Echolocating bats can use acoustic landmarks for spatial orientation

Jensen, Marianne; Moss, Cynthia F.; Surlykke, Annemarie

doi:10.1242/jeb.01901

Cited by 66 publications

(46 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They were most likely directed towards the landing grid behind the obstacle. A similar pattern was reported by Jensen et al (Jensen et al, 2005) and Surlykke et al (Surlykke et al, 2009).…”

Section: Echolocation Behavioursupporting

confidence: 90%

See 1 more Smart Citation

Echolocation behaviour of the big brown bat (Eptesicus fuscus) in an obstacle avoidance task of increasing difficulty

Sändig

Schnitzler

Denzinger

2014

Journal of Experimental Biology

View full text Add to dashboard Cite

Four big brown bats (Eptesicus fuscus) were challenged in an obstacle avoidance experiment to localize vertically stretched wires requiring progressively greater accuracy by diminishing the wire-towire distance from 50 to 10 cm. The performance of the bats decreased with decreasing gap size. The avoidance task became very difficult below a wire separation of 30 cm, which corresponds to the average wingspan of E. fuscus. Two of the bats were able to pass without collisions down to a gap size of 10 cm in some of the flights. The other two bats only managed to master gap sizes down to 20 and 30 cm, respectively. They also performed distinctly worse at all other gap sizes. With increasing difficulty of the task, the bats changed their flight and echolocation behaviour. Especially at gap sizes of 30 cm and below, flight paths increased in height and flight speed was reduced. In addition, the bats emitted approach signals that were arranged in groups. At all gap sizes, the largest numbers of pulses per group were observed in the last group before passing the obstacle. The more difficult the obstacle avoidance task, the more pulses there were in the groups and the shorter the within-group pulse intervals. In comparable situations, the better-performing bats always emitted groups with more pulses than the less well-performing individuals. We hypothesize that the accuracy of target localization increases with the number of pulses per group and that each group is processed as a package.

show abstract

“…They were most likely directed towards the landing grid behind the obstacle. A similar pattern was reported by Jensen et al (Jensen et al, 2005) and Surlykke et al (Surlykke et al, 2009).…”

Section: Echolocation Behavioursupporting

confidence: 90%

“…Sometimes the bats emitted an additional group, usually of two signals before passing the obstacle. These pulses were most likely directed to the landing grid behind the obstacle (Jensen et al, 2005;Surlykke et al, 2009). These signals do not belong to the terminal group and were not included into the statistical analysis.…”

Section: Data Recording and Analysismentioning

confidence: 99%

Echolocation behaviour of the big brown bat (Eptesicus fuscus) in an obstacle avoidance task of increasing difficulty

Sändig

Schnitzler

Denzinger

2014

Journal of Experimental Biology

View full text Add to dashboard Cite

show abstract

“…While informative, the results of small-scale landmark-use experiments in predatory species do not provide clear-cut answers to this question (e.g. Jensen et al, 2005;Mueller and Mueller, 1979;Schnitzler et al, 2003;Surlykke et al, 2009). In the present study, we concur with Stich and Winter's (Stich and Winter, 2006) dietspecific predictions and extend this hypothesis to bats other than phyllostomids.…”

Section: Introductionsupporting

confidence: 64%

Niche-specific cognitive strategies: object memory interferes with spatial memory in the predatory bat, Myotis nattereri

Hulgard

Ratcliffe

2014

Journal of Experimental Biology

View full text Add to dashboard Cite

Related species with different diets are predicted to rely on different cognitive strategies: those best suited for locating available and appropriate foods. Here we tested two predictions of the nichespecific cognitive strategies hypothesis in bats, which suggests that predatory species should rely more on object memory than on spatial memory for finding food and that the opposite is true of frugivorous and nectivorous species. Specifically, we predicted that: (1) predatory bats would readily learn to associate shapes with palatable prey and (2) once bats had made such associations, these would interfere with their subsequent learning of a spatial memory task. We trained freeflying Myotis nattereri to approach palatable and unpalatable insect prey suspended below polystyrene objects. Experimentally naïve bats learned to associate different objects with palatable and unpalatable prey but performed no better than chance in a subsequent spatial memory experiment. Because experimental sequence was predicted to be of consequence, we introduced a second group of bats first to the spatial memory experiment. These bats learned to associate prey position with palatability. Control trials indicated that bats made their decisions based on information acquired through echolocation. Previous studies have shown that bat species that eat mainly nectar and fruit rely heavily on spatial memory, reflecting the relative consistency of distribution of fruit and nectar compared with insects. Our results support the niche-specific cognitive strategies hypothesis and suggest that for gleaning and clutter-resistant aerial hawking bats, learning to associate shape with food interferes with subsequent spatial memory learning.

show abstract

“…Although bats can use spatial memory to reference the position of obstacles in a familiar flyway (17)(18)(19), we exclude the possibility that the silent bat oriented entirely by spatial memory in this study. It may be possible for a bat to use spatial memory instead of echolocation to avoid fixed obstacles; however, the unpredictable movement of a conspecific eliminated the possibility that the silent bat could rely on spatial memory to avoid in-flight collision.…”

Section: Discussionmentioning

confidence: 99%

Flying in silence: Echolocating bats cease vocalizing to avoid sonar jamming

Chiu

Xian

Moss

2008

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

116

105

View full text Add to dashboard Cite

Although it has been recognized that echolocating bats may experience jamming from the signals of conspecifics, research on this problem has focused exclusively on time-frequency adjustments in the emitted signals to minimize interference. Here, we report a surprising new strategy used by bats to avoid interference, namely silence. In a quantitative study of flight and vocal behavior of the big brown bat (Eptesicus fuscus), we discovered that the bat spends considerable time in silence when flying with conspecifics. Silent behavior, defined here as at least one bat in a pair ceasing vocalization for more than 0.2 s (200 ms), occurred as much as 76% of the time (mean of 40% across 7 pairs) when their separation was shorter than 1 m, but only 0.08% when a single bat flew alone. Spatial separation, heading direction, and similarity in call design of paired bats were related to the prevalence of this silent behavior. Our data suggest that the bat uses silence as a strategy to avoid interference from sonar vocalizations of its neighbor, while listening to conspecific-generated acoustic signals to guide orientation. Based on previous neurophysiological studies of the bat's auditory midbrain, we hypothesize that environmental sounds (including vocalizations produced by other bats) and active echolocation evoke neural activity in different populations of neurons. Our findings offer compelling evidence that the echolocating bat switches between active and passive sensing to cope with a complex acoustic environment, and these results hold broad implications for research on navigation and communication throughout the animal kingdom.echolocation ͉ jamming avoidance ͉ passive listening ͉ spatial hearing A ctive sensing enables a wide range of animal species to orient and forage under conditions where light levels are low or absent (1). Self-produced acoustic or electric signals give rise to information about the environment that is used to guide a variety of behaviors. Echolocating animals produce ultrasonic signals and determine the direction, distance, and features of objects in the environment from the arrival time, amplitude, and spectrum of sonar reflections (2). Electric fish generate discharges from an electric organ in the tail, and sense the location and features of nearby objects from amplitude and phase changes in the electric field (3).With the benefits of active sensing also come challenges, namely the potential for interference from signals produced by neighboring conspecifics. Past research has uncovered strategies by which echolocating bats and electric fish avoid jamming through active adjustments in the signals they produce to probe the environment. Wave-type weakly electric fish modify the electric organ discharge frequency, and pulse-type weakly electric fish change the timing of electric organ discharge to avoid interference from the signals of neighbors (3). In echolocating bats, spectral and/or temporal adjustments in the characteristics of sonar vocalizations, which yield acoustic separation between s...

show abstract

Echolocating bats can use acoustic landmarks for spatial orientation

Cited by 66 publications

References 41 publications

Echolocation behaviour of the big brown bat (Eptesicus fuscus) in an obstacle avoidance task of increasing difficulty

Echolocation behaviour of the big brown bat (Eptesicus fuscus) in an obstacle avoidance task of increasing difficulty

Niche-specific cognitive strategies: object memory interferes with spatial memory in the predatory bat, Myotis nattereri

Flying in silence: Echolocating bats cease vocalizing to avoid sonar jamming

Contact Info

Product

Resources

About