common grey sea slug vs Common Murre

Aeolidia papillosa compared with Uria aalge

Key Differences

• common grey sea slug is Least Concern while Common Murre is Critically Endangered.

Taxonomic Classification

Rank	common grey sea slug	Common Murre
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Chordata (Chordates)
Class	Gastropoda (Gastropoda)	Aves (Birds)
Order	Nudibranchia (Nudibranchia)	Charadriiformes (Charadriiformes)
Family	Aeolidiidae	Alcidae
Genus	Aeolidia	Uria
Species	Aeolidia papillosa	Uria aalge

Evolutionary Relationship

common grey sea slug and Common Murre share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

common grey sea slug

LC — Least Concern

Common Murre

CR — Critically Endangered

Physical Characteristics

Attribute	common grey sea slug	Common Murre
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

common grey sea slug

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Belgium, Chile, Denmark, Norway, and Sweden.

Common Murre

Habitat

Typically found in various aerial, terrestrial, and aquatic environments.

Range

Distributed across Belgium, Denmark, Norway, Sweden, and United States. Currently classified as Critically Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

common grey sea slug

<em>Aeolidia papillosa</em>, commonly known as the common grey sea slug, is a nudibranch mollusc belonging to the genus Aeolidia within the family Aeolidiidae. Despite the species name referencing terrestrial and aquatic habitats including forests and freshwater, <em>Aeolidia papillosa</em> is primarily a marine organism. Its range includes Belgium, Chile, Denmark, Norway, and Sweden, indicating a distribution across the North Atlantic and into South American waters. Common grey sea slug is assessed as Least Concern on the IUCN Red List. The species is typically found in intertidal and subtidal zones, where it preys on sea anemones and stores stinging cells from its prey in its dorsal cerata for defense. Biological traits of this species remain poorly documented in the scientific literature.

Common Murre

<em>Uria aalge</em>, the common murre or common guillemot, is a seabird in the family Alcidae found across the North Atlantic and North Pacific Oceans. This colonial cliff-nesting bird typically breeds on rocky coastal ledges and sea stacks, often in dense aggregations that may number in the thousands. <em>Uria aalge</em> is a highly capable diver, using its wings to propel itself underwater in pursuit of fish, sand eels, and invertebrates. It is found in coastal and offshore marine waters during the non-breeding season, ranging across the northern seas. Recorded occurrence countries include Belgium, Denmark, Norway, Sweden, and the United States. Despite its wide distribution and historically large numbers, the common murre is currently assessed as Critically Endangered in certain regional contexts, with populations threatened by oil spills, bycatch in fishing nets, food web disruptions linked to climate change, and disturbance at breeding colonies. Biological traits such as lifespan, body size, and diet remain poorly documented at the population level for this species across its full range, though it is known to be a piscivore. The species is a key indicator of marine ecosystem health and a focus of ongoing seabird conservation efforts.

Shared Countries

Both species can be found in 4 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden