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Globally, bats provide critical ecosystem services. Rabies, caused by rabies virus and related lyssaviruses, is one of the most significant zoonoses associated with bats. Bat biologists study bats in the laboratory and the field. To minimize the risk of disease, all bat handlers should be vaccinated against rabies and undergo routine serological testing to measure their rabies virus neutralizing antibody levels. They should use best practices to avoid exposures, such as personal protective equipment, especially gloves appropriate to the size of the bat(s) being handled. Attention to such details will prevent unnecessary exposures and avoid some of the accompanying negative perceptions that endanger bats on a global level. The small body sizes of many bats (<50 g, many <20 g) and small teeth makes their defensive bites easy to overlook. Breaks in the skin, however small, may result in exposure to lyssaviruses in the animals’ saliva. Exposure to blood-feeding bats is less common because these species are geographically restricted to the Neotropics and are the only species whose natural feeding behavior could involve transmission of rabies virus. Understanding viral transmission, preventing exposures, and responding appropriately to bites will minimize the consequences of this deadly zoonosis.

We present evidence that a relatively widespread and common bat from South East Asia comprises two morphologically cryptic but acoustically divergent species. A population of the bicoloured leaf–nosed bat (Hipposideros bicolor) from Peninsular Malaysia exhibits a bimodal distribution of echolocation call frequencies, with peaks in the frequency of maximum energy at ca. 131 and 142 kHz. The two phonic types are genetically distinct, with a cytochrome bsequence divergence of just under 7. We consider the mechanisms by which acoustic divergence in these species might arise. Differences in call frequency are not likely to effect resource partitioning by detectable prey size or functional range. However, ecological segregation may be achieved by differences in microhabitat use; the 131 kHz H. bicoloris characterized by significantly longer forearms, lower wing loading, a lower aspect ratio and a more rounded wingtip, features that are associated with greater manoeuvrability in flight that may enable it to forage in more cluttered environments relative to the 142 kHz phonic type. We suggest that acoustic divergence in these species is a consequence of social selection for a clear communication channel, which is mediated by the close link between the acoustic signal and receptor systems imposed by the highly specialized nature of the hipposiderid and rhinolophid echolocation system.

ABSTRACTKerivoula pellucidais a small (4.5 g) vespertilionid bat, which forages in the understorey of tropical rainforests in Southeast Asia. Most echolocation signals are characteristic for the subfamily (very high-frequency, broadband FM calls (sweeping down from 178 kHz to 58 kHz) of low intensity and short duration (< 3.0 ms)), but this species also produces stereotypical calls of a markedly different structure. The arrangement of signal elements in these calls is unusual, and we present here a detailed analysis of calls from thirteen adult individuals (nine males and four females). These multiharmonic calls are of much lower frequency (fundamental peak frequency of 36 kHz), higher intensity and longer duration (12.0 ms) than the orientation calls, and are composites comprising a long quasi-constant frequency (QCF) syllable followed by an upward frequency modulated sweep (UFM). From considerations of signal design and preliminary field observations, we consider possible functions of these calls.

Echolocation signal design in nine syntopic vespertilionid bats from the Malaysian rain forest understorey was studied. Four species of Kerivoula, two species of Phoniscus (Kerivoulinae) and three species of Murina (Murininae) all emitted calls that are typical of species that glean insects from surfaces: broadband, frequency-modulated (FM) calls of low intensity and short duration. However, calls were highly distinctive in the use of very large bandwidths (range: 89–123 kHz) and extremely high frequencies (start frequency 152–180 kHz; end frequency 43–86 kHz). Furthermore, calls were produced in groups of 2–15 at very high pulse repetition rates (37–105 Hz). The functional significance of these characteristics with respect to foraging strategy is discussed. Large signal bandwidths facilitate highly accurate target localization in terms of both range and angle estimation and can thus be interpreted as an adaptation to foraging in the highly cluttered environment of the forest understorey. The use of high frequencies so far in excess of those seen in other FM gleaning bats of the same size is less easily explained, but may represent a mechanism by which these species distinguish prey items using echolocation alone, without recourse to visual or auditory cues. Species exhibited differences in echolocation parameters, particularly the end frequency and the number of calls per group of calls. The two subfamilies differed from each other in multivariate space derived from echolocation parameters; calls of the Murininae were of lower frequency than the Kerivoulinae and were typically produced in smaller groups or singly. Within the subfamilies there was considerable overlap between species of Murina, but the Kerivoula spp. were clearly distinct from one another but not from the two Phoniscus spp.

The article highlights the face structure of several species of bats. The common vampire bat or Desmodus rotundus of Latin America was believed to have a blade-like appendage, triangular nose leaf, which was later discovered to be a soft, pliable one with heat sensors for locating blood-rich areas in the skin. The lesser naked bat or Cheiromeles parvidens are known for their characteristic smile and the absence of fur. The endangered banana bat of Mexico possesses the longest skull among all bat species, which it uses to take nectar from deep flowers.

We describe design of echolocation signals in 5 species of aerial-hawking insectivorous bats from Malaysia. These bats forage in open spaces above the forest or in large clearings and belong to 2 families: Molossidae (Chaerephon johorensis, Mops mops, Cheiromeles torquatus) and Vespertilionidae (Hesperoptenus blanfordi, Pipistrellus stenopterus). As is typical for aerial-hawking bats, all 5 species produced narrowband calls of long duration (6–21 ms) and low peak frequency (16–44 kHz). However, sequences recorded from bats flying at high altitude (>10 m) were characterized by an alternation between calls that differed in frequency of maximum energy (peak frequency), switching between high-and low-frequency calls. In some species, the types of calls also differed in duration and sound pressure level. We consider possible implications of the alternation of types of calls for the detection of prey in open spaces.