---
title: "What the sources say about the Emperor Penguin | AnimalTracks.wiki"
description: "57 claims from the Emperor Penguin profile, each beside the words of the source that backs it."
image: "https://animaltracks.wiki/images/animals/emperor-penguin-1.webp"
canonical: "https://animaltracks.wiki/animals/emperor-penguin/sources/"
---

# What the sources say about the Emperor Penguin (*Aptenodytes forsteri*)

> 57 claims from the Emperor Penguin profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Emperor Penguin](https://animaltracks.wiki/animals/emperor-penguin/)

## Aptenodytes forsteri (emperor penguin). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Aptenodytes_forsteri/

| The page says | The source says |
| :--- | :--- |
| Emperor penguins stand 101 to 132 centimeters tall | standing 101 to 132 cm tall |
| They gain and lose weight rapidly across the breeding and feeding seasons | They gain and lose weight rapidly during breeding and feeding seasons. |
| eating mostly fish, crustaceans and molluscs | Emperor penguins are carnivorous and primarily feed on fish, crustaceans, and molluscs. |
| from the waters around Antarctica | They feed in the open waters of the ocean surrounding Antarctica, or underneath sea ice. |
| Which prey is plentiful varies from place to place, but some research has found Antarctic silverfish among their most frequently eaten | Prey abundance varies from location to location, but some research has found that the Antarctic silverfish (Pleuragramma antarcticum) is one of the most frequently consumed species. |
| with Nototheniidae fish a staple | Fish from the family Nototheniidae are also consumed as a staple of their diet. |
| Antarctic krill and glacial squid eaten regularly | Molluscs such as the glacial squid (Psychroteuthis glacialis), hooked squid (Kondakovia longimana), and the Antarctic krill (Euphausia superba) are also eaten regularly. |
| Antarctic krill | the Antarctic krill (Euphausia superba) are also eaten regularly. |
| glacial squid | Molluscs such as the glacial squid (Psychroteuthis glacialis), hooked squid (Kondakovia longimana), and the Antarctic krill (Euphausia superba) are also eaten regularly. |
| A rough, spiky-textured tongue helps them catch and eat slippery fish and squid | Emperor penguins have a rough and spiky-textured tongue, which helps them catch and eat slippery fish and squids more easily. |
| breed along the Antarctic coastline between 66 and 78 degrees south | In breeding months (April to November), emperor penguin colonies are found between 66° and 78° south latitude, along the Antarctic coastline. |
| winter temperatures fall as low as minus 40 degrees Celsius with wind chills reaching minus 60 | Winter temperatures there range from -40 to 0°C, with wind chills reaching -60°C. |
| Killer whales and leopard seals have been seen preying on emperor penguins | Killer whales (Orcinus orca) have been observed to prey on emperor penguins, sometimes harassing them for fun. ... Leopard seals (Hydrurga leptonyx) are also marine predators of penguins, and have been observed to kill emperor penguins. (note: 'sometimes' qualifies the harassment clause, which the page does not repeat; 'adults' and 'in open water' were cut because the source names neither) |
| skuas are known to steal and eat their eggs and chicks | Seabirds called skuas (Stercorarium parasiticus) are also known to steal and eat emperor penguin eggs and chicks. |
| Most dives are shallow and fairly quick, which makes it harder for predators to reach them | Most emperor dives are shallow and fairly quick, which makes it harder for predators to reach them before they are out of the water again. |
| countershading, a dark back and pale belly, makes swimming penguins harder to make out | With black backs and white bellies, emperor penguins are countershaded. This makes it harder to distinguish their form while they are swimming. |
| Breeding starts just as the Antarctic winter does: penguins arrive at their breeding grounds on the sea ice in early to mid-April | Penguins arrive at breeding grounds on sea-ice in early-mid April at the onset of the Antarctic winter. (note: 'penguins arrive', not 'pairs arrive': AAD describes pairs forming or re-forming at the colony) |
| Females lay a single egg in late April or May and pass it to their mate almost immediately | Females lay a single egg in late April or May and pass the egg off to their mate almost immediately. |
| travel about 50 to 120 kilometers back to open water to feed | Females then travel approximately 50 to 120km back to the ocean to find food. |
| called a brood pouch, low on the belly | Males incubate and protect eggs in their brood pouches, a specialized skin fold on their lower abdomens. |
| Chicks hatch in mid-July | Chicks hatch in mid-July, weighing about 315 grams. (note: hatch weight cut: ADW's 315 g and AAD's 150 to 200 g disagree) |
| Their mother's return can come before hatching or as much as a month after it | Depending on how far mothers have to travel for food, their return may be before the chicks hatch or up to a month thereafter. (note: 'as much as a month after it' = 'up to a month thereafter') |
| the father feeds them a nutrient-rich, milky substance he produces in his own esophagus until she is back | Males feed hatchlings by producing a nutrient-rich, milky substance in their esophagus until females return. |
| Antarctic wind chills down to minus 60 | Winter temperatures there range from -40 to 0°C, with wind chills reaching -60°C. |
| Antarctic silverfish, Nototheniidae fish, Antarctic krill, and glacial squid | the Antarctic silverfish (Pleuragramma antarcticum) is one of the most frequently consumed species. Fish from the family Nototheniidae are also consumed as a staple of their diet. Molluscs such as the glacial squid (Psychroteuthis glacialis) ... and the Antarctic krill (Euphausia superba) are also eaten regularly. |
| Antarctic coastal sea ice, pack ice, and the surrounding Southern Ocean | During their breeding season, emperor penguins congregate on dense stable ice attached to the coastline of Antarctica. ... Outside of breeding season, they spend most of their time in seasonally-packed ice zones, where open sea is easily available for foraging. |
| A rough, spiky-textured tongue helps them catch and eat slippery prey. | Emperor penguins have a rough and spiky-textured tongue, which helps them catch and eat slippery fish and squids more easily. |
| Wild emperors typically live 15 to 20 years | lifespan expectancy in the wild of 15 to 20 years |

## Meir & Ponganis (2009). High-affinity hemoglobin and blood oxygen saturation in diving emperor penguins. Journal of Experimental Biology.

https://doi.org/10.1242/jeb.033761

| The page says | The source says |
| :--- | :--- |
| can dive deeper than 500 meters and stay under for more than 23 minutes | diving to depths greater than 500 m and for durations longer than 23 min (note: 'deeper than' paraphrases 'greater than' for a depth figure; same meaning, no added strength) |
| One reason is their hemoglobin, the protein that carries oxygen in blood, which holds onto oxygen unusually tightly, like that of high-altitude birds and other penguins | To examine mechanisms underlying the exceptional diving ability of this species ... This investigation revealed enhanced Hb-O2 affinity (P50=28 mmHg, pH 7.5) in the emperor penguin, similar to high-altitude birds and other penguin species (note: 'one reason' rests on the study framing the affinity as a mechanism underlying diving ability; 'unusually tightly' glosses 'enhanced'; the source's own comparison now names other penguins too, so the trait is not presented as unique) |
| That lets a diving penguin carry more oxygen when blood oxygen runs low and use up more of the oxygen it breathed in before the dive | This allows for increased O2 at low blood PO2 levels during diving and more complete depletion of the respiratory O2 store. (note: 'the oxygen it breathed in before the dive' glosses 'the respiratory O2 store') |
| The blood in its arteries stays almost fully saturated with oxygen through much of a dive, and only drops significantly on the final climb to the surface | arterial SO2 levels are maintained near 100% throughout much of the dive, not decreasing significantly until the final ascent phase (note: scoped to arterial blood: the same abstract says venous blood O2 was nearly completely depleted in longer dives. 'almost fully' = 'near 100%'; 'only drops significantly on the final climb' = 'not decreasing significantly until the final ascent phase') |
| dives past 500 meters | diving to depths greater than 500 m |
| Dives deeper than 500 meters and longer than 23 minutes, with hemoglobin that grips oxygen unusually tightly | diving to depths greater than 500 m and for durations longer than 23 min ... enhanced Hb-O2 affinity (note: two facts side by side: the saturation profile was not measured on 500 m dives, so the old 'keeping blood almost fully saturated through dives deeper than 500 meters' was cut) |
| Emperor penguins can dive to depths greater than 500 meters and stay under for more than 23 minutes. | diving to depths greater than 500 m and for durations longer than 23 min |
| Their hemoglobin, the protein that carries oxygen in blood, holds onto oxygen unusually tightly, like that of high-altitude birds and other penguins, and the blood in their arteries stays almost fully saturated with oxygen through much of a dive. | enhanced Hb-O2 affinity (P50=28 mmHg, pH 7.5) in the emperor penguin, similar to high-altitude birds and other penguin species ... arterial SO2 levels are maintained near 100% throughout much of the dive (note: the two facts are joined by 'and', not 'which keeps': the abstract does not say the affinity causes the saturation profile) |

## Ponganis et al. (2003). Regional heterothermy and conservation of core temperature in emperor penguins diving under sea ice. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology.

https://doi.org/10.1016/s1095-6433(03)00133-8

| The page says | The source says |
| :--- | :--- |
| A diving penguin's wings run cold | grand mean temperatures in the wing vein, foot vein and lumbar subcutaneous tissue during dives were 7.6+/-0.7 degrees C (n=157 dives in three birds) ... the observed decreases in limb, anterior abdomen, subcutaneous and sub-feather temperatures |
| In a study of emperors diving from an isolated hole in the sea ice | Temperatures were recorded at several body sites in emperor penguins (Aptenodytes forsteri) diving at an isolated dive hole (note: 'sea ice' is the paper's own title: 'Regional heterothermy and conservation of core temperature in emperor penguins diving under sea ice') |
| the average temperature inside a wing vein during dives was about 7.6 degrees Celsius | grand mean temperatures in the wing vein, foot vein and lumbar subcutaneous tissue during dives were 7.6+/-0.7 degrees C (n=157 dives in three birds) |
| while the stomach averaged 37.1 and the chest muscle 37.8 | Grand mean temperatures (+/-S.E.) in central body sites during dives were: stomach: 37.1+/-0.2 degrees C (n=101 dives in five birds), pectoral muscle: 37.8+/-0.1 degrees C (n=71 dives in three birds) |
| Those readings fit a warm core and a cooled outer shell, caused by narrowed blood vessels near the body's surface (peripheral vasoconstriction), feathers that insulate less during a dive, and heat lost to the water | Such high temperatures within the body and the observed decreases in limb, anterior abdomen, subcutaneous and sub-feather temperatures are consistent with preservation of core temperature and cooling of an outer body shell secondary to peripheral vasoconstriction, decreased insulation of the feather layer, and conductive/convective heat loss to the water environment during the diving of these emperor penguins. (note: 'fit' = 'are consistent with'; 'caused by' = 'secondary to'; all three of the source's causes are named, not vasoconstriction alone) |

## Emperor penguin breeding cycle. Australian Antarctic Program.

https://www.antarctica.gov.au/about-antarctica/animals/penguins/emperor-penguin/breeding-cycle/

| The page says | The source says |
| :--- | :--- |
| around hatching time, adults weigh 22 to 30 kilograms | The chicks are very small when they hatch weighing only about 150 g to 200 g (adult penguins weigh 22 kg to 30 kg at this time of year). (note: replaces ADW's '25 to 45 kg as adults', whose low end the AAD figure and Robin et al.'s 18 kg leanest males both contradict) |
| before their yearly molt they have to almost double their body mass | tend to go out to sea at this time to start fattening up for their annual moult ... Adults have to almost double their body mass before the moult. |
| Males hold the egg on top of their feet inside a fold of warm skin called a brood pouch, low on the belly, for roughly 65 to 75 days until it hatches | gives the egg to her partner who carefully puts it on his feet and covers it with a skin fold. In this way the egg is kept toasty warm ... It takes 65 to 75 days for the eggs to hatch (note: 'until it hatches' restates 'for the eggs to hatch' as a duration. 'bare' was cut: neither AAD nor ADW says it) |
| months of fasting | It takes 65 to 75 days for the eggs to hatch - by the time the chicks appear, their fathers have fasted for 4 months! (note: 'appear' is the source's word for hatching, not a hedge on the fast) |
| A male holds the single egg on top of his feet inside a warm fold of skin called a brood pouch | eventually the female produces a single egg ... carefully puts it on his feet and covers it with a skin fold. In this way the egg is kept toasty warm ... they fit comfortably in the brood pouch |
| for roughly 65 to 75 days until it hatches, fasting the entire time and living entirely off body fat he laid down over the summer | The males cannot go out and feed with the egg on their feet. It takes 65 to 75 days for the eggs to hatch ... The males rely entirely on the body fat that they laid down during summer to survive the long winter fast. (note: 'until it hatches' restates 'for the eggs to hatch' as a duration) |
| By the time the female returns, he has lost nearly half his body mass | When the females finally return to the colony in July the males have lost nearly half their body mass and look quite skinny. |
| During winter storms, males huddle closely together to keep warm. | the males stay behind to incubate the eggs. During the winter storms they huddle closely together to keep warm. (note: replaces an ADW description under an FAQ whose ref is AAD) |
| for a bird whose male stands with the egg on his feet for 65 to 75 days, unable to leave it to feed | carefully puts it on his feet and covers it with a skin fold. ... The males cannot go out and feed with the egg on their feet. It takes 65 to 75 days for the eggs to hatch (note: vibe.reason, settle #173: replaces "awe-inspiring Antarctic endurance", a place and a mood; the music description is unchanged) |

## Emperor penguins. Australian Antarctic Program.

https://www.antarctica.gov.au/about-antarctica/animals/penguins/emperor-penguins/

| The page says | The source says |
| :--- | :--- |
| though some pass 40 | Some emperors live to more than 40 years but most do not live that long in the wild |

## Robin et al. (1988). Protein and lipid utilization during long-term fasting in emperor penguins. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology.

https://doi.org/10.1152/ajpregu.1988.254.1.r61

| The page says | The source says |
| :--- | :--- |
| Across the four-month winter fast, a male starts at about 38 kilograms, and the leanest are down to an estimated 18 by the time they head back to sea to feed | The body mass of male emperor penguins is approximately 38 kg at the beginning of the 4-mo winter fast connected with breeding, and it is an estimated approximately 18 kg in leanest birds at time of spontaneous refeeding. (note: restores 'estimated' and 'leanest birds'; the end point is refeeding, not hatching, and the fast starts at arrival, not pairing (AAD: 'since they arrived at the colony')) |

## Gilbert et al. (2006). Huddling behavior in emperor penguins: Dynamics of huddling. Physiology & Behavior.

https://doi.org/10.1016/j.physbeh.2006.04.024

| The page says | The source says |
| :--- | :--- |
| To save energy through the fast, males pack into huddles | Although huddling was shown to be the key by which emperor penguins (Aptenodytes forsteri) save energy and sustain their breeding fast during the Antarctic winter ... Throughout the breeding season, males huddled for 38+/-18% (S.D.) of their time |
| huddles that can hold hundreds of birds at densities of up to 10 per square meter | These huddles, formed during courtship and incubation in the colony, can be made up of more than hundreds of individuals, reaching densities of up to 10 birds per m 2 (note: 'more than hundreds' is a lower bound, so the page says 'hundreds', not 'several hundred') |
| the male alone incubates the egg | Both mates starve for about 45 days during the pairing period, while males alone take on the task of incubation, which adds another 65 days to their fast |

## Aptenodytes forsteri. The IUCN Red List of Threatened Species 2020: e.T22697752A157658053.

https://doi.org/10.2305/iucn.uk.2020-3.rlts.t22697752a157658053.en

| The page says | The source says |
| :--- | :--- |
| Near Threatened | IUCN Red List category: Near Threatened (NT). |
| The emperor penguin is listed as Near Threatened on the IUCN Red List. | IUCN Red List category: Near Threatened (NT). |