Acoustic mirrors as sensory traps for bats

Sensory traps pose a considerable and often fatal risk for animals, leading them to misinterpret their environment. Bats predominantly rely on their echolocation system to forage, orientate, and navigate.We found that bats can mistake smooth, vertical surfaces as clear flight paths, repeatedly colliding with them, likely as a result of their acoustic mirror properties. The probability of collision is influenced by the number of echolocation calls and by the amount of time spent in front of the surface. The echolocation call analysis corroborates that bats perceive smooth, vertical surfaces as open flyways. Reporting on occurrences with different species in the wild, we argue that it is necessary to more closely monitor potentially dangerous locations with acoustic mirror properties (such as glass fronts) to assess the true frequency of fatalities around these sensory traps

Global warming alters sound transmission: Differential impact on the prey detection ability of echolocating bats

Climate change impacts the biogeography and phenology of plants and animals, yet the underlying mechanisms are little known. Here, we present a functional link between rising temperature and the prey detection ability of echolocating bats. The maximum distance for echo-based prey detection is physically determined by sound attenuation. Attenuation is more pronounced for high-frequency sound, such as echolocation, and is a nonlinear function of both call frequency and ambient temperature. Hence, the prey detection ability, and thus possibly the foraging efficiency, of echolocating bats and susceptible to rising temperatures through climate change. Using present-day climate data and projected temperature rises, we modelled this effect for the entire range of bat call frequencies and climate zones around the globe. We show that depending on call frequency, the prey detection volume of bats will either decrease or increase: species calling above a crossover frequency will lose and species emitting lower frequencies will gain prey detection volume, with crossover frequency and magnitude depending on the local climatic conditions. Within local species assemblages, this may cause a change in community composition. Global warming can thus directly affect the prey detection ability of individual bats and indirectly their interspecific interactions with competitors and prey

越中国 富山藩札 町御吟味所札 銭札 300文

日本銀行金融研究所所蔵藩札資料番号：ⅢAエドa1-38-2-18(1)科学研究費助成事業（研究成果公開促進費）で電子化を実施データベースの名称：藩札等に関する統合データベース課題番号：18HP8038藩札の利用に関するお問い合わせ：藩札画像の転載（出版物・HP等）に際しては、日本銀行貨幣博物館への申請手続きが必要です。詳しくは貨幣博物館ホームページ（http://www.imes.boj.or.jp/cm/service/）をご覧ください