For many mammals, a busy social life can be an important contributor to a long life. But some animals need more alone time than others, and failure to get it could be lethal, according to new research.

Consider the marmot. After spending 13 years tracking their interactions and life spans in Colorado, Daniel T. Blumstein, a biologist at the University of California, Los Angeles, and his colleagues found in a study published Wednesday in Proceedings of the Royal Society B that yellow-bellied marmots with more active social lives tended to die younger than those that avoided interactions.

“The difference in life span between the most social and the least social marmot was about two years,” said Dr. Blumstein. That’s significant considering that the average life span of a yellow-bellied marmot is about 15 years.

Marmots are a genus of large, squirrel-like rodents with sharp claws and furry ears. They are known as socially flexible animals: They prefer to live solitary lives, but will peacefully coexist with each other if the habitat demands it.