|
Northern collared lemming
Tundra biomes of Alaska; arctic islands of Canada, Northwest
Territories; Greenland; St. Lawrence Island and Wrangel
Island. They are mainly terrestrial and fossorial, however, this
lemming can also be found swimming in the arctic waters.
.
|
 |
 |
|
Northern collared lemming
The collared lemming is short and stocky with a very heavy coat year
round. Pelage varies with the seasons: in summer the coat is light
to dark grey with a buffy to reddish brown tone. Dark lines down the
back and on the sides of the head are characteristic, however, the
length of the stripe varies from ending just before the withers, to
continuing down the length of the back. The winter
coat color is uninterrupted white. Dicrostonyx is the only genus in
Rodentia in which the individuals have completely white coats in the
winter season.
The head and body length equal approximately 100-157 mm with a tail
of between 10 and 20 mm. This species is fossorial, developing a
unique double digging claw in the winter to break through the ice
and snow of the tundra. D. groenlandicus can easily be distinguished from other species of the
genus by its narrow rostrum, smaller, straighter incisors and the
unusually short hind foot.
Reproduction
The female estrus cycle lasts for 9.6 days, occurring several times
in the breeding season, which runs from January to September (it may
begin early depending on the severity of the weather). After a 19-21
day gestation, a litter of between 1 and 11 is born. A female
typically has two to three litters per year in the wild; however, in
captivity they can have up to five. The young weigh 3.8 g (average)
at partruition and are weaned at 15-20 days.
Behavior
Members of this species have a fossorial lifestyle, using tundra sod
as a substrate in the summer and snow in the winter (Wooding, 1982).
Their burrows can reach up to 6 meters long and 20 cm wide, and they
eventually lead to a "nest". Nests made of grasses are placed
beneath the snow or inside a snow bank. The males engage in polygyny
as the main breeding system. Nests are protected by the males, but
evidence of territoriality is inconclusive.
Populations cycles are typical of lemmings: every few years the
numbers peak, followed by a "crash" that some observers
have described as a mass suicide, although this is doubtful.
Food Habits
The diet of D. groenlandicus consists of willow buds, fruits,
flowers, grasses and twigs. They will eat mushrooms and mosses in
captivity. The morphology of the teeth suggests that they prey on
insects, but this behavior has not been observed by individuals in
the wild.
|
