Scientists in Australia have been administering sheep with both valium and anxiety-inducing “party drugs” to help understand how to identify when animals are getting stressed out in farms. The findings of this barnyard bender were published in the journal Biological Letters.
As we all know, humans have several tell-tale signs that they're getting anxious; sweaty palms, hands trembling, stuttering, and so on. However, many of these “symptoms” are subjective and can vary from person to person regardless of anxiety levels. A more measurable way of tracking anxiety is how long a person is affected by something called “attention bias” – the idea that we pay more attention to things that seem threatening when we are feeling anxious, a bit like "a deer caught in headlights."
“Animals are not able to talk to express their emotions,” says Caroline Lee, an animal behavior expert at Commonwealth Scientific and Industrial Research Organisation in New South Wales, Discover reports. “We need to use other ways of understanding how they are feeling.”
This experiment hoped to find whether an attention bias could be identified in sheep. The researchers herded 60 sheep and divided them into three groups. One group wasn’t given any drugs, the second was given diazepam (valium) to suppress anxiety, the last was given a dose of Methyl-chlorophenylpiperazine (m-CPP), a serotonin agonist psychoactive drug that has been reported to induce anxiety in many animal species. It is also known as a cheap substitute for MDMA ecstasy.
Using food as a lure, the three groups were separately led into a walled area that featured a window with a shutter. When all the sheep had entered the area, the shutter would drop for 10 seconds to reveal a dog. Video cameras recorded how long the sheep's line of vision stayed glued to the shutter, even after the perceived threat had disappeared.
Overall, just one sheep was so chilled out it didn’t notice the dog. The sheep on m-CPP spent around 40 seconds staring, the control group stared for about 22 seconds, and the sheep on valium looked for just 14 seconds. The researchers also noted how none of the m-CPP sheep ate the food, while over half the valium sheep were content enough to chow down.
The results may seem obvious but the researchers say they clearly show that “attention bias” is an indicator of stress or anxiety in animals, as well as humans. What’s more, it requires minimal prior training to gauge and can be easily used to identify animals that are becoming overly stressed in farms.
Main image credit: Francisco Laso/Flickr. Creative Commons.