Common Pipistrelle Bats Research Articles

Effect of Fungi Presence on Wing Morphometry and Flight Behaviour in the Common Pipistrelle Bats (Pipistrellus pipistrellus)

Effect of Fungi Presence on Wing Morphometry and Flight Behaviour in the Common Pipistrelle Bats (Pipistrellus pipistrellus)

Temporal mismatches in flight activity patterns between Pipistrellus kuhlii and Prays oleae in olive farms: Implications for biocontrol services potential

Abstract Biocontrol services are widely recognized to provide key incentives for bat conservation. However, we have virtually no information on whether and how disruptions in bat‐mediated biocontrol services are driven by mismatches between the temporal activity patterns of insectivorous bats and insect pests. We investigated the temporal relationship between the nightly activity patterns of the common pipistrelle bat (Pipistrellus kuhlii) and the olive fruit moth (Prays oleae). Temporal mismatches between species pairs were estimated as the time difference (expressed as a percentage of the night) at which P. kuhlii and P. oleae reached 50% of their abundance. The study was carried out during spring, summer, and fall between 2017 and 2019 in 60 olive farms representing increasing levels of structural simplification (as a surrogate of agricultural intensification). Olive farms were classified as exhibiting high (i.e. HIGH olive farms; n = 27), intermediate (MID; n = 18), and low (LOW; n = 15) structural complexity. Temporal mismatches between the activity levels of P. kuhlii and P. oleae varied between seasons and types of olive farms, being comparatively lower in summer than in spring and fall. Furthermore, summer was the only season in which temporal mismatches between species pairs differed between types of olive farms, with higher temporal mismatches found in LOW than in HIGH and MID olive farms. Overall, our work demonstrates the existence of temporal mismatches between the nightly activity patterns of P. kuhlii and P. oleae. Furthermore, it demonstrates that the structural simplification of olive farms increases temporal mismatches between species pairs, particularly in summer when bat‐mediated biocontrol services are most needed. Synthesis and applications. Future research should consider mismatches between the temporal activity patterns of insectivorous bats and insect pests. Otherwise, the actual impact of agricultural intensification on bat‐mediated biocontrol services as well as the economic impact of their loss on the agriculture industry might be underestimated. To enhance biocontrol services, we propose increasing the availability of suitable roosting and foraging sites as well as conserving areas of remnant native woodland and scattered hollow‐bearing trees.

Bats (Chiroptera) of the Ujście Warty National Park and the surrounding area

Bat research was carried out in 2012-2013 in the Ujście Warty National Park and in adjacent areas. Bats were caught in chiropterological nets, searched for in winter and summer roosts. Detector listening was carried out and the owls' diet was analyzed for the presence of bats among their prey. In the national park area, 11 species of bats were detected, and together with the Natura 2000 area "Ujście Warty" and the neighbouring areas, a total of 15 species were detected: the Daubenton's bat Myotis daubentonii, Natterer's bat Myotis nattereri, Brandt's bat Myotis brandtii, noctule bat Nyctalus noctula, serotine bat Eptesicus serotinus, common pipistrelle bat Pipistrellus pipistrellus, soprano pipistrelle bat Pipistrellus pygmaeus, Nathusius' pipistrelle bat Pipistrellus nathusii, brown long-eared bat Plecotus auritus, gray long-eared bat Plecotus austriacus, western barbastelle bat Barbastella barbastellus, greater mouse-eared bat Myotis myotis, Bechstein's bat Myotis bechsteinii, pond bat Myotis dasycneme and the parti-coloured bat Vespertilio murinus. The bat fauna of this area is relatively rich compared to other protected areas and presented results constitute an important supplement to the knowledge about the vertebrate fauna of the national park and its vicinity.

First case of Ehrlichia canis infection in the common pipistrelle bat (Pipistrellus pipistrellus)

AbstractThe present case report investigates the infection of a common pipistrelle bat (Pipistrellus pipistrellus) with various vector‐borne bacteria in northern Tunisia. The examined bat was found to be infested with the rat flea Xenopsylla cheopis and the specific bat mites Macronyssus spp. Spleen, liver and heart samples and ectoparasites were tested by polymerase chain reaction (PCR) assays targeting major vector‐borne bacteria. Only DNA of Anaplasmataceae bacteria was detected in spleen, liver and flea samples. Phylogenetic analysis of the 16S rRNA sequence obtained in this study suggested that this bat was infected with a specific Ehrlichia canis strain previously detected in domestic and wild canids and their associated ticks. We reported here the first case of infection with Ehrlichia canis in a bat. Hence, further studies must be undertaken to elucidate the potential role of bats in the epidemiology of this vector‐borne bacteria.

Видове різноманіття кажанів (Chiroptera) в Українському Приазов’ї та особливості їхнього перебування за сезонами

The article presents the results of regional surveys of bats in 2010–2020 in places planned for the construction of wind farms. With the use of modern ultrasonic detectors, computer programs and an electronic library of voices, 15 species were found in the Ukrainian Azov Region. Their highest diversity (11–13 species) was revealed in places of intensive migration. First of all, these are the sites Armyansk, Chaplynka, and Askania-Nova, which are located between the Dnieper valley and the Crimean Peninsula. Probably, in this area, bats migrating from the northern and north-eastern regions cross the land and join those moving along the Azov coast. The movement of a significant number of animals is noticeable in the west of the Molochna River. A relatively large variety of bats occurs near the sites Botiyevo, Orlivka, and Primorsk, located directly on the northern shore of the Sea of Azov, along which the migratory movements of bats are particularly strong. During winter, with limited research in this period, 8 species were found, whereas 13 species during spring and autumn migrations and 11 species in summer. The almost complete transformation of the steppe into agrocoenoses bordered by forest belts and irrigation canals undoubtedly affected bats in addition to global warming. In recent years, in all places of the Ukrainian Azov Region, there has been a decline in the number of the common pipistrelle (Pipistrellus pipistrellus) and serotine bats (Eptesicus serotinus), and an increase in the abundance of the noctule bat (Nyctalus noctula), Kuhl's pipistrelle (Pipistrellus kuhlii), Nathusius' pipistrelle (Pipistrellus nathusii), and parti-coloured bat (Vespertilio murinus). In all seasons, the least common species were the brown long-eared bat (Plecotus auritus), Daubenton's bat (Myotis daubentonii), greater noctule (Nyctalus lasiopterus), lesser noctule (Nyctalus leisleri), Savi's pipistrelle (Hypsugo savii), and western barbastelle (Barbastella barbastellus).

Sex and Age Variation in the Phenology of a Common Pipistrelle Bat (Pipistrellus pipistrellus) Population in Front of a Hibernaculum

The annual life cycle of temperate bats is typically accompanied by seasonal movements. In autumn, individuals of several species display very active flying behaviour around preferred locations, often hibernacula, a behaviour called swarming. This behaviour is usually characterized by a strong male-biased sex ratio and is often considered to be related to mating. Alternatively, these groupings may be a social behaviour related to the location and quality assessment of hibernacula and may enable this information to be transferred to juveniles, the maternal guidance hypothesis. Our study reports the results of a weekly survey of a bat community in an abandoned mine in Switzerland from April to October 2009, a period longer than the swarming period. The site is characterized by numerous visiting species as well as a high number of common pipistrelle bats displaying autumnal swarming like behaviour at the entrance of the mines. Thirteen species were present at the site with a total of 1,589 individuals of which 1,404 (88%) were common pipistrelle bats allowing us to focus on intersexual and age variations in their arrival phenology. Although the recapture rate was too low to obtain a reliable population size estimator, our data suggest that the site attracts individuals from a large area, possibly from several different nursing colonies and therefore requires a national conservation status. Adult males were present at the site throughout the study period with a peak from mid-July to the end of August. Females arrived later and both sexes displayed a swarming like behaviour in July and August. During this period, the sex ratio was slightly female biased, an unexpected pattern when compared with other swarming species. The absence of a male-biased sex ratio suggests that swarming behaviour in pipistrelle bats may have functions other than mating. Juveniles of both sexes joined the site about two weeks later suggesting that the maternal guidance hypothesis also did not explain this phenology pattern. The number of days between recaptures was greater for males than females indicating that males stay longer or return more often to the sites than females. Further studies may bring insights to the understanding of the function of swarming in pipistrelle bats.

High frequency social calls indicate food source defense in foraging Common pipistrelle bats

Social calls have the function to coordinate the behavior of animals. In the presence of conspecifics foraging Common pipistrelle bats (P. pipistrellus) emitted, in addition to typical echolocation signals, two types of social calls: complex social calls and an as-of-yet undescribed, short, frequency-modulated call type with high terminal frequency, which we term “high frequency social call”. By recording the flight and acoustic behavior of free flying pairs of foraging P. pipistrellus with an array of four microphones we were able to determine their three-dimensional flight paths and attribute emitted calls to particular behavioral situations. Complex social calls were emitted at further inter-individual distances and at large bearing angles to conspecifics, whereas high frequency social calls were produced at significantly shorter distances and at smaller bearing angles. These calls were associated with chasings and the eviction of the intruder. We assume that the emission of both types of social calls by foraging bats reflects a two-stage-process of the occupation and defense of a food patch. Common pipistrelle bats use complex social calls to claim a food patch and switch to agonistic behaviors, including chasings and high frequency social call emissions, when they defend their foraging territory against an intruder.

Genome sequence of an aichivirus detected in a common pipistrelle bat (Pipistrellus pipistrellus).

The family Picornaviridae includes important human and animal pathogens that are associated with a wide range of diseases and, in some cases, have zoonotic potential. During epidemiological surveillance of bats, we identified, by next-generation sequencing (NGS) techniques, the presence of picornavirus RNA in a common pipistrelle bat (Pipistrellus pipistrellus). By coupling NGS, primer-walking strategies, and sequence-independent protocols to obtain the sequences of the 5' and 3' termini, we reconstructed the genome sequence of picornavirus strain ITA/2017/189/18-155. The genome of the bat picornavirus is 8.2kb in length and encodes a polyprotein of 2462 amino acids. A comparison of polyprotein sequences revealed that this virus is distantly related (65.1% and 70.9% sequence identity at the nucleotide and amino acid level, respectively) to a bat aichivirus identified in 2010. Phylogenetic analysis showed that this picornavirus clustered closely with members of the genus Kobuvirus, which also includes human and animal aichiviruses. The identification of aichiviruses in several animal hosts is providing hints that will lead to an understanding of their origin and evolutionary patterns.

Measuring the effect of wing tears on flight in common pipistrelle bats (Pipistrellus pipistrellus)

Bat wings are susceptible to tearing. Many bats are admitted to care with wing tears and their flight is subjectively measured prior to release. This study presents a new method to objectively measure the effect of bat wing tears on the flight of common pipistrelle bats, Pipistrellus pipistrellus. Bats were filmed and their wing movements and body positions tracked using freely available software. Results found that bats with bilateral tears moved their wings with smaller movements, and with more wing beats per second. Bats with wing tears tended to tilt their whole body towards the healthier wing – which is the wing with no or smaller wing tears. Differences in wing movements and body positioning suggest that flight might be affected in bats with wing tears, and future work should assess whether foraging and survival are also affected in these animals.

Hibernation of bats in post-Soviet military objects in Poland

In the years 2004-2018, data on bats wintering in 9 sites of the Northern Group of the Soviet Army (PGWAR) stationed in the years 1945-1993 in Poland were obtained. A total of at least 11 bat species were found: greater mouse-eared bat Myotis myotis, Natterer’s bat M. nattereri, Daubenton’s bat M. daubentonii, Bechstein’s bat M. bechsteinii, whiskered/Brandt’s/Alcathoe bats M. mystacinus/brandtii/alcathoe, brown long-eared bat Plecotus auritus, grey long-eared bat P. austriacus, western barbastelle Barbastella barbastellus, serotine bat Eptesicus serotinus, common noctule Nyctalus noctula, common pipistrelle Pipistrellus pipistrellus and bats determined to the genus Pipistrellus. From 6 to 449 individuals hibernated in the facilities. Noteworthy is the presence of three species from Annex II of the Habitats Directive of EU. In most of the facilities, M. myotis and B. barbastellus were found, and M. bechsteinii in Wilkocin only. Wintering sites were used by numerous bats and also by endangered species therefore those buildings should be advisable to be covered with forms of nature protection.

Optimized biological tools: ultrastructure of rodent and bat teeth compared to human teeth

Enamel, the outer layer of the teeth of vertebrates, is the hardest tissue in their body. In general, enamel is highly mineralized and has a special ultrastructure that directs the mechanical properties of teeth and thereby their biological functions. However, there are differences between the enamel ultrastructures of different species. The authors compare the teeth of the Eurasian beaver Castor fiber, the African mole rat Fukomys kafuensis and the common pipistrelle bat Pipistrellus pipistrellus by high-resolution analytical methods, including scanning electron microscopy, quantitative wavelength-dispersive X-ray spectroscopy and X-ray powder diffraction. The enamel of all animals consists of long, thin and differently oriented calcium phosphate crystallites (length > 1 µm; thickness about 50 nm). On the outer surface of the beaver tooth, a thin layer of brown iron oxide was found. The diameter of the dentin tubuli was between 1 and 3 µm for all species – that is, comparable to that for human teeth.

Species-Specific Colocalization of Middle East Respiratory Syndrome Coronavirus Attachment and Entry Receptors.

Middle East respiratory syndrome coronavirus (MERS-CoV) uses the S1B domain of its spike protein to bind to dipeptidyl peptidase 4 (DPP4), its functional receptor, and its S1A domain to bind to sialic acids. The tissue localization of DPP4 in humans, bats, camelids, pigs, and rabbits generally correlates with MERS-CoV tropism, highlighting the role of DPP4 in virus pathogenesis and transmission. However, MERS-CoV S1A does not indiscriminately bind to all α2,3-sialic acids, and the species-specific binding and tissue distribution of these sialic acids in different MERS-CoV-susceptible species have not been investigated. We established a novel method to detect these sialic acids on tissue sections of various organs of different susceptible species by using nanoparticles displaying multivalent MERS-CoV S1A We found that the nanoparticles specifically bound to the nasal epithelial cells of dromedary camels, type II pneumocytes in human lungs, and the intestinal epithelial cells of common pipistrelle bats. Desialylation by neuraminidase abolished nanoparticle binding and significantly reduced MERS-CoV infection in primary susceptible cells. In contrast, S1A nanoparticles did not bind to the intestinal epithelium of serotine bats and frugivorous bat species, nor did they bind to the nasal epithelium of pigs and rabbits. Both pigs and rabbits have been shown to shed less infectious virus than dromedary camels and do not transmit the virus via either contact or airborne routes. Our results depict species-specific colocalization of MERS-CoV entry and attachment receptors, which may be relevant in the transmission and pathogenesis of MERS-CoV.IMPORTANCE MERS-CoV uses the S1B domain of its spike protein to attach to its host receptor, dipeptidyl peptidase 4 (DPP4). The tissue localization of DPP4 has been mapped in different susceptible species. On the other hand, the S1A domain, the N-terminal domain of this spike protein, preferentially binds to several glycotopes of α2,3-sialic acids, the attachment factor of MERS-CoV. Here we show, using a novel method, that the S1A domain specifically binds to the nasal epithelium of dromedary camels, alveolar epithelium of humans, and intestinal epithelium of common pipistrelle bats. In contrast, it does not bind to the nasal epithelium of pigs or rabbits, nor does it bind to the intestinal epithelium of serotine bats and frugivorous bat species. This finding supports the importance of the S1A domain in MERS-CoV infection and tropism, suggests its role in transmission, and highlights its potential use as a component of novel vaccine candidates.

Babesia vesperuginis in Common Pipistrelle ( Pipistrellus pipistrellus) and the Bat Soft Tick Argas vespertilionis in the People's Republic of China.

Babesia vesperuginis was molecularly detected in 10% (5/48) of common pipistrelle bats ( Pipistrellus pipistrellus) in Shihezi City, Northwestern China. Interestingly, four bat ticks ( Argas vespertilionis), from Babesia DNA-positive common pipistrelle bats, were also positive for B. vesperuginis. Our findings extend the geographic range of the common pipistrelle bat as a reservoir of B. vesperuginis in Asia.

The Recently Discovered Bokeloh Bat Lyssavirus: Insights Into Its Genetic Heterogeneity and Spatial Distribution in Europe and the Population Genetics of Its Primary Host.

In 2010, a novel lyssavirus named Bokeloh bat lyssavirus (BBLV) was isolated from a Natterer's bat (Myotis nattereri) in Germany. Two further viruses were isolated in the same country and in France in recent years, all from the same bat species and all found in moribund or dead bats. Here we report the description and the full-length genome sequence of five additional BBLV isolates from Germany (n=4) and France (n=1). Interestingly, all of them were isolated from the Natterer's bat, except one from Germany, which was found in a common Pipistrelle bat (Pipistrellus pipistrellus), a widespread and abundant bat species in Europe. The latter represents the first case of transmission of BBLV to another bat species. Phylogenetic analysis clearly demonstrated the presence of two different lineages among this lyssavirus species: lineages A and B. The spatial distribution of these two lineages remains puzzling, as both of them comprised isolates from France and Germany; although clustering of isolates was observed on a regional scale, especially in Germany. Phylogenetic analysis based on the mitochondrial cytochrome b (CYTB) gene from positive Natterer's bat did not suggest a circulation of the respective BBLV sublineages in specific Natterer's bat subspecies, as all of them were shown to belong to the M. nattereri sensu stricto clade/subspecies and were closely related (German and French positive bats). At the bat host level, we demonstrated that the distribution of BBLV at the late stage of the disease seems large and massive, as viral RNA was detected in many different organs.

Diversity and Morphometry of Chiropteran Fauna in Jahangirnagar University Campus, Savar, Dhaka, Bangladesh

The study was conducted to know the diversity of Chiropterans as well as their status and morphometric measurements in Jahangirnagar University campus between July, 2014 and April, 2015. Eight species of bats from three families were identified where Common Pipistrelle (Pipistrellus pipistrellus) and Pouch Tomb Bat (Saccolaimus saccolaimus) were recorded for the first time in Bangladesh. A total of 31bat individuals of 8 species were captured during 15 netting nights for morphological studies. Skull preparation was carried out for taking cranial measurements to identify the Pipistrelle species. No roosting colony of Pteropus gigantius was found in the study area but it visits the area only for foraging while the other species roost permanently. The old buildings in the study area provide suitable habitats for a significant number of insectivore bats. Indian Flying Fox (Pteropus gigantius) was the largest (mean head body length 23.33±1.86cm) and Least Pipistrelle (Pipistrellus tenuis) was the smallest (mean head body length 39.45±1.66 mm) species observed from the study area.Bangladesh J. Zool. 43(2): 201-212, 2015

Novel Cryptosporidium bat genotypes III and IV in bats from the USA and Czech Republic.

Bats from the families Rhinolophidae (n = 90) and Vespertilionidae (n = 191) in the USA and Czech Republic were screened for the presence of Cryptosporidium by microscopic and molecular analysis of faecal samples collected from rectum of dissected animals and from the ground beneath roosting sites. Cryptosporidium oocysts were not detected in any of the 281 faecal specimens examined using the aniline-carbol-methyl violet staining method. Nested PCR amplification, sequencing and phylogenetic analysis of the small ribosomal subunit rRNA and actin genes were used to identify isolates and infer evolutionary relationships. Cryptosporidium parvum was identified in a western small-footed bat (Myotis ciliolabrum) from the USA and a common pipistrelle bats (Pipistrellus pipistrellus) from the Czech Republic. Two novel genotypes were identified and named Cryptosporidium bat genotype III and IV. Bat genotype III was found in two big brown bats (Eptesicus fuscus) from the USA. Bat genotype IV was detected in two common pipistrelle bats from the Czech Republic.

Barriers and benefits: implications of artificial night-lighting for the distribution of common bats in Britain and Ireland.

Artificial lighting is a particular problem for animals active at night. Approximately 69% of mammal species are nocturnal, and one-third of these are bats. Due to their extensive movements-both on a nightly basis to exploit ephemeral food supplies, and during migration between roosts-bats have an unusually high probability of encountering artificial light in the landscape. This paper reviews the impacts of lighting on bats and their prey, exploring the direct and indirect consequences of lighting intensity and spectral composition. In addition, new data from large-scale surveys involving more than 265 000 bat calls at more than 600 locations in two countries are presented, showing that prevalent street-lighting types are not generally linked with increased activity of common and widespread bat species. Such bats, which are important to ecosystem function, are generally considered 'light-attracted' and likely to benefit from the insect congregations that form at lights. Leisler's bat (Nyctalus leisleri) may be an exception, being more frequent in lit than dark transects. For common pipistrelle bats (Pipistrellus pipistrellus), lighting is negatively associated with their distribution on a landscape scale, but there may be local increases in habitats with good tree cover. Research is now needed on the impacts of sky glow and glare for bat navigation, and to explore the implications of lighting for habitat matrix permeability.

Histological and histochemical analysis of the gastrointestinal tract of the common pipistrelle bat (Pipistrellus pipistrellus)

Bats have a very high mass-specific energy demand due to small size and active flight. European bat species are mostly insectivorous and the morphology of the gastrointestinal (GI) tract should be adapted accordingly. This study investigated the general anatomy by histology and the function by analysing carbohydrate distribution in particular of the mucus of the GI tract of the insectivorous bat Pipistrellus pipistrellus. The GI tracts of three individuals were dissected, fixed in formaldehyde, and embedded in paraffin wax. The tissues and cells of the GI tract of P. pipistrellus were analysed by classical (acid alizarin blue, haematoxylin-eosin, and Masson Goldner Trichrome), histochemical (periodic acid-Schiff, Alcian blue at pH 2.5) and lectin histochemical (lectins WGA and HPA) staining procedures. The GI tract of P. pipistrellus is organised into the typical mammalian layers. The short, narrow, and thin-walled esophagus is simple with a folded stratified squamous epithelium without glands but mucous surface cells secreting neutral mucus. The stomach is globular shaped without specialisation. Mucous surface cells produced neutral mucus whereas neck and parietal cells secreted a mixture of neutral and acid mucus. Chief cell surface was positive for N-acetylglucosamine and the cytoplasm for N-acetylgalactosamine residues. The intestine lacked a caecum and appendix. The small intestine was divided into duodenum, jejunum-ileum and ileum-colon. The epithelium consisted of columnar enterocytes and goblet cells. The large intestine is short, only represented by the descending colon-rectum. It lacked villi and the mucosa had only crypts of Lieberkühn. Towards the colon-rectum, goblet cells produced mucus with N-acetylglucosamine residues increasing in acidity except in colon-rectum where acidity was highest in the base of crypts. Along the tube the surface of enterocytes was positive for N-acetylglucosamine and N-acetylgalactosamine. All over the mucus filling the lumen of the GI tract was positive for N-acetylglucosamine and increased in acidity in all parts except of the stomach.In conclusion, the simple GI tract showed an anatomical reduction of tissue enabling for a short retention time and a reduction of the load carried during flight: short GI tract, lack of lymphoid tissue, missing of glands in certain regions, and a distinct pattern of mucus distribution, indicating different physiological functions of these areas. The GI tract of P. pipistrellus was typical for an insectivorous species probably representing the ancestral condition.

Strong matrilineal structure in common pipistrelle bats (Pipistrellus pipistrellus) is associated with variability in echolocation calls

The ontogeny and heritability of echolocation, an important sense in echolocating bats, is still not completely understood. Intraspecific variation in echolocation calls can be high, although the importance of possible explanatory variables (e.g. age, sex, social groups) remains largely unknown. Echolocation pulse features may vary among maternity roosts and this can theoretically be caused either by intercolony genetic differences or by vocal dialects learned during ontogeny within a roost (or a combination of both). In the present study, we analyzed intraspecific variation in echolocation parameters in relation to genetic structure at bi-parentally inherited microsatellites and maternally inherited mitochondrial (mt)DNA in maternal colonies of Pipistrellus pipistrellus in Central Europe. We found that individual colonies differ significantly in mtDNA, whereas the structure on nuclear markers is almost absent. This suggests a typical temperate bat social structure pattern, with strong sex-biased dispersal (i.e. philopatric females and dispersing males) (up to 92% of males leave their birth place according to our results). However, we show for the first time that genetic differentiation among mtDNA matrilines is associated with significant intercolony echolocation parameter differences. Because the genetic component of echolocation is not likely to be encoded by mtDNA, the results support the hypothesis of maternal echolocation dialect transmission to offspring, and the role of learning in this process is discussed.

Scanning Behavior in Echolocating Common Pipistrelle Bats (Pipistrellus pipistrellus)

Echolocating bats construct an auditory world sequentially by analyzing successive pulse-echo pairs. Many other mammals rely upon a visual world, acquired by sequential foveal fixations connected by visual gaze saccades. We investigated the scanning behavior of bats and compared it to visual scanning. We assumed that each pulse-echo pair evaluation corresponds to a foveal fixation and that sonar beam movements between pulses can be seen as acoustic gaze saccades. We used a two-dimensional 16 microphone array to determine the sonar beam direction of succeeding pulses and to characterize the three dimensional scanning behavior in the common pipistrelle bat (Pipistrellus pipistrellus) flying in the field. We also used variations of signal amplitude of single microphone recordings as indicator for scanning behavior in open space. We analyzed 33 flight sequences containing more than 700 echolocation calls to determine bat positions, source levels, and beam aiming. When searching for prey and orienting in space, bats moved their sonar beam in all directions, often alternately back and forth. They also produced sequences with irregular or no scanning movements. When approaching the array, the scanning movements were much smaller and the beam was moved over the array in small steps. Differences in the scanning pattern at various recording sites indicated that the scanning behavior depended on the echolocation task that was being performed. The scanning angles varied over a wide range and were often larger than the maximum angle measurable by our array. We found that echolocating bats use a “saccade and fixate” strategy similar to vision. Through the use of scanning movements, bats are capable of finding and exploring targets in a wide search cone centered along flight direction.