Common Pill Woodlouse vs Emperor Penguin

Armadillidium vulgare compared with Aptenodytes forsteri

Taxonomic Classification

Rank	Common Pill Woodlouse	Emperor Penguin
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Arthropoda (Arthropods)	Chordata (Chordates)
Class	Malacostraca (Crustaceans)	Aves (Birds)
Order	Isopoda (Isopoda)	Sphenisciformes (Penguins)
Family	Armadillidiidae	Spheniscidae (Penguins)
Genus	Armadillidium	Aptenodytes (Great Penguins)
Species	Armadillidium vulgare	Aptenodytes forsteri

Evolutionary Relationship

Common Pill Woodlouse and Emperor Penguin share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Common Pill Woodlouse

NT — Near Threatened

Emperor Penguin

NT — Near Threatened

Population: ~595.0K

Trend: Stable →

Physical Characteristics

Attribute	Common Pill Woodlouse	Emperor Penguin
Diet	—	Carnivore
Average Lifespan	—	20 years
Average Length	—	1.1 m
Average Weight	—	40.0 kg

Habitat & Geographic Range

Common Pill Woodlouse

Habitat

Typically found in marine, freshwater, and terrestrial environments.

Range

Widely distributed across Africa (South Africa), Asia (Japan), Europe (6 countries), and North America (United States). Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

Emperor Penguin

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found in Norway. Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

Common Pill Woodlouse

<em>Armadillidium vulgare</em>, the common pill woodlouse, is a terrestrial isopod crustacean in the family Armadillidiidae, widely recognised for its ability to roll into a tight sphere when disturbed, a defensive behaviour that gives it the common name "pill bug" or "roly-poly." Unlike most crustaceans, it is fully adapted to life on land, breathing through modified gill-like structures that must remain moist. The species inhabits a broad range of environments, typically occurring under rocks, leaf litter, decaying wood, and in gardens and agricultural land, where it feeds on decomposing organic matter, playing an important role in nutrient cycling. <em>Armadillidium vulgare</em> is distributed across Europe, parts of Asia including Japan, South Africa, and North America including the United States, reflecting its success as a cosmopolitan species often transported inadvertently by human activity. It is assessed as Near Threatened on the IUCN Red List. Biological traits such as average lifespan, precise body dimensions, and detailed dietary composition across its range remain poorly documented in the scientific literature. Females brood their young in a marsupium, and the species is capable of parthenogenesis under certain conditions, contributing to reproductive flexibility.

Emperor Penguin

The world's largest penguin, emperor penguins stand up to 1.2 meters and weigh 45 kg, inhabiting the Antarctic continent in some of the most extreme conditions on Earth. They breed in midwinter darkness at temperatures below -60°C, with males incubating single eggs on their feet under a brood pouch for 65 days while females are at sea. Their huddling behavior — cycling individuals through the warm center of thousands-strong groups — is a masterclass in cooperative survival.

Shared Countries

Both species can be found in 1 countries:

🇳🇴 Norway