Fully eight years less a month or two, since we did the 3 weeks of data collection on this project! Special thanks are needed for David McRae, skipper of the Kuroshio, for providing fantastic support of the field work, Louis Gosselin who, after I presented our stalled work at BMSC, suggested the paired analysis that solved so many problems, and alumnus Theora Holden who did the vast bulk of the slug tracking work.

The end result? Evidence that strong rare-earth magnets cause more erratic crawling paths as Tritonia exsulans move towards the magnets (yes the name T. diomedea is no more). The effect of the magnets led us to a new hypothesis for how the slugs (and maybe other animals) use a magnetic sense. For animals with no or poor spatial references because of either their environment or constraints of their sensory system, they may use the Earth’s magnetic field to simply help them move in straight lines – keeping movements efficient by avoiding unnecessary meandering.

Wyeth, R.C., Holden, T., Jalala, H., and Murray, J.A. 2021. Rare-Earth Magnets Influence Movement Patterns of the Magnetically Sensitive Nudibranch Tritonia exsulans in Its Natural Habitat. The Biological Bulletin: 000–000. doi:10.1086/713663.