MadSci Network: Zoology

Re: What is the difference between an emu and an ostrich?

Date: Wed Nov 15 12:25:45 2000
Posted By: Matt Wright, Post-doc/Fellow, Genetics, University College London
Area of science: Zoology
ID: 974171736.Zo

MadSci Answer: Ostrich/Emu Question: What is the difference between an emu and an ostrich?

Hello Melissa,

Ostriches and emus are both members of a family of flightless birds. Other members of this family include the cassowaries (Casuariinae) of New Guinea, emus (Dromiceinae) of Australia, kiwis (Apterygidae) of New Zealand,  rheas (Rheidae) of South America and tinamous (Tinamidae) of the Neotropics, ranging from north-eastern Mexico to Tierra del Fuego.  The extinct groups include moas (Dinornithidae) of New Zealand, elephant birds (Aepyornithidae) of Africa and Madagascar and mihirung birds (Dromornithidae) of Australia.  Except for the tinamou, these birds are entirely flightless and are known collectively as ratites.

Since ostriches and emus are both ratites they possess many similarities.  I have described below the main features of these two birds for you to compare:

THE OSTRICH  (Family – Struthionidae; Species - Struthio camelus)
The adult ostrich stands at an average height of 2.5m (8ft 2in), which makes it the world’s tallest bird species.  Both sexes possess soft and fluffy feathers.  However its plumage is sexually dimorphic: in the male there are distinctively jet black feathers which in females are a ruddy grey-brown colour.  In addition, the males possess loose- textured drooping white feathers on their wings and tail.

The birds have large strong legs (ending uniquely in only two toes), which enable an easy striding gait allowing a top speed when running of 40mph (60 km/h).  It is their great speed in combination with a keen sight that provides them with a means of outpacing any predating animal that might seek to attack them.  The ostriches inhabit landscapes such as desert, semi-desert, and grasslands where the terrain is open enough for speed to be an effective deterrent.  Ostriches are herbivorous foragers and feed via ballistic pecking of leaves, flowers and seeds of a wide variety of plants.

Today, wild ostriches can be found across Africa from Senegal to Ethiopia, and south as far as Tanzania with separate populations in Southern Africa.  The former wild population in the Arabian Peninsula is now extinct.  Ostriches are also now found extensively across the world on farms, where they are bred mainly for their feathers and meat.

THE EMU  (Family – Struthionidae; Species - Dromaius noveahollandiae)
Emus are the worlds second largest flightless bird - the Ostrich being the largest. They are extremely tough birds, being covered with coarse deep brown plumage except for the head and neck which are virtually featherless. It is difficult to distinguish between the sexes but in the breeding season, the hen grows black feathers on her head and the small areas of bare skin on the head turns blue.

The emu has powerful eyesight and keen hearing. Emus are fast, running up to 30 mph (50 km/h) often in an erratic pattern to confuse pursuers. The feet have three toes and are extremely powerful easily capable of killing a human. In their native Australia, they live on open grassland and consequently in the past were persecuted by farmers.

Emus are very hardy and adaptable birds. They have no known diseases that are common to the species. They can thrive in environments ranging from the hot desert to 100 degrees below zero.  Emus are also now farmed for their meat, however, this industry is not as widespread as ostrich farming.

Hope this is of some help.





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