What guides lemmings movements through the snowpack?

• Published in: Journal of Mammalogy
• Main Authors: Poirier, Mathilde, Gauthier, Gilles, Dominé, Florent
• Format: Other/Unknown Material
• Language: English
• Published: 2020
• Subjects: Arctic; Ecology; Lemming; Movement; Small mammals; Snow; Lemmings > Écologie; Lemmings > Hivernage; Lemmings > Mœurs et comportement > Facteurs climatiques; Nunavut; Arctic Fox; Arctique*
• Online Access: https://hdl.handle.net/20.500.11794/39968; https://doi.org/10.1093/jmammal/gyz129

The presence of a snowpack, which may last up to 9 months in the Arctic, can provide insulation from the cold winter temperature for small mammals living beneath it, such as lemmings. Since lemmings have to move through the snowpack during that period, it is important to better understand how the physical properties of snow affect the way they dig tunnels. Here, we tested 1) whether lemmings systematically dig in the snowpack at the ground level where they can find their food plants, and 2) whether they choose the softest snow layer in which to dig, which is usually the depth hoar layer in the arctic snowpack. We found 33 lemming tunnels in 2017 and 2018 by digging through the snow at the sites of arctic fox attacks on lemmings. Contrary to our expectation, almost all the tunnels (32/33) were found to be higher than ground level, probably because of the presence of obstacles (i.e., melt-freeze crusts or hummocks) at the base of the snowpack. As predicted, all tunnels were dug in the soft depth hoar layer, which had a lower density than snow layers below and above it. Lemmings also showed a preference to dig their tunnels at the top of the depth hoar, just below a hard snow layer. Systematically digging their tunnels in the lowest-density snow layer, regardless of its height in the snow pack, could be a strategy for lemmings to minimize energy expenditure, which could improve their survival and chances of reproducing in winter. La présence d’un manteau neigeux, qui peut durer jusqu’à 9 mois en Arctique, assure une protection contre le froid pour certains petits mammifères qui s’y abritent pendant l’hiver, tels les lemmings. Cette neige est également susceptible d’affecter leurs mouvements, mais l’endroit exact où les lemmings creusent dans la neige pour se déplacer demeure peu connu. Nous avons donc testé 1) si les lemmings creusent toujours au niveau du sol, près de la végétation dont ils se nourrissent, et 2) s’ils choisissent la couche la plus molle pour creuser, généralement le givre de profondeur dans le ...