Emu vs Rhea
Distribution and the physical characteristics are of immense importance in exploring the differences between emus and rheas. Taxonomical diversity would be another aspect that provides some distinction between these two, but ecology is almost the same in both emu and rhea. This article aims to explore and emphasize the differences between emu and rhea in some aspects of biology.
Emu, Dromaius novaehollandiae (Order: Casuaryformes) is the only surviving member of this genus and the largest native bird of Australia. They have a home range covering all the state territories of the Australian mainland. They grow up to two metres of height, about 1.5 metres of body length, and 55 kilograms of weight. Emus have three extant subspecies and there are only slight differences among them. They have brown coloured plumage with white patches on it, and those feathers are famous for their softness. Emus can run long distances at a higher speed around 50 kilometres per hour. Their strong legs are extremely helpful to run fast. Emus are omnivorous birds and they can survive without food for more than a couple of weeks. Their mechanical digestion of food is facilitated by an interesting behaviour, which is they eat metals, glass shards, and stones to help the food to squash inside their stomach. They have the ability to swim in case of a flood or crossing a river, but drink only a little amount of water. Usually, emu males and females are similar in size and appearance, they live in large and highly dense colonies, but they walk in couples. However, an emu’s lifespan is 10 – 20 years in wild.
Rhea is the only member the Order: Rheiformes, and live exclusively in South America. There are two species of them with eight subspecies. Greater rhea, Rhea Americana ranges in central and Eastern South America (mainly Brazil) and lesser rhea (R. pennata) ranges in Southern and Southwestern countries (mainly Argentina and Chilli). Their plumage is grey to brown and have a long neck. Their body length is about 1.5 metres and they have a body weight that averages around 40 kilograms. Rheas keep their large wings spread while running, and they can speed up to 60 kilometres per hour. Their strong legs and forwardly directed toes are important for them to run fast on the ground. Usually, they are silent birds, but if provoked they can attack and hurt anyone from their powerful kicks. Rheas are omnivores and prefer fruits, roots, and seeds as well as small animals and sometimes they are carrion feeders. They are communal and their flocks get larger starting from 10 to 100 members in each before breeding season. However, flocks break up mostly into couples or into small groups during mating season. Males are polygamous, keeping two to three females for mating. After they mate, male builds their nest and all females lay eggs on it. Then, males incubate eggs, and sometimes he uses another subordinate male to incubate the eggs. Rheas are known to live more than 20 years in wild.
Difference between Emu and Rhea
|Geographical distribution||Endemic to Australian mainland||Endemic to South America|
|Taxonomic diversity||One species with three subspecies||Two species with eight subspecies|
|Average body weight||55 kg||40 kg|
|Average height||2 m||1.75 m|
|Maximum speed||50 km/h||60 km/h|
|Neck||Shorter than rheas||Longer than rheas|
|Colours||Brown with white patches||Grey to brown plumage|
|Lifespan||10 – 20 years in wild||More than 20 years usually in wild|