Science - USA (2020-07-10)

histories and were thus able to determine
where a shortcut was truly novel. Second, we
ruled out the use of path integration. Specif-
ically,pathintegration,whichdoesnotrequire
external sensory input, is notorious for its ac-
cumulation of error ( 22 ),andthisistrueinbats
( 23 ). If the animals were using path integration,
then we would expect an increase in error
when they flew farther from their starting point
and when they turned more ( 22 , 24 , 25 ). We
found no correlation between the straightness
of the long-cuts and any of these parameters:
accumulated flight duration, flight distance, or
turning before the return (fig. S17). In addition,
the animals’ability to return from the trans-

location sites (in straight trajectories) could not

be explained by path integration.

Taken together, our results satisfy the re-

quirements of demonstrating visual map–based

navigation. That said, some caveats are in order.

First, we do not claim that the map is Euclidean

nor that the distances are accurately repre-

sented in the bat’s brain. Second, navigation

is a complex behavior that probably does not

always rely on a single strategy ( 2 , 26 ). Bats

occasionally switched from using map-based

navigation to alternative strategies like flying

along landscape elements such as highways

(Fig. 1F, fig. S6, and supplementary text, sec-

tion S6), but our data demonstrate that they

have a map-like representation of their envi-

ronment and can navigate according to this

cognitive map when necessary.

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ACKNOWLEDGMENTS

We thank N. Ulanovsky, T. Eliav, and M. Geva for reading and

commenting on the manuscript and M. Taub for assistance with

graphics.Funding:This research was partially supported by

the European Research Council (ERC–GPSBAT).Author

contributions:L.H. and Y.Y. designed the experiment. Y.Y., A.K.,

and L.H. conceived the analysis. L.H. and M.H. conducted the

experiment. Y.Y., A.K., and A.G. conducted the analysis. A.G.

performed drone imaging and analysis. Y.Y. wrote the manuscript.

L.H., A.K., and A.G. reviewed the manuscript.Competing

interests:The authors declare no competing interests.Data and

materials availability:All datasets included in the paper are

available on Mendeley ( 27 ).

SUPPLEMENTARY MATERIALS

science.sciencemag.org/content/369/6500/194/suppl/DC1

Materials and Methods

Supplementary Text, Sections S1 to S6

Figs. S1 to S25

Captions for Movies S1 to S4

References ( 28 – 38 )

Movies S1 to S4

GPS Tracking Data

11 June 2019; accepted 29 May 2020

10.1126/science.aay3354

SCIENCEsciencemag.org 10 JULY 2020•VOL 369 ISSUE 6500 197

20

40

60

1

0

Home range (km^2 )

04268 10 12 14

0

20

40

60

80

100

e

A

e

C day 88

B Koral

D E F

Home range

on day 60 (km

2 )

Bat ID sorted

0 50 100

0

0.5

1

SI

Mean max altitude (m)

0

0.5

1

0 1000 2000 3000

Min distance (m)

0

0.5

1

40 60 80

p=0.001

R=0.75

p=0.002

R=0.73

p=0.64

R=0.13

Female

Male

Female

Male

Fig. 4. Translocation experiments reveal individual navigation capabilities.(A) Different individuals
(x-axis) tended to be more or less exploratory. They-axis depicts the bat’s home range on day 60.
“Koral,”“Suki,”and“Nature”are bat names. (BandC) Three examples of translocations for a weak explorer
(left column), an intermediate explorer (middle column), and an extreme explorer (right column). (B)
Movements of the three bats before the translocation. (C) Return flights of the same three bats from the
translocation point. (DandE) The straightness of homing back from the translocation point significantly
correlated with: (D) the tendency to explore (depicted by the home range) and (E) the altitude flown by the
bats on the nights before the translocation. (F) The straightness of homing back did not correlate with
the nearest distance of previous trajectories to the point of translocation (i.e., how close the bat was to the
translocation point on previous nights).

RESEARCH | REPORTS