caa a22 4500 463244877 CHVBK 20180405153322.0 cr unu---uuuuu 170326e20070701xx s 000 0 eng 10.1007/s00422-007-0158-0 doi (NATIONALLICENCE)springer-10.1007/s00422-007-0158-0 Animal navigation: the difficulty of moving in a straight line [Elektronische Daten] [Allen Cheung, Shaowu Zhang, Christian Stricker, Mandyam Srinivasan] In principle, there are two strategies for navigating a straight course. One is to use an external directional reference and continually reorienting with reference to it, while the other is to infer body rotations from internal sensory information only. We show here that, while the first strategy will enable an animal or mobile agent to move arbitrarily far away from its starting point, the second strategy will not do so, even after an infinite number of steps. Thus, an external directional reference—some form of compass—is indispensable for ensuring progress away from home. This limitation must place significant constraints on the evolution of biological navigation systems. Some specific examples are discussed. An important corollary arising from the analysis of compassless navigation is that the maximum expected displacement represents a robust measure of the straightness of a path. Springer-Verlag, 2007 Cheung Allen Centre of Excellence in Vision Science, Research School of Biological Sciences, Australian National University, 2601, Canberra, ACT, Australia aut Zhang Shaowu Centre of Excellence in Vision Science, Research School of Biological Sciences, Australian National University, 2601, Canberra, ACT, Australia aut Stricker Christian John Curtin School of Medical Research, Australian National University, 2601, Canberra, ACT, Australia aut Srinivasan Mandyam Centre of Excellence in Vision Science, Research School of Biological Sciences, Australian National University, 2601, Canberra, ACT, Australia aut Biological Cybernetics Springer-Verlag 97/1(2007-07-01), 47-61 0340-1200 97:1<47 2007 97 422 https://doi.org/10.1007/s00422-007-0158-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00422-007-0158-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Cheung Allen Centre of Excellence in Vision Science, Research School of Biological Sciences, Australian National University, 2601, Canberra, ACT, Australia aut NATIONALLICENCE 700 1- Zhang Shaowu Centre of Excellence in Vision Science, Research School of Biological Sciences, Australian National University, 2601, Canberra, ACT, Australia aut NATIONALLICENCE 700 1- Stricker Christian John Curtin School of Medical Research, Australian National University, 2601, Canberra, ACT, Australia aut NATIONALLICENCE 700 1- Srinivasan Mandyam Centre of Excellence in Vision Science, Research School of Biological Sciences, Australian National University, 2601, Canberra, ACT, Australia aut NATIONALLICENCE 773 0- Biological Cybernetics Springer-Verlag 97/1(2007-07-01), 47-61 0340-1200 97:1<47 2007 97 422 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer