Common Bladderwort vs common sea hare

Utricularia vulgaris compared with Aplysia punctata

Key Differences

• Common Bladderwort is Near Threatened while common sea hare is Least Concern.

Taxonomic Classification

Rank	Common Bladderwort	common sea hare
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Mollusca (Mollusks)
Class	Magnoliopsida (Dicots)	Gastropoda (Gastropoda)
Order	Lamiales (Lamiales)	Aplysiida (Aplysiida)
Family	Lentibulariaceae	Aplysiidae
Genus	Utricularia	Aplysia
Species	Utricularia vulgaris	Aplysia punctata

Conservation Status

Common Bladderwort

NT — Near Threatened

common sea hare

LC — Least Concern

Physical Characteristics

Attribute	Common Bladderwort	common sea hare
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Bladderwort

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Distributed across Belgium, Denmark, Norway, Sweden, and United States. Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

common sea hare

Habitat

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

Range

Distributed across Denmark, Norway, Portugal, and Sweden.

Common Bladderwort

The common bladderwort (<em>Utricularia vulgaris</em>) is a carnivorous aquatic plant belonging to the family Lentibulariaceae. It is classified as Near Threatened on the IUCN Red List, reflecting population declines linked to habitat loss and water quality degradation. The species has been recorded across diverse terrestrial tropical to temperate habitats in Belgium, Denmark, Norway, Sweden, and the United States. <em>Utricularia vulgaris</em> is typically found in slow-moving or still freshwater bodies such as ponds, lakes, ditches, and marshes. It is rootless and free-floating, with finely divided submerged stems bearing numerous small bladder-like traps that capture zooplankton, small aquatic invertebrates, and even mosquito larvae through a rapid suction mechanism. The plant produces yellow snapdragon-like flowers on emergent stems above the water surface during summer. Its carnivorous strategy allows it to supplement nutrients in nutrient-poor aquatic environments. Biological traits of this species remain poorly documented in the scientific literature.

common sea hare

<em>Aplysia punctata</em>, the common sea hare, is a large opisthobranch sea slug in the family Aplysiidae, order Aplysiida, found in the northeastern Atlantic Ocean and Mediterranean Sea, with confirmed records from Denmark, Norway, Portugal, and Sweden. This species typically inhabits shallow subtidal and intertidal zones with abundant macroalgae, feeding primarily on red and green algae — a diet that influences the color of the defensive purple ink it secretes when threatened. <em>Aplysia punctata</em> is a simultaneous hermaphrodite, capable of acting as both male and female during mating, and often forms mating chains involving multiple individuals. It can reach considerable size among European opisthobranch species, though body dimensions vary considerably with age and feeding conditions. The species is classified as Least Concern by the IUCN, reflecting stable populations across its coastal range. Biological traits for this species remain poorly documented in the scientific literature, including precise average data on lifespan, body length, weight, and detailed seasonal dietary patterns, though its general herbivorous feeding on macroalgae is well established.

Shared Countries

Both species can be found in 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden