Both study areas supported cyclic populations of collared lemming (Dicrostonyx groen-landicus) and brown lemming
(Lemmus trimucronatu,.s.; Gruyer et al., 2008, Krebs et al., 2011).
Except for parts of north central British Columbia and northeastern Manitoba, the brown lemming
today does not occur south of the sixtieth parallel.
In several rodents, females have been found to prefer dominant males as mating partners (e.g., brown lemming
; Huck and Banks 1982a,b; house mouse; Wolff 1985; Drickamer 1992; prairie vole and montane vole; Shapiro and Dewsbury 1986; bank vole; Horne and Ylonen 1996).
populations near Barrow undergo large fluctuations (Rausch, 1950; Pitelka et al., 1955; Thompson, 1955a, b; MacLean et al., 1974; Batzli and Pitelka, 1983).
Common Rat, Rattus norvegicus D-P Brown Lemming
, Lemmus sibiricus ++ ++ Collared Lemming, Dicrostonyx ++ +++ groenlandicus
Irruptions are periodic and unpredictable, generally coming when collared and brown lemmings
, their two primary Arctic prey, crash in numbers -- or when the snowy owl population just gets too high.
They found that male brown lemmings
(Lemmus sibiricus) much prefer the odour of virgin females to that of females that have just copulated.
Black bears, brown bears, caribou, hoary marmots, and brown lemmings
died within or were dragged into On Your Knees Cave in the millennia preceding the last glacial maximum.
Lemming population dynamics are complex and, Parmelee points out, the fluctuations vary between species as well as from higher latitudes (where only varying lemmings occur) to lower latitudes (where both varying and brown lemmings