Sources

Where the facts come from

Every factual claim on this site links to its source. This is the full list, and every place where the sources disagree.

How we checked

Each fact was written alongside its source. Our build script stores the source text and, for every fact, checks that the key words and figures really appear in it. 156 of 156 checks passed when this site was last built. All sources were read on 27 Oct 2026. Facts that can change (Red List categories, population trends, population counts and records) carry “checked 27 Oct 2026” next to their source link.

Main sources: the Australian Antarctic Division, the British Antarctic Survey, Smithsonian Ocean, Britannica (its main article text and captions only), New Zealand’s Department of Conservation, WWF-UK, National Geographic, the IUCN Red List and BirdLife International.

When sources disagree

Where trusted sources give different figures, we don’t pick one: we show them all, each with its source.

How many penguin species?

• The Australian Antarctic Division counts 18 species of penguins. 5 of them live in Antarctica, and another 4 live on sub-Antarctic islands. Australian Antarctic Division: Penguins · checked 27 Oct 2026
• The Smithsonian says there is still debate over the number of species, but it’s generally agreed there are between 17 and 19, split into six genera. Smithsonian Ocean: Penguins · checked 27 Oct 2026

Experts still debate where one species ends and the next begins.

How many species live on the Antarctic continent?

• Only five penguin species live on the Antarctic continent: Adélie, emperor, gentoo, chinstrap and macaroni penguins. Australian Antarctic Division: Adélie penguin
• The Smithsonian says only five penguin species ever set foot on the Antarctic continent, and only two, the Adélie and the emperor, live there exclusively. Smithsonian Ocean: Penguins
• The British Antarctic Survey counts 6 major Antarctic species, but says only two, the emperor and the Adélie, are truly native to the continent. Macaroni, chinstrap, gentoo and king penguins live on the warmer sub-Antarctic islands. British Antarctic Survey: Penguins

All three agree that only the emperor and the Adélie are truly Antarctic; they count the visitors differently.

How tall is an emperor?

• The Smithsonian says the emperor stands 4 foot 5 inches (1.35 metres) tall, and gives its maximum size as 51 inches (130 cm) and 88 pounds (40 kg). Smithsonian Ocean: Penguins
• Britannica gives the emperor as 115 cm (45 inches) tall and 25 to 40 kg. Britannica: Penguin
• WWF-UK says emperors stand around 110–130 cm tall, and weigh 23–45 kg depending on the time of year. WWF-UK: Emperor penguins

Penguins don’t stand up straight for a tape measure, and figures depend on how you measure.

How heavy is an emperor?

• The emperor is the largest penguin. The Australian Antarctic Division says adults can weigh up to 40 kg at the start of the breeding season. Australian Antarctic Division: Emperor penguin
• Britannica gives the emperor as 115 cm (45 inches) tall and 25 to 40 kg. Britannica: Penguin
• WWF-UK says emperors stand around 110–130 cm tall, and weigh 23–45 kg depending on the time of year. WWF-UK: Emperor penguins

Emperors gain and lose a lot of weight through the year.

How deep can an emperor dive?

• Emperor penguins mostly hunt 150 to 250 metres down. The Australian Antarctic Division gives the deepest recorded dive as 565 metres. Australian Antarctic Division: Emperor penguin · checked 27 Oct 2026
• The Smithsonian says emperor penguins can reach depths of around 518 m (1,700 feet). Smithsonian Ocean: Penguins · checked 27 Oct 2026
• Britannica says emperors can dive to about 550 metres (1,800 feet), which makes them Earth’s deepest-diving birds. Britannica: Penguin · checked 27 Oct 2026
• The IUCN Red List entry for the emperor penguin gives its lower depth limit as 560 metres. IUCN Red List: Emperor penguin · checked 27 Oct 2026

Records change as more birds are tracked.

How long can an emperor dive?

• Emperor dives usually last 3 to 6 minutes. The Australian Antarctic Division gives the longest on record as 22 minutes. Australian Antarctic Division: Emperor penguin · checked 27 Oct 2026
• The Smithsonian reports a 2018 study that measured an emperor penguin diving for over 32 minutes, the longest bird dive recorded. Smithsonian Ocean: Penguins · checked 27 Oct 2026

The Smithsonian quotes a newer study (2018).

Which penguin is the fastest?

• The Smithsonian says the fastest penguin, the emperor, can reach 9 mph (14 km/h) in a hurry, though it prefers a steady 7 mph. Smithsonian Ocean: Penguins · checked 27 Oct 2026
• Britannica says gentoo penguins are the world’s fastest underwater birds, reaching up to 36 km (about 22 miles) an hour. Britannica: Penguin · checked 27 Oct 2026

Different measures: steady cruising speed versus top speed.

How tall is a little penguin?

• The Department of Conservation calls the little penguin the world’s smallest penguin: just over 25 cm and about 1 kg. NZ Department of Conservation: Little penguin/kororā
• The Smithsonian puts the little (or fairy) penguin at about a foot tall (0.33 m) in one place, and 12 inches (24 cm) in its species notes. Smithsonian Ocean: Penguins
• Britannica gives the blue, or fairy, penguin as about 35 cm tall and about 1 kg. Britannica: Penguin

Even one source gives two figures.

How long does the male emperor incubate the egg?

• The British Antarctic Survey says the male emperor incubates the single egg for 9 weeks without eating, living off a thick fat reserve. British Antarctic Survey: Penguins
• The Smithsonian says the male emperor incubates the egg for roughly 64 days in the dead of winter, huddled with other males while the females feed. Smithsonian Ocean: Penguins

Nine weeks is 63 days, so these are close but not the same.

How long do emperors live?

• The Australian Antarctic Division says some emperors live to more than 40 years, though most don’t live that long in the wild. Australian Antarctic Division: Emperor penguin
• National Geographic gives the emperor’s average life span in the wild as 15 to 20 years. National Geographic: Emperor penguin

Not a true clash: one is the oldest, the other the average.

Is the emperor endangered?

• Emperor penguin: Near Threatened on the IUCN Red List (last assessed 2019). Population trend: decreasing. IUCN Red List: Emperor penguin · checked 27 Oct 2026
• The Australian Antarctic Division’s emperor penguin page gives its conservation status as endangered, and expects a moderately rapid decline over the next three generations because of climate change. Australian Antarctic Division: Emperor penguin · checked 27 Oct 2026
• National Geographic’s emperor penguin page lists it as Near Threatened with a current population trend of ‘stable’. National Geographic: Emperor penguin · checked 27 Oct 2026

The IUCN Red List is the global standard; other pages may use older or national assessments.

Is the royal penguin threatened?

• Royal penguin: Least Concern on the IUCN Red List (last assessed 2021). Population trend: unknown. IUCN Red List: Royal penguin · checked 27 Oct 2026
• The Australian Antarctic Division’s royal penguin page gives its conservation status as near threatened. Australian Antarctic Division: Royal penguin · checked 27 Oct 2026
• A Britannica picture caption calls the royal penguin vulnerable because its breeding area is so small. Britannica: Penguin · checked 27 Oct 2026

Three sources, three different answers.

When did the first penguins live?

• The first penguins evolved roughly 60 million years ago, around 50° south, close to where New Zealand is now. Smithsonian Ocean: Penguins
• Around 66 million years ago, penguins of the genus Waimanu lived in the waters off New Zealand. Smithsonian Ocean: Penguins

The same Smithsonian page gives both dates.

How big were the biggest extinct penguins?

• The Australian Antarctic Division says some extinct penguins were even bigger than emperors, weighing perhaps 100 kg. Australian Antarctic Division: Emperor penguin
• The heaviest known penguin, Kumimanu fordycei, weighed roughly 350 pounds (about 160 kg): about the size of a small bear. Smithsonian Ocean: Penguins

Kumimanu fordycei was described in 2023, after many older estimates.

All sources (36)

• Australian Antarctic Division: Adélie penguin (8 facts)
• Australian Antarctic Division: Chinstrap penguin (5 facts)
• Australian Antarctic Division: Emperor penguin (20 facts)
• Australian Antarctic Division: Gentoo penguin (3 facts)
• Australian Antarctic Division: King penguin (7 facts)
• Australian Antarctic Division: Macaroni penguin (3 facts)
• Australian Antarctic Division: Penguins (7 facts)
• Australian Antarctic Division: Royal penguin (4 facts)
• Australian Antarctic Division: Southern rockhopper penguin (1 fact)
• Australian Antarctic Division: Unusual penguins (3 facts)
• BirdLife International: Northern rockhopper penguin factsheet (2 facts)
• Britannica: Penguin (6 facts)
• British Antarctic Survey: Penguins (3 facts)
• IUCN Red List: Adélie penguin (1 fact)
• IUCN Red List: African penguin (1 fact)
• IUCN Red List: Chinstrap penguin (1 fact)
• IUCN Red List: Emperor penguin (2 facts)
• IUCN Red List: Erect-crested penguin (1 fact)
• IUCN Red List: Fiordland penguin (1 fact)
• IUCN Red List: Galápagos penguin (1 fact)
• IUCN Red List: Gentoo penguin (1 fact)
• IUCN Red List: Humboldt penguin (1 fact)
• IUCN Red List: King penguin (1 fact)
• IUCN Red List: Little penguin (1 fact)
• IUCN Red List: Macaroni penguin (1 fact)
• IUCN Red List: Magellanic penguin (1 fact)
• IUCN Red List: Royal penguin (1 fact)
• IUCN Red List: Snares penguin (1 fact)
• IUCN Red List: Southern rockhopper penguin (1 fact)
• IUCN Red List: Yellow-eyed penguin (1 fact)
• NZ Department of Conservation: Little penguin/kororā (8 facts)
• NZ Department of Conservation: Penguins (2 facts)
• NZ Department of Conservation: Yellow-eyed penguin/hoiho (7 facts)
• National Geographic: Emperor penguin (2 facts)
• Smithsonian Ocean: Penguins (42 facts)
• WWF-UK: Emperor penguins (5 facts)