Seasonal Changes in Locomotor Activity Patterns of Wild Social Natal Mole-Rats (Cryptomys hottentotus natalensis)

Kyle T Finn,Andries K Janse Van Vuuren,Tobias Süess,Markus Zöttl,Daniel W Hart,Nigel C Bennett

doi:10.3389/fevo.2022.819393

Kyle T Finn, Andries K Janse Van Vuuren + Show 4 more

Open Access

https://doi.org/10.3389/fevo.2022.819393

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Abstract

Differences in individual locomotor activity patterns may be linked to a number of ecological factors, such as changes in ambient temperature or photoperiod. Observations on subterranean mammals suggest that they exhibit diel rhythms despite the lack of visual cues in their underground burrows, but it is unknown how seasonality and individual characteristics affect their activity. In this study we use RFID technology to monitor daily activity patterns of wild, social Natal mole-rats (Cryptomys hottentotus natalensis) during the summer and winter to investigate how their activity varies with season and whether their activity depends on individual characteristics such as body mass, sex and reproductive status. We found that in winter, individuals were more active during the time with the highest soil temperatures, whereas in summer, they showed a bimodal activity pattern during early morning and late afternoon coinciding with cooler soil temperatures. Individual characteristics, including reproductive status, did not affect general activity indicating that reproductive and non-reproductive individuals contribute equally to cooperative behaviors. We suggest that the activity patterns may be a behavioral adaptation to avoid extreme burrow temperatures and a mechanism to maintain a stable core body temperature. We highlight the advantages of RFID technology to study wild small mammal movements.

Highlights

Animal locomotor activity patterns have been the subject of much interest in the study of animal behavior
It has been discovered that ambient temperature instead of the light-dark cycle may entrain circadian rhythms in body temperature, melatonin cycles and locomotor activity in some of these species (Allali et al, 2013; Farsi et al, 2020a,b)
Soil temperatures at < 7 cm and time of day were the best predictors of activity patterns in the heterothermic Natal mole-rat, with soil temperature varying significantly over the course of a day and between seasons

Summary

Introduction

Animal locomotor activity patterns have been the subject of much interest in the study of animal behavior. It has been discovered that ambient temperature instead of the light-dark cycle may entrain circadian rhythms in body temperature, melatonin cycles and locomotor activity in some of these species (Allali et al, 2013; Farsi et al, 2020a,b). Arid dwelling rodents avoid the hottest period of the day and by becoming nocturnal (Randall, 1993; Roll et al, 2006) Biotic cues, such as feeding time, food availability, social cues, or predation, may affect activity patterns (Mistlberger and Skene, 2004; Halle, 2006; Getz, 2009; Refinetti, 2015; Beale et al, 2016). It has been suggested that simultaneous activity in voles provides an individual with protection against predation due to “safety in numbers” or possibly confusing predators by a “swarming” effect (Gerkema and Daan, 1985; Inman and Krebs, 1987) and species may alter their activity patterns in response to predation pressure which may act as a weak zeitgeber (Getz, 2009; Vlasatá et al, 2017)

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