Sheep on Valium Teach Scientists about Anxiety

How do you know when a farm animal is unhappy? Animal welfare researchers wish they had easy ways to measure malaise in pigs, or stress in cows. But those tools are lacking—which is why scientists in Australia studied sheep they'd dosed with Valium. "Animals are not able to talk to express their emotions," says Caroline Lee, an animal welfare scientist at CSIRO in New South Wales. "We need to use other ways of understanding how they are feeling." One such way is to look for changes in behavior that give away an animal's mood. For example, when humans are feeling anxious, we pay more attention to things that seem threatening. Scientists call this an "attention bias." If farm animals do the same thing, then testing how attentive they are to threats could be a simple way to measure how anxious they are. Lee and her coauthors tested this idea with ...