The Daubenton's is also called the 'fishing or water bat' due to its feeding method of gleaning insects stuck on the surface of water. It doesn't do this with its mouth but with its huge feet using them like grappling hooks.

A bat that is flying really close to the surface of a pond or slow moving river, looking like a little hovercraft, is very likely to be a Daubenton's bat. The wings hardly seem to be moving when they are feeding here. The bats fur is very neat and dark brown on the back. The underside is a very pale grey but never white. The face is bare and pink. Breeding condition females have a black chin spot.

Forearm 34 - 41mm / 2 inches
Length 45 - 55mm / 1¾ - 2¼ inches
Weight 7 - 12g / 3rd oz

Daubenton's bats are always found close to water although they do feed in wooded areas close by especially if their river is in flood. Roosts are usually in underground chambers that are humid. Roosts have been found that are under or in the walls of stone bridges that span rivers. Some roosts have been found in the expansion joints of modern bridges that go over rivers. Tree roosts have been known.

• Emergence: leaves roost quite late generally. It is common to observe pipistrelle bats foraging above a river and then 15 - 20 minutes later the Daubenton's move into the area, skimming the water. Compare emergence to other N. Irish bats.

• Flight: fast and agile; wing beat fast, sometimes even whirring. Hunts frequently 5-25 cm above the water. During flight over water the turns of this bat are very long. Natterer's bat in the same situation is much more agile, often 'flipping over' to change direction.

• Habitat: ponds, lakes, streams and also small brooks. Usually over relatively slow moving, calm water. Can also be found at the top of riparian tree lines. Although associated with water, Daubenton's bat can also be found for about a third of the time in other habitats. Occasionally this bat forages along a woodland path where it forages up and down the middle of the path. In comparison, the whiskered bat in the same situation will tend to 'hug' the edge of the vegetation more, without straying into the open. Generally this is true whenever Daubenton's bat is found near cluttered habitats. If foraging along a tree line it rarely flies within 2 m of the vegetation and when over water will avoid the overhanging trees and bushes near the edge of the water.

• Heterodyne:The loudest frequency of Daubenton's bats is 45kHz and is very rapid and regular. The best descriptions are grass burning or the purring of a cat. To tell the difference between these bats and '45 pips' turn the bat detector down to 35kHz. The Daubenton's can still be heard as rapid clicks. Pulse repetition rate is very fast and very regular compared with the irregular sound of the pipistrelle. It also has the most regular pulse repetition rate of the Myotis bats.
  

• Time expansion: Using time expansion bat detectors Daubenton's sound like day old chicks.
  Often, because the bat is foraging close to the water the call contains many 'missing' frequencies and also frequently ends with a bend. This may occur simply because of where the bat is feeding and may not be characteristic of Daubenton's bat. If other Myotis species carried out the same behaviour they may also produce a call with this shape. However, in most situations this bat seems to produce calls similar to this and it is only when it is flying in a very cluttered environment that the calls straighten out. Occasionally this bat produces calls that appear 'bent' at the top. The function of these calls is unknown. Other calls, which probably have a social function, have been recorded. See and hear time expanded call.