The first Adélie penguin specimens were collected by crew members of French explorer Jules Dumont d'Urville on his expedition to Antarctica in the late 1830s and early 1840s.

Jacques Bernard Hombron and Honoré Jacquinot, two French surgeons who doubled as naturalists on the journey, described the bird for science in 1841, giving it the scientific name Catarrhactes adeliæ.

[7] Although it has no identifiable subspecies,[8] the Adélie penguin has two distinct genetic lineages: one found primarily in the Ross Sea, and the other widespread throughout the Antarctic.

[16] Once they have moulted a third time, 7–9 weeks after hatching, the immature birds are similar to adults in appearance, though they tend to be smaller with a bluer tinge to their upperparts and white (rather than black) chins and throats.

They will not nest on ice, and preferentially choose areas where wind or the angle of the sun (or both) helps to keep snow drifts from accumulating.

[20] At the start of the breeding seasons, colony sites may be up to 100 km (62 mi) from open water, though the distance decreases as summer progresses and the pack ice breaks up.

[23] Apsley Cherry-Garrard, a survivor of Robert Falcon Scott's ill-fated British Antarctic Expedition of 1910, documented details of penguin behaviour in his book The Worst Journey in the World.

"They are extraordinarily like children, these little people of the Antarctic world, either like children or like old men, full of their own importance..."[24] George Murray Levick, a Royal Navy surgeon-lieutenant and scientist who also accompanied Scott, commented on displays of selfishness among the penguins during his surveying in the Antarctic: "At the place where they most often went in [the water], a long terrace of ice about six feet in height ran for some hundreds of yards along the edge of the water, and here, just as on the sea-ice, crowds would stand near the brink.

When they had succeeded in pushing one of their number over, all would crane their necks over the edge, and when they saw the pioneer safe in the water, the rest followed."

The dogs became frantic with excitement as he neared them: he supposed it was a greeting, and the louder they barked and the more they strained at their ropes, the faster he bustled to meet them.

He was extremely angry with a man who went and saved him from a very sudden end, clinging to his trousers with his beak, and furiously beating his shins with his flippers.

It was not an uncommon sight to see a little Adélie penguin standing within a few inches of the nose of a dog which was almost frantic with desire and passion.

Despite the species difference between the Adélie and the emperors, the individual charged the petrel, then placed itself between the predator and the chicks until it retreated.

[35] Jellyfish including species in the genera Chrysaora and Cyanea were found to be actively sought-out food items, while they previously had been thought to be only accidentally ingested.

[37] Adélie penguins arrive at their breeding grounds in late October or November, after completing a migration that takes them away from the Antarctic continent for the dark, cold winter months.

With a reduction in sea ice, populations of the Adélie penguin have dropped by 65% over the past 25 years in the Antarctic Peninsula.

The observing researchers suggested that this was practice for heterosexual encounters or a "response to high sexual motivation but a lack of females."

Adélie penguins living in the Ross Sea region in Antarctica migrate an average of about 13,000 kilometres (8,100 mi) each year as they follow the sun from their breeding colonies to winter foraging grounds and back again.

[47] Adélie penguins are faced with extreme osmotic conditions, as their frozen habitats offer little fresh water.

Such desert conditions mean that the vast majority of the available water is highly saline, causing the diets of Adélie penguins to be heavy in salt.

[48] The amount of sodium imposed by this sort of diet is still relatively heavy and can create complications when considering the less tolerant chicks.

[48] Adélie penguins also manage their salt intake by concentrating cloacal fluids to a much higher degree than most other birds are capable.

This ability is present regardless of ontogeny in Adélie penguins, meaning that both adults and juveniles are capable of withstanding extreme levels of salt ion concentration.

In aquatic birds such as the Adelie penguin, nasal salt glands excrete an extremely concentrated sodium chloride solution, reducing the load on their kidneys.

The concentration of salts and nitrogenous wastes helps to facilitate the flow of material from the sea to the land, serving to make it habitable for bacteria which live in the soils.

[51] In 2024, researchers from Federation University Australia reported more than 532 dead Adélie penguins on Antarctica's Heroína Island, with the H5N1 bird flu suspected as the cause.

Samples from the deceased penguins are under analysis, and the H5 strain has been detected in local skua seabirds, potentially facilitating further spread.

[52] Because of its very large and increasing population (estimated at more than 10 million mature individuals in 2020), and its unfragmented habitat, the Adélie penguin is considered by the International Union for Conservation of Nature to be a species of least concern.

[2] A comprehensive census of the global Adélie penguin population was carried out in 2014 using analysis of high-resolution satellite images in combination with actual field surveys.