What does a running rhea do with its long wings?

Holds them out to steer and balance

Folds them flat and never moves them

Rhea

Q: How to identify Rhea?

Compare the silhouette, bill shape, tail length, wing bars and markings around the eyes. The same small brown bird at your feeder can look quite different in breeding plumage, winter plumage or its first year. Bird Identifier: upload a photo and compare the visible details.

Q: What does Rhea eat?

Rheas are omnivores. They mostly eat plants, seeds and fruits, plus insects and, now and then, a small animal like a lizard!

Q: How fast can a rhea run?

Bird experts say rheas can run at more than 60 km/h, though we found no study that has timed one with instruments. When chased they swerve in zig-zags, holding one wing up like a sail to steer.

Q: What is the difference between a rhea and an ostrich?

Rheas live in South America, ostriches in Africa. A greater rhea stands up to about 1.7 m and weighs 15–36 kg, while an ostrich can reach 2.7 m and 90–130 kg. Rheas have three toes, ostriches two, and in rheas only the dad sits on the eggs.

Q: Do rheas bury their heads in the sand?

No. A frightened rhea runs off in zig-zags or crouches flat in tall grass and keeps still. The head-in-the-sand story is an old ostrich myth, and ostriches don’t do it either.

Q: Do male rheas really raise the chicks alone?

Yes. Several females lay in one male’s nest, then leave. He sits on the eggs for about 6 weeks and guards the striped chicks for 4–6 months. A young male sometimes helps by sitting on a second nest, and on farms males even adopt chicks that aren’t theirs.

Q: Are rheas endangered?

The greater rhea is listed as Near Threatened and is declining, mainly because grassland is being turned into farmland and because it is hunted. Its smaller cousin, the lesser rhea, is Least Concern worldwide but also declining.

Q: Can rheas fly?

No. Rheas are flightless, but their wings are unusually long for a flightless bird. They use them to steer and balance when running, and in courtship displays.

Q: Why are there wild rheas in Germany?

In 2000, 7–12 rheas escaped from an enclosure near Lübeck. They survived the winters and bred, and by 2017 there were about 250. Several hundred now live between Lake Ratzeburg and the Schaalsee, and they have been hunted since 2019.

Q: Why is it called a rhea?

Scientists named the genus Rhea, probably after Rhea, the mother of Zeus in Greek myth. In the Guaraní language of South America the bird is called ñandú.

Rhea americana

The greater rhea (Rhea americana) is a large flightless bird of the grasslands and savannas of eastern and southern South America, and the continent’s largest bird. It eats mostly leaves, seeds and fruit, runs in sharp zig-zags with its long wings held out, and lives in groups outside the breeding season. Males build the nest, sit on eggs laid by several females and raise the striped chicks on their own.

Also known as Common rhea, Grey rhea, Ñandú

Rhea abilities

60+ km/h reported top speed
When chased, a rhea swerves hard from side to side, holding a wing out like a sail or rudder to turn.
- Hudson wrote that a hard-pressed rhea turns “frequently and rapidly at right angles”, leaving many a horse behind.
- Darwin saw rheas set off with their wings spread, “like a vessel” making “all sail”.
- Bird experts give a top speed of more than 60 km/h. We found no study that has timed one with instruments.
- The smaller lesser rhea is said to be even faster, but it tires sooner.
Reported top speeds
Greater rhea60+ km/h
Ostrich70 km/h
Emu48–50 km/h
Short sprints. Ostrich and emu figures come from zoo fact sheets.
Sources [2, 4, 7, 13, 15, 20, 21]
≈42 days on the nest, alone
One male sits on eggs laid by several females, then guards the striped chicks on his own for months.
- He stays with the eggs for about 42 days and sits on them up to 97.5% of the time, slipping away only in the hottest hours.
- Most nests hold 20–30 eggs. Very big clutches, over 30–35 eggs, hatch worse.
- After hatching he guards the chicks for 4–6 months and charges at anything that comes too close, even horses and people.
- It is hard work: fewer than 20% of males try to nest in a season.
Eggs in one rhea nest
Most nests (Argentina)20–30
Biggest counted56
Darwin’s nests, 183322–27
Each nest holds eggs from several females.
Sources [2, 4, 7, 18, 22, 23]
749 booms in 8 days
Rheas are mostly quiet, but in the breeding season males give a deep booming call that is hard to pin down.
- One group of rheas at a zoo in Mato Grosso, Brazil, gave 749 booming calls in 8 days, most in the first 4 hours after sunrise and some at night.
- Hudson described the sound as a “ventriloquial” booming. Darwin first thought it came from a wild beast.
- The rhea’s voice box (syrinx) is more complex than in other ratites.
- The German nature group NABU says the call sounds roughly like “nan-du”.
Sources [4, 7, 8, 10, 11, 24]
3 toes per foot
Long legs and three toes make the rhea a born runner. Ostriches, the only two-toed birds, run on just two.
- Rheas, like emus, have three toes on each foot and no hind toe.
- Ostriches are the only birds with just two toes.
- Built for open grassland: Hudson noted that rheas sometimes trip when tall grass is tied together by twining plants.
Toes per foot
Greater rhea3
Emu3
Ostrich2
Sources [2, 4, 13, 25]
2–12 females courted by one male
To win a harem, a male spreads his long wings, shakes his neck and runs at the females.
- He courts 2–12 females, who all lay their eggs in his nest.
- In a Brazilian study, harem males made the open-wings display about 13–15 times an hour.
- Courtship peaks while the harem is forming, and males drive rival males away.
- The same wings-out pose becomes a threat when a dad charges an intruder.
Sources [2, 4, 12, 26]
2–20 birds in a groupStill debated
Rheas often feed in groups. Each bird can then spend less time on lookout and more time eating.
- Rheas feed alone or in groups of 2–20. A typical group in the Argentine pampas had about 8 birds.
- A rhea feeding alone spends more time watching and less time eating than one in a group.
- Whether bigger groups spot predators sooner is still argued. One study found the group as a whole was not more watchful, while a computer model suggests group scanning could help.
- Encyclopedias say rheas often graze alongside deer and other plant-eaters, but we found no study that has measured this.
Sources [5, 6, 27, 28, 29]
0 heads in the sand
Instead of running, a rhea may crouch flat in tall grass and keep still until danger has passed.
- Hudson found hiding rheas lie so close that they “will not rise until almost trodden on”.
- Darwin watched rheas squat out of sight in a bed of tall rushes.
- When an eagle or a caracara flies over, a dad crouches and gives a loud snorting cry, and his chicks dash under his wings.
- Rheas never bury their heads in sand. Even the ostrich version of that story is a myth.
Sources [4, 7, 13]

Tap a pin on the model or a part below.

- Mostly a plant-eater. In grassland in Argentina, rheas preferred broad-leaved plants, especially clover-like legumes, over grasses.
- It also picks up seeds, fruit, roots and insects, and now and then a small animal such as a lizard.
- It swallows small stones, which help grind up tough food in the stomach.
Sources [1, 2, 3]
- Standing tall on open plains, a rhea can see a long way over the grass.
- A rhea feeding alone spends more time looking up and less time eating than one in a group.
- Darwin found lesser rheas so wary that they seemed to spot people before people could make them out.
Sources [4, 5, 6, 7]
749 booms in 8 days
- Only males boom, as part of courtship. Adults of both sexes hiss when threatened.
- The voice box (syrinx) is more complex than in other ratites, and adult males have a partly bony piece inside it.
- Chicks whistle a lot, but their calls fade and stop by about 7 weeks old.
Sources [8, 9, 10, 11]
- Unusually long for a flightless bird. Rheas hold them out like rudders to dodge and to keep their balance while running.
- A hard-pressed rhea often raises one wing “like a great sail” and turns sharply.
- Males spread them wide to court females, and to charge at anything that comes near their chicks.
- Chicks shelter under their dad’s wings when a hawk flies over.
Sources [2, 4, 12]
3 toes per foot
- Three toes on each foot and no hind toe. Ostriches are the only birds with just two.
- Broad, band-like scales run down the front of the leg. Lesser rheas have small net-like scales instead, and feathers on the upper leg.
- Long, strong legs carry it across open country at more than 60 km/h.
Sources [2, 13, 14, 15]
- Loose, shaggy, mostly grey plumage. The naturalist W. H. Hudson thought it matched the haze on the plains, which made rheas hard to see.
- No showy tail plumes like an ostrich.
- In the breeding season males get a dark collar at the base of the neck. Males are usually bigger and darker than females.
Sources [2, 4, 7]
≈62 h for seeds to pass through
- In captive rheas, food took about 62 hours on average to pass through, so seeds can travel a long way before they are dropped.
- Some seeds sprouted better or faster after the trip. Others were ground up and destroyed.
- Scientists warn that fewer rheas could mean fewer seeds carried far, which may affect plants that rely on them.
Sources [16]
20–30 eggs in most nests
- A shallow scrape on the ground. Males often choose spots hidden by shrubs.
- Several females lay in the same nest. Most nests hold 20–30 eggs, and the most counted in one Argentine study was 56.
- Each egg weighs about 440–620 g and is golden-yellow when fresh, fading towards white.
- Tegu lizards sometimes sneak away with an egg while the dad stays put.
Sources [4, 17, 18, 19]

Real rheas

Photos from Wikimedia Commons. Some of them can repaint the 3D model.

Greater rheaShaggy grey plumage with black at the base of the neck and between the shoulders, and whitish underparts. Breeding males get a darker collar.Near Threatened · decreasingGreater rhea in Encontro das Águas State Park, Pantanal, Brazil. Photo: Giles Laurent, CC BY-SA 4.0
Greater rhea in the Pantanal, BrazilPhoto: Charles J. Sharp, CC BY-SA 4.0
The head: big eyes on a long, slim neckPhoto: Michael Palmer, CC BY-SA 4.0
Dad with chicksChicks are grey-brown with dark stripes along the back, which are gone by about 5 months. A dad is often seen leading 20 or more.Dad alone looks after them for 4–6 monthsA dad with a big group of chicks, Brasília. Photo: Romério Cunha (Palácio do Jaburu), CC BY 2.0
A striped chick resting in the grassPhoto: Warren Garst (Colorado State University Libraries), CC BY-SA 4.0
A clutch of eggs in a nest scrapePhoto: J. Rzadkowski, CC BY-SA 3.0 DE
White (leucistic) rheaThe same species with white feathers: most of the usual grey colour is missing. White rheas are rare. They turn up in zoos and on farms, and one was photographed in the wild flock in northern Germany.A rare colour form, not a separate speciesA white rhea with a grey one near Utecht, Germany. Photo: Gregor Rom, CC BY-SA 4.0
Wild rheas in winter in Mecklenburg-Vorpommern, GermanyPhoto: Sabrina Vincent, CC BY-SA 4.0
Darwin’s rhea (lesser rhea)A separate, smaller species, Rhea pennata, about 1 m tall: brown feathers tipped with white, feathers halfway down the legs and small net-like leg scales.Least Concern · decreasingDarwin’s rhea (lesser rhea) in Torres del Paine, Chile. Photo: Ian Rutherford, CC BY 2.0

Rhea by the numbers

Measured by scientists, zoos and wildlife agencies, with comparisons you can picture.

Height: Up to 1.7 m; standing tall; males are usually bigger; An ostrich can reach 2.7 m⁠[3, 24, 2, 13]
Weight: 15–36 kg; adults; South America’s heaviest bird; An ostrich weighs 90–130 kg⁠[2, 3, 34, 13]
Top speed: 60+ km/h; reported, while zig-zagging⁠[15, 13]; Rhea60 km/hOstrich70 km/h
Eggs per nest: 20–30; usually, from several mums; up to 56 counted⁠[18]
Egg weight: 440–620 g; golden-yellow when fresh; About the weight of an emu egg⁠[19, 4, 20]
Dad on the nest: ≈42 days; sitting up to 97.5% of the time⁠[22]
Chick care: 4–6 months; by dad alone⁠[22]
Seed trip: ≈62 h; for food to pass through (captive rheas)⁠[16]
Group size: 2–20; birds; a typical group has about 8⁠[27]
Lifespan: 13+ yrs; known; the maximum is not yet established⁠[35]

Rhea myths and facts

Tap Myth or Fact for each claim, then check the answer.

0 of 8 answered

“Rheas are a kind of ostrich.”
“Rheas bury their heads in the sand when they are scared.”
“Rhea dads sit on the eggs and raise the chicks on their own.”
“All the eggs in a rhea nest come from one mother.”
“Rheas can swim.”
“Rheas are silent birds.”
“Wild rheas live in Germany.”
“Some people see a rhea in the night sky.”

Rhea records

Superlatives and record holders, each checked against its source.

Largest bird in South America
up to 1.7 m
Greater rhea
and up to about 36 kg; the continent’s tallest and heaviest bird⁠[33, 2, 3, 34]
Biggest nest in an Argentine study
56 eggs
One rhea dad
most nests held 20–30⁠[18]
Booming marathon
749 booms
A rhea group at a zoo in Mato Grosso, Brazil
recorded in 8 days⁠[11]
Oldest rhea pictures
12,000–8,000 BC
Rock paintings in Piauí, Brazil
as reported by Birds of the World⁠[33]
A bird named after Darwin
1837
Rhea darwinii (now Rhea pennata)
named by John Gould from a bird Darwin’s crew had already cooked⁠[14, 7]

Rhea from egg to adult

From a golden egg to a grown-up rhea in about two years, with dad in charge of the first months.

Late winter
Flocks split up
Males chase rivals, twist necks in fights and start booming to attract females.⁠[4, 27]
Spring
Harem and nest
A male courts 2–12 females with wing displays and scrapes a nest in a hidden spot.⁠[2, 12, 17]
Days 1–10
Egg drop-off
Each female lays an egg about every 2 days in the dad’s nest. Laying lasts about 8–9 days.⁠[19]
≈6 weeks
Dad on duty
He sits on the eggs up to 97.5% of the time and leaves only in the hottest hours. Full incubation takes about 36–40 days.⁠[22, 19, 35]
Hatch day
All at once
The chicks hatch within hours of each other. In one nest, 9 chicks hatched in under 5 hours.⁠[19]
First weeks
Whistling chicks
Striped chicks whistle to keep in touch and go quiet by about 7 weeks. When a hawk flies over they run under dad’s wings, and one brood was even seen hiding in an armadillo burrow.⁠[8, 4, 34]
4–7 months
Leaving dad
Dad guards the chicks for 4–6 months, sometimes up to 7. Their stripes are gone by about 5 months.⁠[22, 19, 12]
≈2 years
Grown up
Young rheas roam in groups until they are about 2 years old and ready to breed.⁠[12, 3]
13+ years
A long life
Rheas are known to live at least 13 years. Nobody knows yet how long they can live.⁠[35]

Rhea vs ostrich vs emu

Three big flightless runners on three continents. Check the toes and who sits on the eggs.

Greater rhea vs ostrich vs emu
	Greater rhea	Ostrich	Emu
Lives in⁠[2, 41, 21]	South America	Africa	Australia
Height⁠[3, 13, 20]	Up to 1.7 m	Up to 2.7 m	1.5–1.9 m
Weight⁠[2, 3, 13, 20]	15–36 kg	90–130 kg	30–55 kg
Toes per foot⁠[2, 13, 25]	3	2	3
Wings⁠[2, 41, 21]	Long; used like rudders	Large; used like rudders and to keep cool	Tiny; under 20 cm
Top speed (reported)⁠[15, 13, 20, 21]	60+ km/h	70 km/h	48–50 km/h
Egg weight⁠[19, 13, 20]	440–620 g	≈1,500 g	450–650 g
Who sits on the eggs⁠[22, 13, 21]	Dad alone	Main hen by day, male by night	Dad alone
Incubation⁠[35, 19, 13, 21]	≈36–40 days	42–46 days	≈56 days
IUCN status⁠[30, 42]	Near Threatened	Least Concern	Least Concern

All three are ratites, but DNA shows they are not each other’s closest relatives: the ostrich line split off first.

Are rheas endangered?

Not yet, but the greater rhea is slowly losing ground as South America’s grasslands turn into farmland.

IUCN Red List

Near Threatened (NT)

Population decreasing

Still found across a huge range, but suspected to be declining by roughly 20–29% over three generations (about 33 years), mainly because of habitat loss and hunting. It has disappeared from Ceará and Rio Grande do Norte in north-east Brazil, where reintroduced birds now live in parts.⁠[30]

IUCN Red List, assessed 2022 (BirdLife International)

Threats

Grassland turned to crops51% vs <5%
In one study in the Argentine pampas, rheas used 51% of a grassland site but less than 5% of a cropland site, and were several times more common in grassland.⁠[43, 30]
Hunting and egg collecting50,000+
Skins traded in 1980 alone. Rheas are still hunted for meat, eggs are collected for food, and feathers end up as dusters.⁠[30, 2]
Farm chemicals≈4×
Feathers of rheas living among intensive crops held about four times more long-lasting pollutants than those of rheas on cattle ranches.⁠[44]
Fences
Rheas don’t jump fences (they squeeze underneath), so fencing can block their movements.⁠[33]

What’s helping

Grazing land and grassland
Rheas do best where pastures and native grassland remain. Experts call for keeping these habitats and linking patches with corridors.⁠[45, 30]
Training for the wild
Captive-bred rheas learn to fear predators before release. Trained birds become more cautious, and trained females wander less.⁠[46, 47]
Trade rules
International trade is controlled under CITES Appendix II, so exports need permits.⁠[30, 2]

Rhea relatives

Lesser rhea (Darwin’s rhea)Least Concern
Least Concern worldwide (2022) but declining, mainly from hunting, egg collecting and habitat loss. It is listed as Critically Endangered in Peru, Vulnerable in Argentina and Endangered in Chile.⁠[32]

Darwin and the rhea

On the voyage of the Beagle, Charles Darwin chased a rumour about a second, smaller rhea, and almost lost it to the cooking pot.

Aug 1833
A rumour at the Río Negro
Gauchos told Darwin about a rare, smaller rhea, the “Avestruz Petise”, with shorter legs feathered further down.⁠[7, 14]
Sep–Oct 1833
Counting eggs
Near Bahía Blanca he found nests with 22, 22, 22 and 27 eggs, and learned that several females lay in one nest while the male hatches them.⁠[7]
Dec 1833–Jan 1834
Oops, dinner
At Port Desire, a shipmate, Mr Martens, shot a rhea. Darwin took it for a young common rhea, and it was cooked and eaten before he remembered the rumour.⁠[7, 14]
Back in London
Rebuilt from leftovers
The head, neck, legs, wings, many feathers and much of the skin had been kept, and a nearly complete specimen was put together in London.⁠[7, 14]
1834
A French name first
The French naturalist Alcide d’Orbigny, who had searched for the bird in vain, proposed the name Rhea pennata.⁠[14, 15]
1837
Named after Darwin
John Gould described the bird as Rhea darwinii. Darwin noted that the two rheas replace each other around the Río Negro.⁠[14, 7]
Today
Lesser rhea
Because d’Orbigny’s name came first, scientists now call it Rhea pennata, the lesser or Darwin’s rhea. It lives in Patagonia and the high Andes.⁠[15, 32]

Rhea quiz

12 questions. Every answer is somewhere on this page.

Question 1 of 12Score 0

Which continent is the greater rhea’s native home?

Rhea field notes

Diet, food web, safety and badges from the Snappit field guide.

Diet & Feeding

Rheas are omnivores. They mostly eat plants, seeds and fruits, plus insects and, now and then, a small animal like a lizard!

Primary Foods

Broad-leaved plants
Clover-like legumes
Seeds
Fruits
Insects
Foraging Method: Foraging

Age differences: Young chicks eat more insects for protein, adults are more herbivorous.

Ecological connections

PumaEaten by
Can prey on adult rheas and chicks.
JaguarEaten by
Can also prey on rheas.
South American LocustEats
A common insect prey item.
American NightshadeEats
Consumes its berries and leaves.

Safety

Danger 2/5 · Low

Watch quietly from a distance and never try to feed or chase wild animals. A dad with chicks may charge at anything that comes too close.

Traits

Collections

Birds

Classification

Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Rheiformes
Family: Rheidae
Genus: Rhea

Also known as

Common rhea · Grey rhea · Ñandú · Ema (Portuguese) · Nandu (German) · American Rhea · Greater Rhea · Rheas

Sources for these rhea facts

49 studies and references · checked Oct 16, 2026

Frequently Asked Questions

How to identify Rhea?

Compare the silhouette, bill shape, tail length, wing bars and markings around the eyes. The same small brown bird at your feeder can look quite different in breeding plumage, winter plumage or its first year. Bird Identifier: upload a photo and compare the visible details.

How long is Rhea?

125-150 cm

What is Rhea's wingspan?

150-180 cm

How much does Rhea weigh?

15-36 kg

How long does Rhea live?

10-15 years

What does Rhea eat?

Rheas are omnivores. They mostly eat plants, seeds and fruits, plus insects and, now and then, a small animal like a lizard!

Where is Rhea usually found?

Grasslands and savannas

How fast can a rhea run?

Bird experts say rheas can run at more than 60 km/h, though we found no study that has timed one with instruments. When chased they swerve in zig-zags, holding one wing up like a sail to steer.

What is the difference between a rhea and an ostrich?

Rheas live in South America, ostriches in Africa. A greater rhea stands up to about 1.7 m and weighs 15–36 kg, while an ostrich can reach 2.7 m and 90–130 kg. Rheas have three toes, ostriches two, and in rheas only the dad sits on the eggs.

Do rheas bury their heads in the sand?

No. A frightened rhea runs off in zig-zags or crouches flat in tall grass and keeps still. The head-in-the-sand story is an old ostrich myth, and ostriches don’t do it either.

Do male rheas really raise the chicks alone?

Yes. Several females lay in one male’s nest, then leave. He sits on the eggs for about 6 weeks and guards the striped chicks for 4–6 months. A young male sometimes helps by sitting on a second nest, and on farms males even adopt chicks that aren’t theirs.

Are rheas endangered?

The greater rhea is listed as Near Threatened and is declining, mainly because grassland is being turned into farmland and because it is hunted. Its smaller cousin, the lesser rhea, is Least Concern worldwide but also declining.

Can rheas fly?

No. Rheas are flightless, but their wings are unusually long for a flightless bird. They use them to steer and balance when running, and in courtship displays.

Why are there wild rheas in Germany?

In 2000, 7–12 rheas escaped from an enclosure near Lübeck. They survived the winters and bred, and by 2017 there were about 250. Several hundred now live between Lake Ratzeburg and the Schaalsee, and they have been hunted since 2019.

Why is it called a rhea?

Scientists named the genus Rhea, probably after Rhea, the mother of Zeus in Greek myth. In the Guaraní language of South America the bird is called ñandú.