Big Finner vs Cimar Round Ray

Balaenoptera physalus compared with Urotrygon cimar

Key Differences

• Big Finner is Endangered while Cimar Round Ray is Near Threatened.

Taxonomic Classification

Rank	Big Finner	Cimar Round Ray
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Mammalia (Mammals)	Elasmobranchii
Order	Cetacea (Whales & Dolphins)	Myliobatiformes (Myliobatiformes)
Family	Balaenopteridae (Rorquals)	Urotrygonidae
Genus	Balaenoptera (Rorquals)	Urotrygon
Species	Balaenoptera physalus	Urotrygon cimar

Evolutionary Relationship

Big Finner and Cimar Round Ray share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Big Finner

EN — Endangered

Cimar Round Ray

NT — Near Threatened

Physical Characteristics

Attribute	Big Finner	Cimar Round Ray
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Big Finner

Habitat

Found across multiple habitat types including tropical and subtropical dry broadleaf forests, flooded grasslands and savannas, and montane grasslands and shrublands, among 4 distinct biome types within the Neotropic biogeographic realm.

Range

Widely distributed across Asia (Taiwan), Europe (5 countries), and South America (Colombia, Ecuador, Venezuela). Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Cimar Round Ray

Big Finner

Big Finner (Balaenoptera physalus) is classified as Endangered (EN) on the IUCN Red List. At high risk of extinction in the wild, with significant population decline and ongoing threats to survival.

Cimar Round Ray

The Cimar round ray (Urotrygon cimar) is a small stingray in the family Urotrygonidae, found in the eastern Pacific Ocean along the coasts of Central America and northern South America, including the waters of Costa Rica, Panama, Colombia, and Ecuador. It inhabits shallow coastal and estuarine waters over sandy and muddy bottoms, typically at depths of less than 50 meters, where it feeds on small benthic invertebrates and fish. Like other round rays in the genus Urotrygon, it has a nearly circular disc outline, a relatively slender tail, and a venomous caudal spine used defensively against predators. The species is classified as Near Threatened by the IUCN, reflecting its restricted range, vulnerability to coastal habitat degradation, and incidental capture in artisanal and commercial fisheries throughout its range. Bycatch in shrimp trawls and gill nets represents a significant ongoing threat to Urotrygon species throughout the eastern Pacific. Shallow coastal habitats in Central America and Colombia face continued pressure from development, mangrove loss, and pollution. The species' reproductive biology, like that of most Urotrygon rays, involves ovoviviparity, with females giving birth to live young after internal development. Population assessments for this species remain limited, and more data on abundance and mortality rates are needed.