Whisker touch guides canopy exploration in a nocturnal, arboreal rodent, the Hazel dormouse (Muscardinus avellanarius)
Dormouse numbers are declining in the UK due to habitat loss and fragmentation. We know that dormice are nocturnal, arboreal, and avoid crossing open spaces between habitats, yet how they navigate around their canopy is unknown. As other rodents use whisker touch sensing to navigate and explore their environment, this study investigates whether Hazel dormice (Muscardinus avellanarius) employ their whiskers to cross between habitats. We analysed high-speed video footage of dormice exploring freely in flat and climbing arenas in near darkness and using infrared light illumination. We confirm that, like rats and mice, dormice move their whiskers back and forth continuously (~10 Hz) in a motion called whisking and recruit them to explore small gaps (<10 cm) by increasing the amplitude and frequency of whisking and also the asymmetry of movement between the left and right whisker fields. When gaps between platforms are larger than 10–15 cm, dormice spend more time travelling on the floor. These findings suggest that dormice can actively and purposively move their whiskers to gather relevant information from their canopy at night. As this species is vulnerable to threats on the ground, we also provide evidence that joining habitat patches between dormouse populations is important for promoting natural behaviours and movement between patches.
KeywordsWhisker Vibrissa Active touch sensing Dormouse Climbing
BIOTACT Whisker Tracking Tool
The authors would like to thank Hazel Ryan for her continued help and support, especially in handling the dormice; also to Hazel Ryan and Angus Carpenter for their comments on the manuscript. We are extremely thankful to the Wildwood Trust for the use of their facilities and animals. The authors are also grateful to Ben Mitchinson for designing the climbing arenas and developing the portable setup, and to Holly Langridge and Fraser Combe for data collection support. Thanks to Brendan O’Connor for finding and translating some of the literature. Video analysis was performed using the BIOTACT Whisker Tracking Tool which was created under the auspices of the FET Proactive project FP7 BIOTACT project (ICT 215910), which also partly funded the study, alongside a small project grant from the British Ecological Society (BES). A big thanks goes to the CEB Research Group at MMU for listening to results summaries and advising about the project direction.
Compliance with ethical standards
All animals were part of a rescue and rehabilitation program, or from a breeding pool at the Wildwood Trust in Kent (UK) and approved by local ethics committees at each of the academic institutions and at the Wildwood Trust.
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