Wintering Conditions and Heat Loss during Hibernation in the Brown Long-Eared Bat

Abstract

The aim of this study was to estimate heat loss in the brown long-eared bat during hibernation depending on the refugioclimate conditions. The measured values of refugioclimate parameters were: ambient temperature (Ta) 3–10 °C, relative humidity (Rh) 74–98% and air velocity (v) 0.06–0.95 m/s. Heat loss was calculated using convective heat transfer equations. Mean heat loss amounted to 4 W/m2. The results were compared to the heat loss calculated based on the fat burned during hibernation. Bats flying into underground systems during the hibernation period were captured and their body mass was measured. A loss of body mass of 2.6 g over the 126 days of hibernation was observed. Heat loss equalled 3.115 W/m2K.The presented method of calculating energy expenditure allows for non-invasive monitoring of the heat and fat losses of bats during hibernation. Such research may find application in designing artificial wintering sites.

Bat Hibernation: In Groups or Individually?

“…The purpose of hibernation is to minimize energy consumption during the unfavorable period of food shortage. Energy consumption is closely related to the refugioclimate of the bat habitat [15].…”

“…In this research, the authors limited the impact of the researcher's presence by minimizing the measurement time and taking measurements from the leeward side. To measure refugioclimate parameters (temperature (T), humidity (Rh), and air flow velocity (v)) SENSOTRON measuring instruments, modified and calibrated for the purposes of this study, were used with the following accuracy ratings [10,15]: The measurements were taken from the side of the incoming air using an extendable arm to prevent the observer from interfering with the readings [15].…”

“…In this research, the authors limited the impact of the researcher's presence by minimizing the measurement time and taking measurements from the leeward side. To measure refugioclimate parameters (temperature (T), humidity (Rh), and air flow velocity (v)) SENSOTRON measuring instruments, modified and calibrated for the purposes of this study, were used with the following accuracy ratings [10,15]: -Gas parameter meter-for humidity (Rh), range of 0-100%, resolution of indications 0.1% with an uncertainty of indications ±1.5%; for temperature (Ta), range of −50-200 °C, resolution of indications 0.1 °C with an uncertainty of ±0.1 °C; and for atmospheric pressure (p), range of 500-1500 hPa, resolution of indications 1 hPa with an uncertainty of ±2 hPa; -Thermo-anemometer (portable digital air speed (v) and temperature meter)-the measurement range was 0.01-20 m/s, with an uncertainty of indications ±0.01 m/s.…”

“…The measurements were taken from the side of the incoming air using an extendable arm to prevent the observer from interfering with the readings [15].…”

“…The purpose of hibernation is to minimize energy consumption during the unfavorable period of food shortage. Energy consumption is closely related to the refugioclimate of the bat habitat [15]. The metabolic changes in the state of energy equilibrium during hibernation depend on constant factors (species, size, weight, sex, and age of the individual) and variables (values of physical parameters of the environment).…”