They are not rodents with suicidal tendencies - and they do not seem to have psycological problems. Perhaps they simply can't do better. Any similarities to the human race are totally coincidental. They are able to swim and cross lakes more than 1 km wide. On the Northern hemisphere.
Most species populate regions in the tundra or taiga.
A few have specialized to live in savannahs and steppes, but I am not sure how much they have in common with the others. Due to lack of information, only the Latin and German names are available here. Their fur is coloured black, yellow and reddish brown on the back. They are living beyond the tree line in the mountains of northern scandinavia and nearby regions in NE Asia. Their body is about 13 to 15 cm with an additional tail of about 1.5 to 2 cm.