Rheidae – Rheas

This family consists of large, flightless birds known as rheas, native to South America. Due to their appearance and flightless nature, they are often compared to their African relatives, the ostriches, within the order Struthioniformes. Rheas are exceptional runners, capable of reaching high speeds over the open plains and grasslands they inhabit.

Taxonomically, there has been some debate over the number of rhea species. Traditionally, two species are recognized: the greater rhea and the lesser rhea. The greater rhea is the largest of the group and can be found throughout much of eastern and central South America, while the lesser rhea inhabit the southern and western parts of the continent, respectively.

Rheas have a diverse diet that reflects the availability of food sources in their environment. They are omnivorous, feeding on a variety of plants, including leaves, fruits, and seeds, as well as insects, small vertebrates like fish, rodents, reptiles, and small birds. This broad diet allows them to thrive in various ecosystems, from arid scrublands to grassy plains.

Nesting and reproductive behavior in rheas are particularly interesting. Females lay eggs in a communal nest created and guarded by a dominant male. After laying, females may leave to mate again and lay in another male’s nest while the male incubates the eggs and cares for the chicks once they hatch. In some cases, subordinate males are enlisted to help with incubation duties. This system, where males take on the primary role in parenting, is relatively rare among birds and is a notable feature of rheas’ social structure.

Rheas have long been farmed for various products. Their skin is used in the leather industry, their meat is consumed, their feathers are used for decoration and in the fashion industry, and their eggs, which are quite large, are used for crafts and occasionally as a food source.