The Emu is the largest bird native to Australia. It is also the second-largest extant bird in the world by height, after its relative, the Ostrich. The Emu is common over most of mainland Australia, although it avoids heavily populated areas, dense forest, and arid areas.
The soft-feathered, brown, flightless birds reach up to 7 ft in height. They have long thin necks and legs. Emus can travel great distances at a fast, economical trot and, if necessary, can sprint at 50 km/h for some distance at a time. Their long legs allow them to take strides of up to 9 ft. They are opportunistically nomadic and may travel long distances to find food; they feed on a variety of plants and insects, but have been known to go weeks without food. They also ingest stones, glass shards and bits of metal that help squash food in the digestive system. They drink infrequently, often once every day or two, and ingest copious fluids when the opportunity arises. Emus will sit in water and are also able to swim. They are curious and nosy animals who are known to follow and watch other animals and humans. Emus do not sleep continuously at night but in several short stints sitting down.
Emus have a nail on their toes, akin to a knife, which is used in kicking away predators and opponent Emus. Their legs are among the strongest of any animals, allowing them to rip metal wire fences. They are endowed with good eyesight and hearing, which allows them to detect predators in the vicinity. The plumage on an eye varies regionally, matching the surrounding environment and improving its camouflage. The feathers allow the Emu to prevent heat from flowing into the skin, permitting it to be active during the midday heat.