Ostriches belong to a group of birds called the ratites, from ratis , the Latin word for raft. Being flightless, these birds don't have a keel bone with a lot of heavy wing muscles attached to it (which is why they all lack white meat), so their breastbones are flat and raft-like. The group includes the tiny kiwi bird of New Zealand, the bony-headed cassowary of New Guinea and several extinct species, including the elephant bird of Madagascar, which weighed nearly half a ton.
The ratites that are being considered as food sources are the ostrich, the emu and the rhea. Their flesh tastes more like red meat than poultry, partly because they browse on grasses, just like sheep and cattle.
Ostriches, which have been around for at least 7 million years, are the largest living birds; males may be nine feet tall and weigh more than 350 pounds. In their South African home, they live in flocks of from five to 50, usually grazing in the company of zebras and antelopes. They can run 40 miles an hour.
Their long necks and ability to go without water for a long time gave them their scientific name: Struthio camelus. The myth that ostriches bury their heads in the sand to avoid trouble probably arose because they sometimes lie on the ground with their necks outstretched to avoid being seen.
The emu is the second largest living bird, reaching five feet in height (they have distinctly shorter necks than ostriches) and weighing 100 pounds or more. If anything, emus have an even more preposterously dignified air than ostriches. In Australia, their fat (emu oil) is considered to have medicinal value.
The four-foot-high rhea has been described as a duck's head on a turkey's body on a stork's legs. In its native South American ranges, it grazes side by side with deer. Unlike ostriches and emus, rheas will never be the darlings of Las Vegas because they lack plumes.