The hormone oxytocin plays a key role in long-term relationships. But a study of prairie voles finds that the animals mate for life even without help from the "love hormone."
A new book profiles some of the world's most fascinating felines, while telling how their job descriptions have evolved from rodent catchers to today's ambassadors for distilleries and breweries.
Rodents, primates and bats likely carry hundreds of thousands of viruses we haven't yet identified. But how do you know which ones might infect humans?