blue whale vs Common Pill Woodlouse

Balaenoptera musculus compared with Armadillidium vulgare

Key Differences

• blue whale is Vulnerable while Common Pill Woodlouse is Near Threatened.

Taxonomic Classification

Rank	blue whale	Common Pill Woodlouse
Kingdom same	Animalia (สัตว์)	Animalia (สัตว์)
Phylum	Chordata (สัตว์มีแกนสันหลัง)	Arthropoda (สัตว์ขาปล้อง)
Class	Mammalia (สัตว์เลี้ยงลูกด้วยน้ำนม)	Malacostraca (Crustaceans)
Order	Cetacea (Whales & Dolphins)	Isopoda (ไอโซพอด)
Family	Balaenopteridae (Rorquals)	Armadillidiidae
Genus	Balaenoptera (Rorquals)	Armadillidium
Species	Balaenoptera musculus	Armadillidium vulgare

Evolutionary Relationship

blue whale and Common Pill Woodlouse share a common ancestor at the Kingdom level: Animalia. (สัตว์)

Conservation Status

blue whale

VU — Vulnerable

Population: ~15.0K

Trend: Increasing ↑

Common Pill Woodlouse

NT — Near Threatened

Physical Characteristics

Attribute	blue whale	Common Pill Woodlouse
Diet	Carnivore	—
Average Lifespan	90 years	—
Average Length	30.0 m	—
Average Weight	150.0 t	—

Habitat & Geographic Range

blue whale

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 11 distinct biome types. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Asia (Taiwan), Europe (4 countries), and South America (Colombia, Ecuador). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its 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.

blue whale

The largest animal ever known to have lived on Earth, blue whales can reach 33 meters and 200 tonnes — their hearts alone weigh as much as a small car. Found in all oceans, they migrate between polar feeding grounds and tropical breeding areas. Filter feeders consuming up to 4 tonnes of krill daily. Endangered, with global populations estimated at 10,000–25,000 after near-extinction from 20th-century whaling.

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.

Shared Countries

Both species can be found in 4 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇵🇹 Portugal 🇸🇪 Sweden