The study, which is published in the scientific journal Proceedings of the National Academy of Sciences, has been conducted by an international research team.
The Norwegian lemming belongs to the genus Lemmus, which includes three more species in the tundras of Eurasia and North America, and the researchers have analyzed DNA from two of these, the Siberian lemming and the North American brown lemming. In addition, they have examined DNA from fossil lemmings from the last ice age.
Spotted fur
Interestingly, the Norwegian lemming is the most distinct species. It is alone in having a spotted fur with yellow, black and reddish-brown markings. It is also unusually aggressive. One might think that it separated from the other lemming species a very long time ago.
But that is not the case. According to the study, it separated from the western population of the Siberian lemming only 34,000 to 36,400 years ago, just before the coldest period during the last glaciation. It is thus one of the youngest animal species on Earth.
Large genetic differences
After the separation, the gene flow between the Norwegian lemmings and the Siberian lemmings ceased, which suggests that the Norwegian lemming became isolated at that time. Today, it is found in the mountains of Norway and Sweden, as well as on the Kola Peninsula in Russia. East of the Kola Peninsula, the Siberian lemming takes over.
Despite its young age, the researchers have found obvious genetic differences between the Norwegian lemming and the other lemming species. Some gene variants are unique to the Norwegian lemming, for example in the gene that controls the color of the fur, which probably explains the species' very special color pattern.
Roland Johansson/TT
Facts: Lemmings
TT
Lemmings are a small group of northern small rodents with six genera and about 15 species.
The most well-known genus is Lemmus with four to six species. This includes the Norwegian lemming (Lemmus lemmus), the Siberian lemming (Lemmus sibiricus), the Amur lemming (Lemmus amurensis), and the North American brown lemming (Lemmus trimucronatus). They all live in tundra environments.
The lemmings' closest relatives are the voles.
