Rhinoceros auklet

It’s horn isn’t bone or keratin like a rhino’s horn—it’s actually a keratinized sheath that grows only during breeding season

Eric Ellingson


Rhinoceros auklet

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It’s horn isn’t bone or keratin like a rhino’s horn—it’s actually a keratinized sheath that grows only during breeding season

Population 1.3 Million

At first glance, it might look like just another puffin or auk with its stocky body, short wings, and dapper plumage, but a closer look reveals what sets it apart: a strange, horn-like projection that sprouts from the base of its bill during the breeding season. This fleshy “horn” is not permanent—it sheds once the breeding season ends—but while it lasts, it gives the bird an unmistakable rhinoceros-like profile, a feature unique among seabirds. Scientists believe this horn may function as a display signal, helping individuals recognize each other in crowded colonies or impress mates with their unusual ornamentation.

Like its puffin relatives, the Rhinoceros Auklet is a superb underwater hunter. It uses its wings as flippers to “fly” beneath the waves, chasing after small schooling fish like anchovies, sand lance, and herring. Unlike puffins, which usually carry a few fish crosswise in their bills, Rhinoceros Auklets are capable of cramming their bills full of dozens of fish at once, neatly lined up and sticking out at both ends of the beak like a feathered fisherman’s catch. This adaptation is particularly important during the breeding season, when adults make repeated fishing trips to feed their chicks.

One of the most charming quirks of the species is its nocturnal feeding behavior: instead of delivering food during the day, Rhinoceros Auklets wait until nightfall to return to their burrows, perhaps to avoid attracting gulls and other predators eager to steal their catch. For people lucky enough to watch colonies at dusk, the sight of dozens of these birds silently winging in against the darkening sky, bills stuffed with fish, is unforgettable.

Distribution

Country
Population est.
Status
Year
Comments
Canada
2018
Breeding
China
2018
Japan
2018
Korea
2018
Mexico
2018
North Korea
2018
Breeding
Russia
2018
Eastern Asian Russia
United States
2018
Breeding

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Terrestrial / Aquatic

Altricial / Precocial

Polygamous / Monogamous

Dimorphic (size) / Monomorphic

Active: Diurnal / Nocturnal

Social behavior: Solitary / Pack / Colony

Diet: Carnivore / Herbivore / Omnivore / Piscivorous / Insectivore

Migratory: Yes / No

Domesticated: Yes / No

Dangerous: Yes / No