Demonstrating a measurement protocol for studying comparative whisker movements with implications for the evolution of behaviour

Background Studying natural, complex behaviours over a range of different species provides insights into the evolution of the brain and behaviour. Whisker movements reveal complex behaviours; however, there does not yet exist a protocol that is able to capture whisker movements and behaviours in a range of different species. New method We develop a new protocol and make recommendations for measuring comparative whisker movements and behaviours. Using two set-ups – an enclosure camera set-up and a high-speed video set-up - we capture and measure the whisker movements of sixteen different captive mammal species from four different animal collections. Results We demonstrate the ability to describe whisker movements and behaviours across a wide range of mammalian species. We describe whisker movements in European hedgehog, Cape porcupine, domestic rabbit, domestic ferret, weasel, European otter and red fox for the first time. We observe whisker movements in all the species we tested, although movement, positions and behaviours vary in a species-specific way. Comparison with existing method(s) The high-speed video set-up is based on the protocols of previous studies. The addition of an enclosure video set-up is entirely new, and allows us to include more species, especially large and shy species that cannot be moved into a high-speed filming arena. Conclusions We make recommendations for comparative whisker behaviour studies, particularly incorporating individual and species-specific considerations. We believe that flexible, comparative behavioural protocols have wide-ranging applications, specifically to better understand links between the brain and complex behaviours

Genetic diversity of Blastocystis in non-primate animals

Blastocystis is an anaerobic protist, commonly inhabiting the intestinal tract of both humans and other animals. Blastocystis is extremely diverse comprising 17 genetically distinct subtypes in mammals and birds. Pathogenicity of this enteric microbe is currently disputed and knowledge regarding its distribution, diversity and zoonotic potential is fragmentary. Most research has focused on Blastocystis from primates, while sampling from other animals remains limited. Herein, we investigated the prevalence and distribution of Blastocystis in animals held within a conservation park in South East England. A total of 118 samples were collected from 27 vertebrate species. The barcoding region of the small-subunit ribosomal RNA was used for molecular identification and subtyping. Forty one per cent of the species were sequence positive for Blastocystis indicating a high prevalence and wide distribution among the animals in the park. Six subtypes were identified, one of which is potentially novel. Moreover, the majority of animals were asymptomatic carriers, suggesting that Blastocystis is not pathogenic in animals. This study provides a thorough investigation of Blastocystis prevalence within a wildlife park in the UK and can be used as a platform for further investigations on the distribution of other eukaryotic gut microbes

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

Supplementary Data

Data for the paper, which contains a number of workbooks: 1) The whisker and locomotion tracking measures on a flat floor; 2) The whisker and locomotion tracking measures on an inclined floor; 3) The distance and timings between the nose and foot placements; 4) Calibrated measurements of head and body. All descriptions of the data can be found in the paper. If you have any queries, please contact the contacting author - Dr Robyn Grant

Data from: Whisker touch sensing guides locomotion in small, quadrupedal mammals

All small mammals have prominent facial whiskers that they employ as tactile sensors to guide navigation and foraging in complex habitats. Nocturnal, arboreal mammals tend to have the longest and most densely-packed whiskers, and semi-aquatic mammals have the most sensitive. Here we present evidence to indicate that many small mammals use their whiskers to tactually guide safe foot positioning. Specifically, in eleven, small, non-flying mammal species we demonstrate that forepaw placement always falls within the ground contact zone of the whisker field, and that forepaw width is always smaller than whisker span. We also demonstrate commonalities of whisker scanning movements (whisking) and elements of active control, associated with increasing contact with objects of interest, across multiple small mammal species that have previously only been shown in common laboratory animals. Overall, we propose that guiding locomotion, alongside environment exploration, is a common function of whisker touch sensing in small, quadrupedal mammals

Electronic Supplementary Material from Whisker touch sensing guides locomotion in small, quadrupedal mammals

Contains extra tables of results; including 1) Sample numbers; 2) Measurements from the manually tracked footage; 3)Spearman's Rank correlation for offset, whisker span and forepaw width; and 4) Whisker measurement results for each species locomoting on an inclined floor