The emu, Australia’s largest native bird and the second-largest bird globally, is a flightless species well-adapted to its vast and often harsh environment. This iconic bird is classified as an opportunistic omnivore, meaning its diet is highly flexible and dictated by immediate availability across the continent. Emus inhabit a wide range of ecosystems, from sclerophyll forests and woodlands to semi-arid shrublands and grasslands. Their ability to sustain themselves across such diverse habitats hinges on a varied and adaptable diet.
The Emu’s Primary Wild Menu
The majority of an emu’s diet consists of plant matter, making them predominantly herbivorous. They prioritize consuming parts of plants that offer the highest concentration of nutrients, such as seeds, fruits, and flowers. Emus feed on a wide variety of native species, including the seeds of Acacia and Casuarina trees, as well as the fruits of plants like the Sweet Quandong (Santalum acuminatum).
Fresh green shoots and young grass are favored when available, particularly after rainfall, providing easily digestible nutrients. The consumption of seeds and fruits is ecologically significant because emus act as important long-distance seed dispersers (zoochory). They carry seeds over large distances, contributing to the vegetation dynamics of arid and semi-arid regions.
Animal matter, primarily invertebrates, forms a protein-rich portion of their food intake, especially during breeding season. Emus consume a range of insects and arthropods, including grasshoppers, crickets, beetles, spiders, and moth larvae. This protein source is important for growing chicks and maintaining adult health. Occasionally, they also consume small vertebrates like lizards and rodents.
Essential Digestive Habits and Foraging
Since emus lack teeth, they rely on a powerful digestive mechanism to process the tough, fibrous plant material they consume. They intentionally swallow small stones or pebbles, known as gastroliths, to aid digestion. These gastroliths are housed in the muscular gizzard, where strong contractions grind the food down like a mill.
The size of the ingested stones is specific, with individual gastroliths sometimes weighing up to 45 grams. An adult emu can hold a significant mass of these stones, up to 745 grams, in its gizzard. This mechanical trituration is a requirement for nutrient absorption from hard seeds and tough leaves.
Emus are diurnal, spending much of their day foraging and seeking food sources. They use their long necks to reach vegetation high off the ground, pecking at flowers and seeds. They are also highly adept at locating water, though they possess remarkable drought tolerance. While they can extract moisture from their food, they will drink copious amounts when water is available.
Adaptations to Seasonal and Regional Availability
The emu’s diet directly reflects seasonal availability across the Australian interior, a pattern driven by their nomadic tendencies. In the warmer months, when insect populations boom, emus shift their focus to this protein-rich food source. Their consumption of flowers and fruits is also high during these abundant periods.
During the drier or winter months, when insects become scarce, the diet relies more heavily on seeds, tough herbs, and fresh grass shoots that emerge after localized rain. In arid zones, the birds may migrate hundreds of kilometers, following rain-bearing clouds to find new flushes of vegetation. This mobility allows them to exploit transient resources that appear after unpredictable rainfall.
Emus will consume practically any suitable organic material they encounter. This ecological flexibility, where their menu is dictated by immediate environmental conditions, allows the emu to thrive across nearly the entire Australian continent. They are generalist feeders, a successful strategy for survival in an environment characterized by extreme variability.