Chocolate arion vs Long-tailed Sylph

Arion rufus compared with Aglaiocercus kingii

Key Differences

• Chocolate arion is Vulnerable while Long-tailed Sylph is Least Concern.

Taxonomic Classification

Rank	Chocolate arion	Long-tailed Sylph
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Chordata (Chordates)
Class	Gastropoda (Gastropoda)	Aves (Birds)
Order	Stylommatophora (Stylommatophora)	Apodiformes (Apodiformes)
Family	Arionidae	Trochilidae
Genus	Arion	Aglaiocercus
Species	Arion rufus	Aglaiocercus kingii

Evolutionary Relationship

Chocolate arion and Long-tailed Sylph share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Chocolate arion

VU — Vulnerable

Long-tailed Sylph

LC — Least Concern

Physical Characteristics

Attribute	Chocolate arion	Long-tailed Sylph
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Chocolate arion

Habitat

Inhabits temperate broadleaf and mixed forests and Mediterranean forests and woodlands within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found across Europe (7 countries) and North America (United States). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Long-tailed Sylph

Habitat

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

Range

Distributed across Colombia, Ecuador, Norway, and Venezuela.

Chocolate arion

The Chocolate Arion (Arion rufus), also known as the Large Red Slug or Chocolate Slug, is one of Europe's largest terrestrial slugs, with adults reaching up to 15 centimetres in length. It belongs to the family Arionidae within the phylum Mollusca, and despite its common name, adults display highly variable colouration ranging from reddish-orange to dark brown and nearly black — only certain colour morphs exhibit the chocolate-brown hue that partly inspired the name. Arion rufus is native to western and central Europe, where it inhabits woodland, hedgerows, gardens, agricultural land, and other moist habitats. It is also established as an introduced species in parts of North America. Like other arionid slugs, it is primarily a detritivore and herbivore, consuming dead plant material, fungi, living plant tissue, and sometimes carrion. It shelters under logs, stones, and leaf litter during dry or cold conditions, becoming active — particularly at night — during warm, moist weather. Chocolate arion can cause significant damage to gardens and crops. Reproduction is hermaphroditic; slugs exchange sperm and lay batches of translucent eggs in soil or under debris. The IUCN classifies this species as Vulnerable, reflecting pressures on native European populations from habitat change and, possibly, competition and hybridisation with related Arion species.

Long-tailed Sylph

One of the most strikingly ornamented hummingbirds, male long-tailed sylphs have iridescent green plumage and dramatically elongated, ribbon-like outer tail feathers reaching up to 22 cm — over three times the body length. Found in Andean cloud forests of Colombia and Venezuela, they inhabit humid montane forest between 1,400–2,800 meters elevation. Males perform elaborate display flights to attract females. Their extravagant tails are a classic example of sexual selection via female preference.

Shared Countries

Both species can be found in 1 countries:

🇳🇴 Norway