Common Pondskater vs Polar bear

Gerris lacustris compared with Ursus maritimus

Key Differences

Common Pondskater is Least Concern while Polar bear is Vulnerable.

Taxonomic Classification

Rank	Common Pondskater	Polar bear
Kingdom same	Animalia (動物)	Animalia (動物)
Phylum	Arthropoda (節足動物)	Chordata (脊索動物)
Class	Insecta (昆虫)	Mammalia (哺乳類)
Order	Hemiptera (カメムシ目)	Carnivora (ネコ目)
Family	Gerridae	Ursidae (Bears)
Genus	Gerris	Ursus (Bears)
Species	Gerris lacustris	Ursus maritimus

Evolutionary Relationship

Common Pondskater and Polar bear share a common ancestor at the Kingdom level: Animalia. (動物)

表示 Kingdom: Animalia

Conservation Status

Common Pondskater

LC — Least Concern

Polar bear

VU — Vulnerable

Population: ~26.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	Common Pondskater	Polar bear
Diet	—	Carnivore
Average Lifespan	—	25 years
Average Length	—	2.4 m
Average Weight	—	450.0 kg

Habitat & Geographic Range

Common Pondskater

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Polar bear

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found in Norway. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Pondskater

<em>Gerris lacustris</em>, the common pondskater, is an aquatic insect in the family Gerridae, well known for its remarkable ability to walk and skate across the surface of still or slow-moving freshwater bodies using surface tension. Microscopic water-repellent hairs on its legs trap air and prevent the insect from breaking the water film, allowing it to detect vibrations from struggling prey and move rapidly across the water surface. The species is a predator and scavenger, typically feeding on small invertebrates, including other insects, that fall onto or become trapped at the water surface. <em>Gerris lacustris</em> is distributed across Europe, with confirmed records from Belgium, Denmark, Norway, and Sweden, and is among the most commonly encountered water striders in temperate European ponds, lakes, and slow-flowing rivers. It is assessed as Least Concern on the IUCN Red List, reflecting widespread abundance and absence of major conservation threats. The species overwinters as an adult in terrestrial habitats and returns to water in spring. Biological traits such as average adult lifespan, precise body dimensions, body mass, and detailed dietary composition remain poorly documented in the scientific literature. Adults are capable of flight and can colonise new water bodies effectively.

Polar bear

地球上で最大の陸上肉食動物であるホッキョクグマは700kgを超えることがあり、カナダからロシアまでの北極海氷域全体に分布する。ワモンアザラシとヒゲアザラシを狩るために海氷に依存する高度に特化した海洋哺乳類である。広大な距離を泳ぐことができる優れた泳者でもある。脆弱種に指定されており、気候変動による急激な北極海氷の消失で個体群が深刻な圧力を受けている。