Reindeer (Rangifer tarandus tarandus) were domesticated probably around 20,000 years ago in northern Europe and Asia. They are still kept by many herders in the Eurasian Arctic, who derive their livelihood from their animals. Reindeer from Siberia were imported into Alaska in the late 19th century in an attempt to provide income for indigenous people. In the 1930s an estimated 600,000 reindeer existed in Alaska, but that number is now down to about 20,000. It seems that most people didn’t quite see the point of managing reindeer when all they had to do was go out and hunt its wild cousin, the caribou (Rangifer tarandus granti). One of the unforeseen consequences of this endeavor has been the migration of reindeer into caribou herds and until recently it was unknown to what extent this influx has had an impact on the genetic diversity of caribou. A recent analysis of microsatellite DNA in caribou and reindeer in Alaska, however, shows that very little genetic introgression seems to have taken place into either species and the authors think the reason could be that hybrid offspring may have a lower chance of survival. It is interesting to note that their study also indicates that the Alaskan/Russian reindeer and the Alaskan and Canadian caribou are much more closely related to each other than either is to the Scandinavian reindeer.
Caribou, which can be found throughout Alaska and the Canadian territories, migrate often in large herds between their summer and winter pastures. The porcupine herd, for example, numbers in excess of 100,000 animals and covers a distance of over 2000 km on its yearly route from the Yukon to the calving grounds on the Alaskan Arctic coast (the very same area the US government is trying to open up for oil exploration). Many native people in Canada and Alaska still depend on these animals for their survival and they are becoming concerned that increasing human development and global warming may either affect the size of caribou herds or change their migration patterns.
From Michael Kubisch