Potential use of a magnetic compass during long-distance dispersal in a subterranean rodent

Abstract

Geomagnetic sensitivity is present in a variety of vertebrates, but only recently has attention focused on subterranean mammals. We report the potential use of a magnetic compass in wild Damaraland mole-rats (Fukomys damarensis) during dispersal at two sites in the Kalahari region of South Africa. When the distance traveled was greater than 250 m, males and females dispersed in opposite directions and females preferentially chose a predominantly northeastern direction. This directional choice likely is due to the differing dispersal tactics between sexes. This evidence suggests that Damaraland mole-rats employ a magnetic compass during aboveground dispersal to assist in locating mates or a new territory. This study provides evidence to show how magnetic compass use could be useful in dispersal, an important ecological process for mammals.

Spatial population genetic structure and colony dynamics in Damaraland mole-rats (Fukomys damarensis) from the southern Kalahari

“…Since these and other dispersals cross the territories of multiple other established colonies, it is likely that these may represent aboveground dispersal events. Finn [ 57 ] hypothesized that dispersal distances greater than 250 m are likely to represent aboveground dispersal in Damaraland mole-rats, due to the high energetic costs associated with digging. Long-distance dispersal can thus be risky, exposing individuals to predation, aggressive interactions with conspecifics, loss of body condition and stress [ 31 , 39 , 58 ], while also trading off against cooperative contributions that they might otherwise have made within their natal group [ 59 ].…”

“…76%) taking on long-distance dispersal (> 250 m) than males (27 out of 47 male dispersers, i.e. 57%), although the number of male dispersers (47 individuals) was still higher overall than females (41 individuals) [ 57 ].…”

The Cognitive Ecology of Animal Movement: Evidence From Birds and Mammals

“…Birds may rely on a few features of magnetic fields including intensity (strength of the magnetic field), inclination (the angle between the magnetic field and earth surface), direction (polarity), and declination (the difference between true north and magnetic north) (Wallraff, 2005;Wiltschko, 2005, 2015;Mouritsen, 2018). While much of the research on magnetic compasses has been done in birds, there is growing evidence that mammals, specifically rodents and bats, also possess a magnetic compass (Holland et al, 2006(Holland et al, , 2010Oliveriusová et al, 2012Oliveriusová et al, , 2014Finn, 2021). Some large terrestrial mammals can spontaneously align their bodies with magnetic fields (Begall et al, 2013;Obleser et al, 2016;Painter et al, 2016;Červený et al, 2017), but it is unclear if they use an established magnetic compass for navigation.…”

Subterranean Life-Style Does Not Limit Long Distance Dispersal in African Mole-Rats

“…Indeed, very few individuals within a Damaraland mole-rat populations breed at some point in their lives (<8%; Jarvis and Bennett, 1993;Torrents-Ticó et al, 2018;Mynhardt et al, 2021;Thorley et al, 2021). Previous field studies of social mole-rats have shown that when individuals disperse, they frequently do so alone and rarely in coalitions (Jarvis and Bennett, 1993;Torrents-Ticó et al, 2018), and evidence suggests that dispersal occurs both above and below ground (Hazell et al, 2000;Bray et al, 2012;Patzenhauerová et al, 2013;Finn, 2021). By blocking themselves off into a section of the natal burrow, individuals can form a new territory via "territory budding" (Jarvis and Bennett, 1993;Lövy et al, 2013;Mynhardt et al, 2021).…”