Download Mammal Research Institute Polish Academy of Sciences Ireneusz

Appendix 2 – Description of scientific achievements
Mammal Research Institute
Polish Academy of Sciences
Ireneusz Ruczyński
The role of senses, information transfer and cognitive skills
in roost finding by bats
Białowieża 2013
Name: Ireneusz Ruczyński
Date and place of birth: 9th January 1971, Nowe Miasto Lubawskie
Adress: Mammal Research Institute PAN, ul. Waszkiewicza 1, 17-230 Białowieża
Tel. +48 85 6827761, fax: +48 85 6812289; e-mail: [email protected]
Education and academic degrees
1. 2003: PhD; Museum and Institute of Zoology in Warsaw; dissertation title: “Factors
affecting selection and cavity use by bats in Białowieża Forest” (superwiser: Prof.
J.M. Wójcik)
2. 1995: Master of science; thesis: “Bats inhabiting man-made shelters in Zaborski and
Gostynińsko-Włocławski Lendscape Park” (superwiser: dr hab. Andrzej Przystalski)
3. 1990-1995: Nicolaus Copernicus University in Toruń, Faculty of Biology and Earth
Sciences
4. 1986-1990: General/Comprehensive Secondary School in Nowe Miasto Lubawskie
Scientific work
1. From 2004: Mammal Research Institute, Polish Academy of Sciences, „adiunkt” assistant professor
2. May 1998 - December 2003: Mammal Research Institute, Polish Academy of
Sciences, „asystent” – junior scientist
3. September 1997 – April 1998: Mammal Research Institute, Polish Academy of
Sciences, technical worker
SUMMARY OF PROFESSIONAL ACCOMPLISHMENTS
I was born in 1971 in Nowe Miasto Lubawskie. In 1995, I completed a degree in
Biology, Faculty of Biology and Earth Sciences, Nicolaus Copernicus University in Torun,
and got a master's degree in biology. In 1995-1997, I worked as a salesman of plastic
windows and stainless steel. This experience confirmed my decision of dedicating my life to
academic work. In the autumn of 1997, I started work at the Mammal Research Institute,
Polish Academy of Sciences (PAS), initially as a technician and, since May 1998, as a
researcher. In 2003, I defended my doctoral thesis “Factors affecting the selection and use of
shelters by bats in the Bialowieza Forest“ in the Museum and Institute of Zoology, Polish
Academy of Sciences in Warsaw and got a Ph.D. in biology. Since 2004, I have been working
in the Mammal Research Institute Polish Academy of Sciences as an assistant professor. In
2009-2011, I carried out the project "Cognitive processes in warm and cold” as a scholarship
holder in the Max Planck Institute in Seewiesen (Germany). The scholarship was financed by
the Polish Ministry of Science and Higher Education. I also received a four-month fellowship
funded by the Max Planck Institute in Seewiesen.
I am an author and co-author of 22 scientific papers, 17 of which were on the list of
the Journal Citation Reports. Some of these were published in highly ranked and prestigious
journals such as the Journal of Experimental Biology, Biology Letters, PLoS One or Forest
Ecology and Management. My studies have been cited 160 times in total. The Average
Citation Rate of my articles amounts to 9.41. The h-index (according to the Web of Science,
13th February 2013) came to 8, and the total summarized rate of IF for published articles
amounted to 27.6 (Appendix 3).
The results of my research have been presented at 24 national and international
conferences (e.g.in Australia, France, Germany and the Czech Republic). I have popularized
my scientific works in periodicals such as Academia, Sprawy Nauki PAN, Parki Narodowe,
Matecznik, and Puszczyk. I was also interviewed by Gazeta Wyborcza (the best selling Polish
journal) and Max Planck Research. The results were presented and discussed in Inside JEB
(Journal of Experimental Biology) and Current Biology.
Based on my scientific experience I have provided five expert opinions concerning
management plans for bat protection in Białowieża National Park, in Białowieża and
Hajnówka forest districts, and I have evaluated the impact of wind farms on the environment.
I am an experienced educator. In 2003-2010 (seven seasons), I was a lecturer at
"Summer Schools” - projects (BIOTER, BIOSEB) financed from EU sources and designed
for Master and PhD students from all over Europe. In the years 2008 -2009, I taught Forest
Zoology at the Bialystok University of Technology in Hajnówka. I also taught students of
primary and secondary schools, college students, tourist guides, workers of the Białowieża
National Park, etc. (about 50 hours). I have been a tutor of three master’s dissertations and a
supervisor of one master’s thesis, so far.
During my work I have also engaged myself in activities related to the organization of
science: I have reviewed articles for journals such as Functional Ecology, Ethology, Acta
Theriologica, Acta Chiropterologica, Folia Zoologica, Mammalia, etc (22 reviews, in total). I
reviewed grants for the Ministry of Science and Higher Education and the National Science
Centre, as well (5 reviews). I was a member of the Scientific Council of the Mammal
Research Institute (2007-2009), and Vice-chairman of the Local Ethics Committee in
Białystok (2007-2009).
I have developed my scientific experience in laboratories supervised by eminent
specialists such as Prof. P. Racey in Aberdeen University (Scotland), Prof. E. K.V. Kalko at
the University of Ulm (Germany), Dr. B.M. Siemers, Ph.D, of the Max Planck Institute in
Seewiesen (Germany) and Professor. B. Bogdanowicz from the Museum and Institute of
Zoology, Polish Academy of Sciences in Warsaw. Currently, I have been cooperating with
Prof. M. Wikelski, Dr. D. Dechmann and Dr. K. Safi from the Max Planck Institute in
Radolfzell (Germany).
My scientific interests focus on the ecology and behavioral ecology of animals. I am
particularly interested in sensory limitations in bats, and behavioral and cognitive adaptations
important for finding resources. I have used tree dwelling bats as a major model. During the
breeding season they use hollow trees - resources essential to the survival and growth of bats.
In my research I use a combination of field and experimental techniques (radio telemetry,
GIS, behavioral experiments, modeling).
As a student of Nicolaus Copernicus University in Toruń I began a study on the
relationship between the presence of bats in boxes, the structure of forest stands, and the
preferences in selecting boxes by bats [No. 5, in the publications from Appendix 3]. I also
studied the phenology of bat mortality in local fortifications [8]. I determined the relationship
between the ambient temperature and mortality of bats. The highest mortality was observed at
the highest ambient temperatures at the beginning, as well as at the end, of the hibernation
period. It indicated an increased risk of mortality during periods of intense physiological
processes (higher body temperature)
In 1997, I started work at the Mammal Research Institute PAS as a technician in the
project “The killing rate of ungulates by wolves in Białowieża Forest” in a team of Prof. W.
Jędrzejewski. The aim of this work was to study the influence of human activity, hunting of
prey by wolves, reproduction, and weather conditions on daily patterns and duration of
activity of radiotracked wolves (Canis lupus) in the Białowieża Forest [7]. Wolves were
active throughout the day, but their activity peaked at dawn and dusk, which coincided with
periods when they killed most prey. Periods of reproduction and high temperatures had less
pronounced effects on activity patterns. Human activity appeared to have no significant
influence on the temporal activity patterns of wolves.
In 1998, as soon as I became a staff researcher of the Mammal Research Institute PAS,
I began studying the ecology and behaviour of forest dwelling bats in Białowieża Forest. I
studied factors that determine the choice and use of shelters by bats of the genus Nyctalus (I
used radiotelemetry and field observations). The work was carried out in collaboration with
Prof. W. Bogdanowicz of the Museum and Institute of Zoology, Polish Academy of Sciences
in Warsaw. The study formed the basis of my dissertation and the results were published e.g.,
in the Journal of Mammalogy, Canadian Journal of Zoology and Forest Ecology and
Management etc. [9, 12, 14, 19, 22]. The studies have shown a very strong selection of roost
cavities. Bats chose both trees and hollows of specific location and size [9, 18]. Oaks and ash
trees were inhabited most frequently [12, 18]. Hollow sizes, and temperatures measured inside
the tree cavities indicated that bats would chose warm hollows [10], located high above the
ground and whose depth and size of entrance would reduce the risk of predation [9].
Significant differences were observed in the selection of roosting habitat between managed
and pristine areas of the forest [14]. Within the pristine forest, bats displayed a strong
preference for roost trees located in deciduous (oak-lime-hornbeam) stands, whereas in the
managed part of the forest, old wet woodland was preferred. The data revealed a possibility
of changes in selection of roosting habitat by bats [14]. I have shown that buildings located in
clearings of the Białowieża Forest are inhabited mainly by species which rarely use tree
cavities, and for which the access to old-growth forest is not a crucial factor. Also, the roof
leaning and size of buildings were most important factors for bats in site selection. Such
places provide a safe shelter and protection from extreme temperatures [11].
In cooperation with dr. J. Furmankiewicz, I carried out a field experiment in order to
test whether the social calls of the noctule bat (Nyctalus noctula), played from inside of the
trunk, are relevant for luring bats and for collecting information about their shelters. The
experiment showed that the bats eavesdrop on social calls and inspect the places where they
were generated [15]. These observations confirmed that eavesdropping can be an effective
mechanism of obtaining information from other bats, and that ‘spying’ can be an important
and simple mechanism for lowering individual costs of finding new cavities, as well as
maintaining group cohesion.
The high intelligence of bats, and their ease in learning observed during the
experiments, inspired me to start a research on the effects of changes in body temperature
(thus in the brain) on the process of learning and memorizing in bats [16]. Bats were trained
to find food in a simple maze and after finishing the training they hibernated. After short-term
hibernation the bats were able to find food in the maze properly [16]. It was shown that bats,
contrary to animals such as gophers, have physiological mechanisms that protect their spatial
memory. Consequently, I put forth the hypothesis that during hibernation, the memory is
protected mainly in long-lived animals (such as bats), which live in a complex environment.
Experiments testing the influence of torpor or its lack of influence on the memorizing skills of
bats showed no significant differences (publication in preparation). The results therefore show
that neither torpor nor hibernation significantly interfere with the process of memorising in
bats.
It is believed that animal cognitive skills are strictly related to the environment in
which the animals live, as well as to the selection pressure that promotes certain cognitive
abilities. Together with the team of B.M. Siemers, PhD, we therefore studied learning skills in
three bat species (genus Myotis) that differ in their hunting behavior and hunting habitat. We
compared learning rates for simple and difficult tasks and in relearning experiments. The
study found no difference in the rate of learning in simple tasks. Significant differences,
however, were observed among species in more complex tasks, as well as in an experiment in
which bats had to change their once trained behavior. Myotis cappacini – a species hunting by
the rivers in a less complex environment, needed the longest time of all in order to solve the
most complex tasks, and change once learned behaviors. The results suggest that the species
hunting in a complex, changing environment solve complex problems better and are more
flexible than others. (in review in PLoS One [33]).
In addition to research on the behavioral ecology of bats I have studied interspecific
competition in shrews (Prof. L. Rychlik’s team) and in flycatchers (Prof. W. Walankiewicz’s
team), as well as the accessibility of tree cavities for ‘cavity dwellers’ (including birds,
mammals, and bats). I have published articles on the use of radiotelemetry in studies of
shrews; on habitat selection in flycatchers; and a paper on habitat selection in flycatchers in
the Białowieża Forest [13, 17].
The results obtained during field research became a basis for designing experiments
with the object of examining behaviour and the role of social and non-social stimuli in the
selection of tree cavities [1, 2, 3]. These studies became part of my selected research
echivement and are presented below in detail.
SUMMARY OF PUBLICATIONS THAT MAKE UP SELECTED RESEARCH
ACHIEVEMENT
The role of senses, information transfer and cognitive skills in roost finding by bats
The selected research achievement consists of four articles [1, 2, 3, 4]. Three of these
[1, 2, 3] are experimental works. In laboratory conditions I analyzed the impact of sensory
stimuli (social and non social) on the rate of finding artificial cavities by three bat species. I
compared the interspecific differences in bat behavior occurring during searches for a tree
cavity, as well as the differences in the role of specific sensory stimuli in finding cavities [2].
In paper No. [3] I tested whether distinct visual stimuli may help in finding tree cavities. In
recent work [4] based on my own research and other available studies, I built an individualbased model (in collaboration with Dr. K. Barton) which explored the effectiveness of finding
roosts by bats with diverse sensory capabilities, and diverse tree discrimination skills in an
environment with varying availability of roost trees. I estimated the importance of information
transfer and the size of the colony for the effectiveness in finding hollow trees. The study was
the first known attempt to explore the problem of roost finding by forest dwelling bats in a
versatile and comprehensive manner. It took into account the environmental, sensory,
cognitive and social conditions.
Scientific problem
Most animals struggle with the problem of finding resources, such as food and shelter
that are limited and may be difficult to find. An efficient sensory system is extremely
important in this context, because it allows collection of information crucial for the detection
of suitable resources. However, there is a trade-off between the energetic cost of maintaining
a sensory structure encoding a particular sensory modality and the amount of reliable,
germane information obtained (Niven and Laughlin 2008). Consequently, possibilities for
improving the senses (such as increasing the range of detection) in the course of evolution are
limited, and selection pressures may favour other physiological, morphological or behavioural
adaptations. Animals can solve the problem of lack of precise information about the
environment by using compensatory plasticity (i.e. by improving the effectiveness of certain
sensors - when possible) or by behaving in a way that increases the chances of success - i.e.
selecting appropriate places or objects; memorizing the distribution of resources; transfering
the information to conspecifics (Hammer and Menzel 1995; Rauschecker 1995; Kimchi and
Terkel 2001). Althought such behaviours seem to be widespread, it is rarely studied in wild
animals. A particularly intriguing group of animals exposed to sensory limitations are bats.
They are nocturnal, fast fliers orientating in space by echolocation (Griffin 1958).
Echolocation, contrary to popular opinion, is not perfect, and bats are exposed to numerous
physical limitations in object detection (Schnitzler and Kalko 2001). Alimentary niche
segregation in bats is based on their echolocation capabilities, which is connected with
immense sensory specialization (Siemers and Schnitzler 2004). Slight frequency differences
in echolocation signals may determine the separation of ecological niches. In bats, these
differences play a similar role for niche segregation as bill length or thickness in Darwin's
finches. A number of limitations associated with echolocation force bats to use other senses as
well, such as vision. They also obtain information from other conspecifics, memorize the
location of resources, etc. (Gaudet and Fenton, 1984; Eklöf, Svensson et al. 2002; Dechmann,
Heucke et al . 2009; for example). The significance of senses other than echolocation in food
detection is relatively well studied, unlike the, for bats, equally important process of roost
detection. Because the vast majority of bat species are not able to build hides, they have to use
shelters (cavities), such as tree hollows, that are already present in the environment. Because
roosts are essential for the safety of animals and for the development of young, their selection
is very precise [8, 12]. During the breeding season, bats often change roosts (Lewis 1995).
They therefore need an effective strategy for finding them. Because they are long-lived, social
animals capable of learning, there are many potential mechanisms that reduce their costs in
finding roosts.
The aim of the published articles presented as a selected research achievement was to:
1. Determine the significance of the selected senses in the process of roost finding in bats
2. Determine the possible differences in rate and manner of roost finding in three species
of bats that differ in their echolocation adaptation and flying skills (ability of flying in
an environment with obstacles)
3. Determine the significance of social stimuli in the rate of roost finding
4. Build a theoretical model that would explore the effectiveness of roost finding by bats
that differ in their perception range and in their ability to discriminate trees with and
without cavities in environments with a diverse supply of hollow trees. The
importance of information transfer and colony size for the roost finding was estimated
as well.
RUCZYŃSKI I., Kalko E.K.V. and Siemers B.M. 2007. The sensory basis of roost finding in a
forest bat, Nyctalus noctula. Journal of Experimental Biology, 210: 3607-3615. [1]
As nocturnal animals, bats are exposed to difficulties in detecting obstacles, finding
food and roosts, etc. Although their echolocation ability allows them to detect objects in total
darkness, there are some physical limitations generated, among others, by the so-called
masking effect, which hinders some objects in the vicinity of the obstacles (like leaves,
stems). Vision, smell, and other senses are important in complementing the information about
the surrounding environment. The importance of particular senses in locating hollow trees –
recources vital for bats, had not yet been examined. In the study, I evaluated wether the visual
stimuli, as well as the stimuli related to the increase in temperature inside the hollow,
influence the efficacy of locating hollow trees by the noctule bat (Nyctalus noctula),
compared to situations where only echolocation was used. I also tested the influence of the
social stimuli (sound and smell) on the rate of finding hollow trees. In laboratory conditions I
played back sounds of bats and I placed bat odor samples in the cavities. I then compared the
rate of cavity detection. The social stimulus of echolocating sounds, played from inside of a
cavity, shortened the rate of cavity detection by noctule bats both in flight and when creeping
on the surface of the tree trunk. For the first time it had been experimentally proven that the
social stimuli may shorten the rate of cavity detection. Other stimuli provided during the
experiment had no significant influence on the rate of cavity finding.
The study showed that eavesdropping may be crucial in lowering the costs of cavity
detection by bats. (The article was cited 21 times; the paper was discussed in Current Biology,
Dispatch section)
RUCZYŃSKI I., Kalko E.K.V. and Siemers B.M. 2009. Calls in the forest: a comparative
approach to how bats find tree cavities. Ethology 115: 166-176. [2]
There is still scant knowledge of how bats search for and find new roosts; whether the
particular bat species differ in the rate of finding these, and wether the particular sensoric
stimuli are equally significant in the respective species. In this article I tested a hypothesis
assuming that the echolocation strategies and the flight agility are related to the methods and
rate of cavity detection and that they determine which stimuli are important in the process.
For the study I selected two bat species that varied in their echolocation strategies and flight
agility, i.e. Daubenton’s bat (Myotis daubentonii) and brown long-eared bat (Plecotus
auritus). The results were then compared to the results obtained in the noctule bat (Nyctalus
noctula). The noctule bat is a less agile species that hunts in open space, and its echolocation
is not adapted to detecting small objects located near obstacles. Daubenton’s bat is relatively
agile and hunts by the water. Brown long-eared bat is the most agile of all the studied species
- it can collect food off the leaves in flight. Its echolocation is adapted to moving in dense
environments (for example in the tree canopy). Among the selected bat species no significant
differences in the rate of cavity detection were observed. Brown long-eared bats would
mainly find hides in flight, while Dubenton’s bats and, to a higher degree, noctule bats, found
hides while creeping on the trunk surface. Comparison with noctule bats indicates that bat
agility may be a factor influencing the methods of cavity detection. Low agility species (in
particular noctule bats) spent more time creeping on the tree surface than in flight during
cavity searching.
The easiness with which both the noctule bat and the Daubenton’s bat move on the
tree surface suggests that the ‘quadruped’ way of moving is more important in insectivorous
species than is generally recognized. Visual and olfactory stimuli, as well as those related to
sensing the temperature (warming the cavity), did not accelerate the rate of cavity detection in
either Daubenton’s bats or brown long-eared bats. These data indicate that regardless of the
species and echolocation strategies, bats mainly tend to rely on echolocation.
The study also confirms that simple mechanisms of information transfer (based on
‘eavesdropping’) represent important strategy lowering the cost of cavity finding and
maintaining the social coherence in bat colonies.
RUCZYŃSKI I., Szarlik A. and Siemers B.M. 2011 Conspicuous visual cues can help bats to
find tree cavities. Acta Chiropterologica 13: 385-389. [3]
In nocturnal animals, vision may be an important sense allowing space orientation. In
bats, the role of vision in the process of finding various resources is rather poorly examined. It
is known, however, that with the use of sight, bats can obtain information crucial in space
orientation or food detection (Eklöf, Svensson et al. 2002; Holland, Borissov et al. 2010). My
research [1, 2] did not suggest that sight would significantly shorten the time of cavity
location. It was particularly surprising in the case of brown long-eared bats, a species that
uses sight in hunting (Eklöf and Jones 2003). I therefore designed an experiment in which
bats received stronger visual stimuli, i.e. I stripped bark around the cavity entrance (to
strengthen the contrast) and then compared the rate of detection in darkness and in
semidarkness. The results indicate that visual stimuli may be used to chose areas of cavity
detection and also that they shorten the time of detection. The results also indicates that bats,
while deciding on the area of cavity detection, may respond to many additional cues, such as
stripped bark, broken branches, the presence or lack of leaves, etc. In a broader context, the
research shows that crucial to chosing the area for cavity detecting is the process of learning
and associating the characteristics of trees with the occurance of cavities. Becausebats are
long-lived animals, they have more time for acquiring and verifying their detecting skills. In
other words, selection pressures may promote the development of complex learning skills.
RUCZYŃSKI I. and Bartoń K.A. 2012. Modelling sensory limitation: the role of tree selection,
memory and information transfer in bats' roost searching strategies. PLoS One 7(9): 1-11. [4]
The strategies of roost finding by bats are poorly recognized. Field and experimental
studies provide only a vague insight into the behavior of bats during detection of tree cavities
in natural conditions. I therefore decided that modeling is the best available tool for predicting
bat behavior (the optimal searching strategies of bats in nature). No theoretic model that
would indicate the behavior patterns of animals during the process of locating hides has been
established so far. Bats learn quickly [1, 2], memorize well, live in the colonies, and often use
tree hollows (their vital recources) as breeding sites. I therefore assumed that cavity detection
is a complex process, and that modelling requires taking the following factors into account:
the sensory limitations of bats, their ability to recognize and categorize trees (with and
without cavities), memorization of the distribution of trees, possibility of living in colonies,
collection of information from other individuals about occurring roosts, etc. Based on the
results of my own studies, as well as on available publications on cavity detection in bats I
worked with dr. K. Bartoń to designogether with dr K. Bartoń, we designed a theoretic model
to simulate bat behaviour during cavity detection, and determine the optimum behavior and
skills in the given conditions. The model simulated the rate of cavity detection in bats that
varied in their perception range (i.e. the distance from which bats were able to detect and
classify trees), and in their ability to discriminate trees in an environment with a different
proportion of trees with and without hollows. In addition, we simulated the effectiveness of
social calls transferring information about the occurrence of hollow trees in relation to the
number of bats in the modelled colony. The results of this modelling suggest that the key
factor for efficienct tree cavity detection is the ability for tree discrimination. This is
particularly important in situations when the risk of inspecting trees without cavities is high.
These data suggest that bats may be subject to a very strong selection in their learning ability,
and in associating the tree features with the presence of a hollow tree.
The studies did not find the perception range (distance from which the bats are able to
classify the tree), to be important for the effectiveness of finding cavities.This due to the fact
that bats can move very fast and the advantage of widening the range of correct tree
classification is insignificant.
Although the transfer of information between bats accelerates the rate of finding a
hollow, the effect is evident only when their skills in classifying trees are low or when the
environmental conditions significantly increase the risk of tree missclassification. The
simulation results also indicate that a greater number of bats in the colony increases the
efficiency of information transfer about hides and accelerates the rate of finding new cavities.
This is the first model to describe a mechanism that may promote the development of
bat cognitive abilities (correct classification of trees) and sociality in certain environmental
conditions. It is also universal (it may be applied in various studies of resource detection in
other animal species), and one of the first models that considers and integratea ecological,
sensoric, cognitive and social processes.
Summary
Understanding the mechanisms shaping the searching strategies for resources requires
knowledge about perceptual abilities, cognitive and social skills of animals and environmental
conditions in which the animals live. For study I have selected bats. Hollow trees are often
important resources for them. We examined the role of selected senses, the environmental
conditions and the cognitive and social elements for roost finding. I have conducted a number
of laboratory experiments and developed a theoretical model that explored the effectiveness
of different searching strategies for roosts. It has been show the important role of social
stimuli and cognitive skills (the ability to distinguish between trees with and without hollow)
for effectivenss of searching of roosts in specific environment conditions. Studies were
performed with the use of innovative techniques that made it possible. Studies for the first
time allowed for the comprehensive look at the processes of the searching for roosts. The
results will provide a reference point in the study on searching strategies not only bats, but
also other groups of animals.
Cited literature
Dechmann, D. K. N., S. L. Heucke, L. Giuggioli, K. Safi, C. C.Voigt, M. Wikelski 2009. Experimental
evidence for group hunting via eavesdropping in echolocating bats. Proc. R. Soc. Lond. B. Biol. Sci. 276:
2721-2728.
Eklöf, J. & G. Jones 2003. Use of vision in prey detection by brown long-eared bats, Plecotus auritus.
Animal Behaviour 66: 949-953.
Eklöf, J., A. M. Svensson, J. Rydell 2002. Northern bats, Eptesicus nilssonii, use vision but not flutterdetection when searching for prey in clutter. Oikos 99: 347-351.
Gaudet, C. L. & M. B. Fenton 1984. Observational-learning in 3 species of insectivorous bats (Chiroptera).
Animal Behaviour 32: 385-388.
Griffin, D. R. 1958. Listening in the dark. New Haven, Yale University Press.
Hammer, M. & R. Menzel 1995. Learning and memory in the honeybee. Journal of Neuroscience 15: 16171630.
Holland, R. A., I. Borissov, B. M' Siemers 20l0. A nocturnal mammal, the greater mouse-earęd bat,
calibrates a magnetic compass by the sun. Proceedings ofthe National Academy of Sciences of thę Unitęd
States of America 107: 6941-6945.
Kirnchi, T. & J. Terkel 2001. Spatial learning and nemory in the blind mole-rat in comparison with the
laboratory rat and Levant vole. Animal Behaviour
Lęwis, S. E. 1995. Roost fidelity of bats:
a
6I
:
I7 I
-l 80.
revięw. Journal of Mammal. 76:48l'496.
Niven, J. E. & S.B. Laughlin 2008. Energy limitation as a selective pressurę on the evolution of sensory
systems. Journal of Experimental Biology 211:1792-1804.
Rauschecker, J' P. 1995. Compensatory plasticĘ and sensory substitution in the cerebral-cortex. Trends in
Neurosciences
I
8: 36-43.
Schnitzler, H. U. & E. K. V. Kalko 2001. Echolocation by insect-eating bats." Bioscience 5l:557-569.
Siemęrs, B. M. & H. U. Schnitzler 2004. Echolocation signals reflect niche differentiation in five sympatric
congeneric species. Nature 429:. 657 -66.