NL·0494Herbarium of the Nature Library
- Name
- Hypsibius exemplaris
- Family
- Hypsibiidae
- Native to
- Described in 2018 from a long-running laboratory culture originating in the UK; tardigrades as a group occur worldwide
- Habitat
- Freshwater ponds, Moss and sediment
Water bear (tardigrade)
Hypsibius exemplaris
Also calledBärtierchen (German) · Oso de agua (Spanish) · Shuǐxióng chóng 水熊虫 (Chinese) · Kumamushi (Japanese)
A plump, eight-legged micro-animal about a quarter of a millimetre long and the main laboratory model for studying tardigrades. Like many tardigrades it can survive drying out and freezing by shutting its body down almost entirely.
Hypsibius dujardini sensu lato is a species complex of tardigrade in the class Eutardigrada. A member of this complex, Hypsibius exemplaris, is widely used for various research projects pertaining to evolutionary biology and astrobiology. The species was described by Louis Michel François Doyère in 1840. Wikipedia
What it can do
- iSurvives slow drying by curling into a 'tun' and entering cryptobiosis, with metabolism nearly stopped
- iiTolerates freezing and recovers when thawed
- iiiProtects its cells while drying with tardigrade-specific disordered proteins that form a glassy state
- ivReproduces without males (parthenogenesis), so one animal can found a whole culture
In the field
Field marks
- aMicroscopic, ~0.2–0.3 mm
- bBarrel-shaped body with eight stubby legs
- cClaws on each leg
- dTransparent body
- Not to be confused with
- Other tardigrades need microscopy to identify.
Life & habits
- Diet
- Algae such as Chlorococcum, sucked from cells through a stylet-armed mouth
- Habitat
- Freshwater sediment and aquatic plants
- Size
- ~0.2–0.3 mm
- Lifespan
- A few weeks to a few months when active
It lumbers on eight stubby clawed legs and moults its cuticle as it grows, often laying eggs in the shed skin.
Where it lives
Recorded sightings
—
geo-referenced records in GBIF, from museums, herbaria and field observers.
Native range
Described in 2018 from a long-running laboratory culture originating in the UK; tardigrades as a group occur worldwide
Drag the globe to turn it. Dots are where records exist, not a range map; darker means more records.
In the stacks
Searching the stacks…
Every page naming Hypsibius exemplaris in the Biodiversity Heritage Library →
Marginalia
The pastor Johann Goeze named tardigrades 'kleiner Wasserbär' (little water bear) in 1773, and Lazzaro Spallanzani gave them the name tardigrado, 'slow stepper', in 1776 after reviving them from dust. This species was long misidentified as Hypsibius dujardini until it was described in 2018.
Curiosity
Its genome, sequenced in the 2010s, sparked debate over claims that tardigrades had borrowed large amounts of foreign DNA; later analyses found that most of it was contamination.
Photographs: iNaturalist contributors under the licences shown. Records: GBIF.org. Historical plates: Source Library (CC BY-SA 4.0; originals public domain). Summary text: Nature Library editors and Wikipedia (CC BY-SA). Medicinal and edibility notes are historical and educational, not advice.