Birds · Rheiformes · Rheidae

Greater Rhea

Rhea americana

Near Threatened

It could become endangered in the near future if current threats go unchecked. See full glossary

It is the largest bird in the Americas. It breeds under a reversed polyandrous system: several females lay in the same communal nest, but it is the male that does the incubating.

Weight

30 kg – 40 kg

Size

up to 1.7 m

Lifespan

12 years

Diet

Omnivore

Combines animal and plant food depending on availability.

Activity

Diurnal

Active mainly during the day.

Social structure

Herd

Lives in large groups as a strategy against predators.

Sighting difficulty

Moderate

GrasslandOmnivore Diurnal In herds Near Threatened Bird Grassland

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Fun facts

It is the largest bird in the Americas.
It breeds under a reversed polyandrous system: several females lay in one nest, which the male alone incubates.
A communal nest may hold as many as 80 eggs from several females.

Life cycle & biology

Skeleton type: Vertebrate - non-pneumatised bony skeleton, flightless bird (ratite)
Habitat & environment: Open grassland, savannah, scrub and wetland of eastern and central South America
Birth weight: No precise weight reported (it comes to 60-70% of the egg's weight); the chick has dark lengthwise stripes
Size at birth: Precocial, with grey down and dark lengthwise stripes, able to move almost at once
Sexual maturity: 14 months (though effective breeding usually starts at around 2 years)
Gestation / incubation: 29-43 days, incubated by the male alone
Litter / clutch size: 5 to 10 eggs per female; communal nests may hold as many as 80 from several females
Lifespan in captivity: Documented record of up to 40 years in captivity

Sources consulted: BioDB; Study.com; Idaho Falls Zoo; Animalia.bio; Ark Encounter; Animal Diversity Web; A-Z Animals; New World Encyclopedia; PMC (seasonal hormone study)