Emperor Penguin
The emperor penguin (Aptenodytes forsteri) is the largest penguin and the only one that breeds during the Antarctic winter.
The emperor penguin (Aptenodytes forsteri) is the largest penguin and the only one that breeds during the Antarctic winter. In April 2026 the IUCN moved it from Near Threatened to Endangered, because the loss of sea ice is projected to halve the population by the 2080s.
🧬 Field Guide Specimen: Open Emperor Penguin in the CRV Science Field Guide to log the specimen, see its place among the Reptilia lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.
Winter Breeding: How Do Males Keep the Egg Warm?
After the female lays one egg, the male balances it on his feet under a fold of skin for about two months, fasting through winter temperatures far below freezing. Males huddle together in large groups and rotate positions so that each gets time inside the warm center.
Diving Champion
Emperors dive to more than 500 meters and hold their breath for over 20 minutes, using hemoglobin and myoglobin with a high affinity for oxygen and slowing their heart rate to conserve it.
Sea Ice and Climate
Chicks need stable sea ice until they fledge. In 2022, ice broke up early in parts of the Bellingshausen Sea and nearly all chicks in several colonies drowned. Models project big declines if warming continues. See Climate change.
Emperor Penguin at a Glance
| Property | Value |
|---|---|
| Scientific name | Aptenodytes forsteri |
| Kingdom | Animalia |
| Phylum | Chordata |
| Class | Aves |
| Order | Sphenisciformes |
| Family | Spheniscidae |
| Field Guide group | Reptilia: Aves (Birds) |
| Diagnostic feature (Field Guide) | Solid heavy bones countering buoyancy, rigid wing flippers, countershaded insulation blubber. |
| IUCN Red List status | Endangered (EN), assessed 2026 |
| Dive depth | More than 500 meters |
See Also
- Climate change — sea ice loss
- Thermodynamics — heat conservation in huddles