Richardson's Collared Lemming
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| Dicrostonyx richardsoni (Merriam, 1900) |
The Richardson's Collared Lemming, Dicrostonyx richardsoni is a small North American lemming. At one time, they were considered to be a subspecies of the Arctic Lemming, Dicrostonyx torquatus. Some sources believe that they are a subspecies of the Northern Collared Lemming, Dicrostonyx groenlandicus.
They have short chunky bodies covered with grizzled brown fur which varies from red-brown to grey-brown with a thin dark stripe along their back and a reddish grey belly. They have small ears, short legs and a very short tail. They have a reddish collar across their chest. In winter, they are covered with white fur and they develop enlarged digging claws on their front feet. They are 13 cm long with a 1 cm tail and weigh about 60 g.
These animals are found in the tundra west of Hudson's Bay in north central Canada. They feed on grasses, sedges and other green vegetation in summer and twigs of willow, aspen and birches in winter. Predators include Snowy Owls, mustelids and Arctic Foxes.
Female lemmings have 2 or 3 litters of 4 to 8 young in a year. The young are born in a nest in an underground burrow or concealed in vegetation.
They are active year round, day and night. They make runways through the surface vegetation and also dig underground burrows above the permafrost. They burrow under the snow in winter. Lemming populations go through a 3 or 4 year cycle of boom and bust. When their population peaks, lemmings disperse from overcrowded areas.
This animal was named after Sir John Richardson, a Scottish naturalist who explored the Canadian arctic.
[edit] References
- Rodent Specialist Group (1996). Dicrostonyx richardsoni. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 05 May 2006.
