Animal navigation: a noisy magnetic sense?

Journal Article (Review;Journal Article)

Diverse organisms use Earth's magnetic field as a cue in orientation and navigation. Nevertheless, eliciting magnetic orientation responses reliably, either in laboratory or natural settings, is often difficult. Many species appear to preferentially exploit non-magnetic cues if they are available, suggesting that the magnetic sense often serves as a redundant or 'backup' source of information. This raises an interesting paradox: Earth's magnetic field appears to be more pervasive and reliable than almost any other navigational cue. Why then do animals not rely almost exclusively on the geomagnetic field, while ignoring or downplaying other cues? Here, we explore a possible explanation: that the magnetic sense of animals is 'noisy', in that the magnetic signal is small relative to thermal and receptor noise. Magnetic receptors are thus unable to instantaneously acquire magnetic information that is highly precise or accurate. We speculate that extensive time-averaging and/or other higher-order neural processing of magnetic information is required, rendering the magnetic sense inefficient relative to alternative cues that can be detected faster and with less effort. This interpretation is consistent with experimental results suggesting a long time course for magnetic compass and map responses in some animals. Despite possible limitations, magnetoreception may be maintained by natural selection because the geomagnetic field is sometimes the only source of directional and/or positional information available.

Full Text

Duke Authors

Cited Authors

  • Johnsen, S; Lohmann, KJ; Warrant, EJ

Published Date

  • September 2020

Published In

Volume / Issue

  • 223 / Pt 18

Start / End Page

  • jeb164921 -

PubMed ID

  • 32967977

Electronic International Standard Serial Number (EISSN)

  • 1477-9145

International Standard Serial Number (ISSN)

  • 0022-0949

Digital Object Identifier (DOI)

  • 10.1242/jeb.164921


  • eng