Overview
Daubenton’s Bat (Myotis daubentonii), celebrated across European natural history and folklore as the ‘Water Bat’, is an exceptionally agile, specialized, and biologically extraordinary vespertilionid bat native to the freshwater riverways, canals, and lakes of the Palearctic. Named in honor of the pioneering 18th-century French naturalist Louis-Jean-Marie Daubenton, this charismatic microchiropteran is world-famous for its unique, high-skill foraging niche: skimming across mirror-calm water surfaces at night like a miniature feathered hovercraft to harvest emerging aquatic insects.
Clad in dense, velvety greyish-brown to chocolate fur with a silvery-white underbelly and a pinkish-brown face, Myotis daubentonii is distinguished by its remarkably enlarged, muscular hind feet, which are bristling with stiff sensory hairs. Flying just five to twenty centimeters above the water’s surface, it uses an advanced biosonar tracking system to detect floating midges and caddisflies, dipping its colossal hairy feet into the surface tension like a set of biological landing gear to gaff prey directly out of the water. Flawlessly adapted to riparian ecosystems, Daubenton’s bat is an essential bioindicator of clean, healthy freshwater waterways.
AT A GLANCE
- Common Name: Daubenton’s Bat
- Scientific Name: Myotis daubentonii
- Category: Mammals
- Subcategory: Bats
- Size: Wingspan 24–27 cm (9.4–10.6 in); head-and-body length 45–55 mm (1.8–2.2 in); forearm length 35–42 mm (1.4–1.7 in)
- Weight: 7–12 g (0.25–0.42 oz)
- Lifespan: 15–20 years in the wild; maximum recorded longevity exceeds 28 years
- Diet: Specialized aquatic insectivore feeding on chironomid non-biting midges, caddisflies, mayflies, mosquitoes, and water boatmen
- Habitat: Riparian corridors, calm lowland rivers, canals, eutrophic lakes, forest ponds, and surrounding deciduous woodlands with bridge crevices and tree hollows
- Range: Widespread across the Palearctic realm, natively distributed from Ireland and Great Britain across continental Europe, Scandinavia, Russia, and Siberia eastward to the Sea of Okhotsk, Sakhalin, and Japan
- Conservation Status: Least Concern
Biology and Physical Characteristics
Morphologically, Myotis daubentonii represents an evolutionary marvel of aquatic surface trawling. Its most diagnostic physical adaptation is its hind limbs: the feet are disproportionately immense—measuring over half the length of the tibia—equipped with long, curved, needle-sharp claws and fringed with stiff, water-repellent bristles that slice through the water surface with minimal hydraulic drag. Its interfemoral tail membrane (uropatagium) is unusually broad and flexible, capable of scooping forward to form a deep pouch that catches insects scooped up by the feet. Its echolocation calls are broadband, frequency-modulated (FM) chirps sweeping from 85 down to 32 kilohertz, emitted at extremely high pulse repetition rates of up to one hundred pulses per second during terminal feeding buzzes to resolve minute ripples on the water surface. Its ears are medium-sized, rounded, and feature a straight, blunt tragus that extends half the length of the ear.
Behavior and Ecology
Behaviorally, Daubenton’s bats are strictly nocturnal, emerging from roosts roughly thirty minutes after sunset to travel along dark, tree-lined corridors directly to their aquatic hunting grounds. They hunt using two distinct tactics: ‘aerial hawking’ (snatching swarming midges just above the water) and ‘water trawling’ (skimming the feet along the water to snag floating pupae and emerging adult caddisflies). In summer, females form nursery maternity colonies of 20 to 100 individuals inside old stone bridge drain holes, tree hollows, or waterside masonry, where each female gives birth to a single pup in June or July, nursing it for three weeks until it learns to fly. In autumn, adults perform spectacular swarming rituals at the entrances of subterranean limestone caves, mines, and medieval fortifications, where thousands mate before entering deep winter hibernation from October to April at temperatures of 3°C to 8°C.
Conservation and Human Impact
Daubenton’s Bat is officially classified as Least Concern on the IUCN Red List of Threatened Species, supported by its immense circumboreal geographic distribution, high wild abundance, and stable or increasing populations across much of western and central Europe. The species has demonstrated remarkable adaptability, benefiting significantly from man-made canal networks, flooded gravel pits, and reservoir construction. However, localized populations are threatened by artificial light pollution along riverbanks (which disrupts dark commuting corridors), loss of riparian woodland roost trees, and water pollution that depletes benthic insect larvae. It is strictly protected under Annex IV of the EU Habitats Directive.
Interesting Factoid
Daubenton’s bat literally goes water skiing for dinner—it flies just two inches above the water and drags its giant hairy feet right through the lake surface like tiny fish hooks to snatch bugs trapped in the water film!