Do subterranean mammals use the Earth's magnetic field as a heading indicator to dig straight tunnels?

Abstract

Overview

Subterranean rodents are renowned for their ability to create extended, straight tunnels, essential for efficient foraging and dispersal activities. Despite historical recognition of these navigation abilities since the 1950s, the mechanisms driving such directional precision have remained elusive.

Findings

This study analyzes the directional orientation of 68 burrow systems across five subterranean rodent species. Utilizing detailed burrow maps sourced from prior studies, a significant non-random orientation pattern was noted in most burrow evaluations. Specifically, notable orientations included north-south, NNW-SSE, and NE-SW directions across various species, suggesting a geomagnetic alignment. One species exhibited random burrow orientations.

• Fukomys anselli and F. mechowii predominantly showed NE-SW tunnel orientation.
• Heliophobius argenteocinereus tunnels were primarily north-south.
• Ctenomys talarum displayed a NNW-SSE tunnel orientation.
• Spalax galili showed random orientation in its burrow systems.

Conclusion

The findings support the hypothesis that the Earth's magnetic field serves as a crucial navigational aid in subterranean mammals, offering a biological basis for magnetoreception. This reveals not only the potential evolutionary advantages but also promotes the necessity for further experimental studies in magnetoreception.