nail.
Differences in vocalization
While there are many differences between the appearance of emus and ostriches, in terms of vocalization, they’re quite similar to one another. Both these ratites possess a similar syrinx with simplified muscles, which prevents them from making any vocal sound.
For this reason, they’re both known to produce non-vocal sounds which are loud enough to be heard from several kilometers away. An emu will either produce a rolling grunt or a thumping call with booming notes, regardless of their sex.
However, among the ostriches, the males and females are seen producing different sounds. The males produce a deep, booming noise by inflating their necks and keeping their bills shut. On the other hand, their female counterparts are often seen producing a loud hissing noise by opening their beak slightly.
Differences in habitats
Before we delve deeper into the habitats of emus and ostriches, it is essential to note that both these ratites are quite flexible about their surroundings. They would adjust to almost any surroundings as long as they could find sufficient food and water around.
It is this adaptive nature of these birds that have made it possible to rear them on every continent on Earth except Antarctica.
Where are emus found?
Emus are endemic to Australia. These birds were once known to populate the east coast of the continent quite densely. However, with the spreading agricultural practices in these areas, they have now adapted to living in the arid regions.
The preferred habitats of the emus include the sclerophyll forests and savannahs, as they tend to stay away from the areas with lower precipitation rates and human populations.
While the emus aren’t migratory birds, they do travel long distances on foot in search of new food sources from time to time, always traveling in pairs.
The population that dwells in the western parts of the continent displays movement dictated by the season; they travel north in summers and south during winters.
Where are ostriches found?
Ostriches are endemic to Africa. In the earlier times, these birds were primarily found in East Africa, on both sides of the Sahara, south of the African rainforest belt, and in Asia Minor.
However, nowadays, they prefer to dwell in vast open lands and are more commonly found in the sahels and savannahs of Africa.
On the other hand, the population of the Somali Ostriches is more restricted. These birds dwell within the Horn of Africa and across Kenya and Somalia.
Differences in food preference
If you were paying attention in the last section, you would notice that both emus and ostriches are adapted to living in arid and semi-arid areas and feed on a primary herbivore diet.
Both these ratites eat a number of plant species in their surroundings, both native as well as introduced species. They have a special preference for grasses, fruits, and flowers. The animal-based part of their diet includes insects, arthropods, and small reptiles.
Differences in mating, reproduction, and nesting
Did you know that both emus and ostriches mate for life as a general rule? Both these large ratites take their loyalty towards their partners very seriously; the emu or ostrich couples are rarely known to split.
Let’s learn more about their mating and nesting behavior now.
Emus: breeding and nesting behavior
Both sexes of emus reach their sexual maturity between the age of 18-24 months.
Emu’s breeding season
Although the mating season of emus takes place between the months of April and June, they form their pairs about five months earlier, in December or January. During these months, they establish a nesting territory and defend it from any competition.
They also load themselves up with plenty of food in order to be ready for reproducing when the time comes. Right before the mating period, both the males and females are at their heaviest; the females are more so than their male counterparts.
Mating and nesting
Among the emus, the males have the responsibility of building the nest. They construct a rough nest-like structure on a flat hollow in the ground, not a spherical one.
The area they choose for nesting is generally semi-sheltered and is lined with sticks, grasses, and sticks. In some cases, you can also spot their nests on large rocks.
On the contrary, the females take over the courtship rituals. They stride around prospective males, bending their necks, puffing out their chest feathers, and producing low, monosyllabic sounds. The interested male will then approach the female, swaying their bodies slightly and rubbing their chest against their rump.
Emu’s mating process goes on for a long time, between which the females will lay up to 10-15 eggs on every third day.
These eggs are dark green in color with tiny white speckles on them. Once all the eggs have been laid, the father emu takes up the charge of incubating them.
Like a dedicated father, this male will forget all about food and water, focusing only on turning and heating the eggs (about ten times a day). The incubation period for these eggs lasts up to 56 days.
Even after the eggs have hatched, the father will care for the hatchlings extensively. Although the emu chicks are fully grown by the time they turn six months old, they generally live with their family for another six months.
Ostriches: breeding and nesting behavior
In comparison to the emus, the ostriches mature relatively late in their life. In the wild, both sexes of these birds attain sexual maturity at the age of 4-5 years.
However, on the farms, the females will start laying eggs as early as 2-2.5 years, and the males mature at the age of 3.
Ostrich’s breeding season
The mating season of the ostriches lasts comparatively longer than emus; it begins sometime around March-April and ends in September. Unlike the exclusive couples of the emus, the male ostrich will attract between 2-6 hens and form a harem. However, only one hen will be the major or alpha female with whom they make a pair bond that lasts beyond the mating season.
Mating and nesting
Among the ostriches, the males are the ones that attract females and build a nest for their eggs. Because they mate with more than one female, a large, communal nest is built for them. These nests are nothing more than a simple pit on the ground, scraped by the male.
After the mating period is over, the alpha female will be the first to lay her eggs in the nest and might even discard the eggs of other females during incubation. Their eggs are the largest of all birds; they’re cream in color with a thick shell and glossy appearance.
While the females incubate their eggs during the daytime, the males take over at night. This is due to their plumage coloration; the males can offer better camouflage during nighttime and vice versa.
Ostrich eggs hatch quite early in comparison to other ratites, with their incubation period lasting 45 days. Their hatchlings are quite weak in the first year; only 15% of all the hatchlings survive the year, but those that cross this threshold tend to enjoy a long life.
Emu vs. Ostrich: which bird can run faster?
It is common knowledge that emus and ostriches, two of the largest birds globally, are both fully terrestrial. In other terms, they’re flightless despite being birds and spend their entire lifetime on the ground.
However, while they might lack flight skills, they excel at another means of movement: running. Both these ratites are incredible runners and can outrun most land mammals that are as heavy as themselves. In fact, running is their way of escaping all kinds of dangers in the wild.
But when it comes down to the comparison of their respective speed, ostriches will always outrun emus. While the emus’ average running speed ranges between 45-55 km/h, ostriches can run as fast as 70 km/h.
And there you have it – detailed comparison between emus and ostriches. Today, we’ve learned that while ostriches and emus might appear to be similar birds at first glance, they’re not that similar.
First and foremost, these birds belong to separate families and orders, even though they might both be ratites. Emus are endemic to Australia, while Ostriches belong to the far-away continent of Africa.
Moreover, ostriches are also taller, heavier, and faster than the emus. They possess two toes to support their running, unlike the three-toed emus.