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What the sources say

Common OstrichStruthio camelus

Every figure, record and mechanism on the Common Ostrich profile was written from a source, and this is the working table behind it: 51 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

San Diego Zoo Wildlife Alliance

Ostrich. San Diego Zoo Wildlife Alliance.

The page sayssprinting in bursts of up to 43 miles an hour
The source saysOstriches can sprint in short bursts up to 43 miles per hour (70 kilometers per hour)
The page sayson two toes
The source saysOstriches are the only birds that have only two toes: all other birds have three or more.
The page saysa kick powerful enough to kill a lion
The source saysit attacks with a ​clawed foot that delivers a kick powerful enough to kill a lion.
The page saysSprints in short bursts of up to 43 mph (70 km/h)
The source saysOstriches can sprint in short bursts up to 43 miles per hour (70 kilometers per hour)Note: stats.superpower field.
The page saysholds a steady 31 mph (50 km/h)
The source saysthey can maintain a steady speed of 31 miles per hour (50 kilometers per hour)Note: stats.superpower field.
The page saysthe only two-toed feet of any bird
The source saysOstriches are the only birds that have only two toes: all other birds have three or more.Note: stats.superpower field.
The page saysA Giant Built on Two Toes
The source saysOstriches are the only birds that have only two toes: all other birds have three or more.Note: Heading; the claim is stated in full in the sentence that follows it.
The page saysNot Actually Hiding in the Sand
The source saysContrary to the popular myth, ostriches do not bury their heads in the sand!Note: Heading; the claim is stated in full in the sentences that follow it.
The page sayssprints in short bursts of up to 43 miles per hour (70 kilometers per hour)
The source saysOstriches can sprint in short bursts up to 43 miles per hour (70 kilometers per hour)
The page saysmaintains a steady 31 miles per hour (50 kilometers per hour)
The source saysthey can maintain a steady speed of 31 miles per hour (50 kilometers per hour)
The page sayscovers 10 to 16 feet (3 to 5 meters) in a single stride
The source saysJust one stride can be 10 to 16 feet (3 to 5 meters) long
The page saysChicks can run at speeds approaching 35 miles per hour at just a month old
The source saysOstrich chicks can run at speeds approaching 35 miles per hour (56 kilometers per hour) at just a month old!
The page saysEvery other bird has three or more toes on each foot; the ostrich has two
The source saysOstriches are the only birds that have only two toes: all other birds have three or more.
The page sayswhich San Diego Zoo Wildlife Alliance says are there "for greater speed."
The source saysits feet have only two toes for greater speed
The page sayswhen an adult ostrich is threatened, it "attacks with a clawed foot that delivers a kick powerful enough to kill a lion."
The source sayswhen an adult ostrich is threatened, it attacks with a ​clawed foot that delivers a kick powerful enough to kill a lion.
The page saysOstriches do not bury their heads in the sand
The source saysContrary to the popular myth, ostriches do not bury their heads in the sand!
The page saysFrom a distance it can look that way
The source saysFrom a distance, it just looks like the ostrich has buried its head in the sand, because only the body is visible.
The page saysan ostrich that senses danger and cannot run away flops to the ground and remains still, head and neck flat in front of it
The source saysit flops to the ground and remains still, with its head and neck flat on the ground in front of it.
The page saysIts pale head and neck blend in with the color of the soil, so only the body stays visible
The source saysBecause the head and neck are lightly colored, they blend in with the color of the soil. From a distance, it just looks like the ostrich has buried its head in the sand, because only the body is visible.Note: The 'so' joins the source's own two statements: the head and neck blend into the soil, and only the body is visible.
The page sayswhen danger threatens an ostrich can get away pretty easily
The source saysWhen danger threatens, ostriches can escape pretty easily by running away.
The page saysIt sprints in short bursts of up to 43 miles per hour (70 kilometers per hour) and can maintain a steady 31 miles per hour (50 kilometers per hour), covering 10 to 16 feet (3 to 5 meters) in a single stride
The source saysOstriches can sprint in short bursts up to 43 miles per hour (70 kilometers per hour), and they can maintain a steady speed of 31 miles per hour (50 kilometers per hour). Just one stride can be 10 to 16 feet (3 to 5 meters) long
The page saysChicks can run at speeds approaching 35 miles per hour at just a month old.
The source saysOstrich chicks can run at speeds approaching 35 miles per hour (56 kilometers per hour) at just a month old!
The page sayswhen an adult ostrich is threatened, it "attacks with a clawed foot that delivers a kick powerful enough to kill a lion."
The source sayswhen an adult ostrich is threatened, it attacks with a ​clawed foot that delivers a kick powerful enough to kill a lion.
The page saysIt can also escape danger pretty easily by running away
The source saysWhen danger threatens, ostriches can escape pretty easily by running away.
The page saysAn ostrich that senses danger and cannot run away drops flat and lies still, head and neck stretched along the ground in front of it
The source saysit flops to the ground and remains still, with its head and neck flat on the ground in front of it.
The page saysIts pale head and neck match the color of the soil, so at a distance only the body stands out, and it looks as though the head has vanished underground
The source saysBecause the head and neck are lightly colored, they blend in with the color of the soil. From a distance, it just looks like the ostrich has buried its head in the sand, because only the body is visible.
The page saysruns in short bursts of up to 70 kilometers per hour, holds a steady 50
The source saysOstriches can sprint in short bursts up to 43 miles per hour (70 kilometers per hour), and they can maintain a steady speed of 31 miles per hour (50 kilometers per hour)Note: vibe.reason (women artists)
The page sayscovers 3 to 5 meters in a single stride
The source saysJust one stride can be 10 to 16 feet (3 to 5 meters) longNote: vibe.reason (women artists)

Source
02

Smithsonian's National Zoo and Conservation Biology Institute

Ostrich. Smithsonian's National Zoo and Conservation Biology Institute.

The page saystallest and heaviest bird alive
The source saysThe world's tallest and heaviest birdNote: Tagline clause; the rank is claimed again in the body.
The page saysGrasslands, savanna, and shrublands of southern and eastern Africa, plus deserts and open woodlands
The source saysCommon ostriches are mostly found in the grasslands, savanna and shrublands of southern and eastern Africa. They are also quite capable of surviving in deserts and open woodlands.Note: stats.habitat field; the source's 'mostly' is kept in the body sentence.
The page saysLeafy greens, flowering plants, roots, grasses and succulents, with occasional small animals, plus swallowed pebbles to grind food
The source saysThey mainly eat leafy greens, flowering plants, roots, grasses and succulents. They also occasionally feed on fallen fruit or small animals such as mice, lizards, frogs, grasshoppers and locusts. ... they swallow sand and pebbles to help grind down food in their stomachs.Note: stats.diet field.
The page saysThe Fastest Thing on Two Legs
The source saysin fact, they are the fastest two-legged animals on Earth.Note: Heading; the claim is stated in full in the sentence right after it.
The page saysthe fastest two-legged animals on Earth
The source saysThese birds are completely flightless but are incredibly swift runners due to their long, strong legs—in fact, they are the fastest two-legged animals on Earth.
The page saysAdult ostriches stand up to nine feet tall
The source saysa fully-grown ostrich can measure up to 9 feet tall
The page saysweigh between 200 and 300 pounds (90 to 136 kilograms)
The source saysAdult ostriches weigh between 200 and 300 pounds (90-136 kilograms)
The page saysthe tallest and heaviest living bird
The source saysThe world's tallest and heaviest bird
The page saysThose feet end in a long, sharp claw on each toe
The source saystwo-toed feet ending with a long, sharp claw on each toe
The page saysCommon ostriches are found mostly in the grasslands, savanna and shrublands of southern and eastern Africa, and can survive in deserts and open woodlands too
The source saysCommon ostriches are mostly found in the grasslands, savanna and shrublands of southern and eastern Africa. They are also quite capable of surviving in deserts and open woodlands.
The page saysliving up to 30 or 40 years in the wild and almost 70 in human care
The source saysIn the wild, ostriches live up to 30-40 years. In human care, some ostriches can live for almost 70 years.
The page saysis completely flightless
The source saysThese birds are completely flightless but are incredibly swift runners due to their long, strong legs—in fact, they are the fastest two-legged animals on Earth.
The page saystags: omnivore
The source saysOstriches are omnivores, although most of their diet is plant-based.Note: Replaces herbivore (#628), whose definition says exclusively.

Source
03

Lesku et al. 2011

Lesku et al. (2011). Ostriches Sleep like Platypuses. PLoS ONE.

The page saysSleeps With Its Eyes Wide Open
The source saysboth eyes were always open though without movementNote: Blockquote lead-in; the claim is stated in full in the sentence that follows it.
The page saysIn deep slow-wave sleep, an ostrich typically sits motionless with both eyes open
The source saysDuring SWS, ostriches typically sat motionlessly with their necks held periscopically above the ground; both eyes were always open though without movement
The page sayslooking more like an alert bird than a sleeping one
The source saysan ostrich in SWS did not look like a typical sleeping animal and instead gave the impression of an alert bird
The page saysOnly when it shifts into REM sleep do its eyes close
The source saysbilateral eye closure was observed only in conjunction with REM sleepNote: 'Only' is the paper's own word: eyes stay open in wakefulness and in SWS.
The page saysits head droop
The source saysThe transition from SWS to REM sleep was marked by bilateral eye closure, rapid eye movements, and a forward falling head
The page saysthose episodes can last up to five minutes, the longest reported for any bird
The source sayscould last up to 5 min (2.3±0.9 min, mean maximum ± s.e.m.), the longest reported for any bird.

Source
04

Smith et al. 2006

Smith et al. (2006). Muscle architecture and functional anatomy of the pelvic limb of the ostrich (Struthio camelus). Journal of Anatomy.

The page saysA dissection study of ten ostriches
The source saysThe pelvic limbs of ten ostriches were dissected
The page saysthe leg's greatest force-generating capacity in the muscles that extend the ankle
The source saysthe highest capacity for force generation was observed in the extensors of the ankle
The page saysmany of them in series with long tendons and so "functionally suited to elastic energy storage"
The source says[muscles] were also in series with long tendons and thus were functionally suited to elastic energy storage.Note: "stretching and recoiling like springs" glosses elastic energy storage, and adds nothing the term does not mean.

Source
05

The IUCN Red List of Threatened Species 2025

Struthio camelus. The IUCN Red List of Threatened Species 2025: e.T45020636A280828427.

The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.