Variation in Soil Temperature Predicts Small Seasonal Shifts in Daily Activity Patterns of a Social Subterranean Rodent

TL;DR

This study shows that soil temperature changes influence the daily activity of subterranean mole-rats, causing small seasonal shifts in their behavior.

Contribution

The study demonstrates that temperature, not social factors, drives seasonal activity shifts in subterranean rodents.

Findings

Damaraland mole-rats show a daily activity peak around midday, coinciding with minimum nest temperatures.

Activity peak timing shifts by about 2 hours between seasons, linked to temperature changes.

Group-level foraging rhythms remain consistent across seasons despite low-level daily activity.

Abstract

Animals often show distinct activity rhythms which may align their behavior with favorable environmental conditions. In terrestrial species, daily and seasonal activity patterns are largely influenced by changes in photoperiod and temperature. However, subterranean animals experience weak or absent environmental variation due to minimal light exposure and reduced daily temperature fluctuations. Despite these conditions, many subterranean rodents display pronounced diel rhythms in physiological processes and locomotor activity, though the extent of seasonal variation remains unclear. In this study, we used radio frequency identification technology on wild groups of subterranean Damaraland mole-rats to assess their daily activity patterns. Our results show a population-wide daily activity peak around midday, which coincides with the minimum temperature at nesting depths and increasing temperature at foraging depths. The timing of this peak shifts by approximately 2 h between seasons. Neither individual nor group characteristics predicted the occurrence and timing of the activity peak, suggesting that temperature fluctuations, rather than social factors, are the main driver of seasonal variation in activity timing. Although Damaraland mole-rats remain active at low levels throughout the day, they display clear diurnal foraging rhythms at the group level that change little across seasons.

Graphical abstractDamaraland mole-rats time their foraging bouts in shallow tunnels (20 cm below ground) to the minimum temperature at the depths of their nests (40 cm below ground). When temperatures in the foraging tunnels begin to increase they will retreat back to deeper nests.

Damaraland mole-rats time their foraging bouts in shallow tunnels (20 cm below ground) to the minimum temperature at the depths of their nests (40 cm below ground). When temperatures in the foraging tunnels begin to increase they will retreat back to deeper nests.

Figures