Rats seem to emit ultrasonic squeaks of happiness just because they are in the company of another rat. Using newly developed miniature microphones that were placed on rats’ noses, scientists have been ...

Mice and rats vocalize. To us, many of the sounds they make are ultrasonic—at too high a frequency to hear. But if we slow the calls down, they sound like squeaks. And not all squeaks are the same.

When Abby Chronister started college six years ago, she found herself struggling with anxiety and depression. After class, she often retreated to her bed. That’s when she adopted her first two rats, ...