The key differences between a rhea and an emu are their size, appearance, lifespan, speed, temperament, and endangered status.
The rhea is the only member of the order Rheiformes, which is found only in South America. Two types of rheas are called the “Greater” and “Lesser” rheas. The greater rhea is the largest of all South American birds! After its ratite relative, the emu is the second-largest living bird in terms of height.