A depiction of a joyful rodent: the rat's contented appearance
In a groundbreaking study, researchers have discovered that laboratory rats exhibit emotional expressions similar to those seen in various mammals, including humans. This revelation, led by emeritus professor of animal behaviour at the University of Colorado, Boulder, Marc Bekoff, sheds light on the complex emotional lives of these often-misunderstood creatures.
The study, which was conducted by Jaak Panksepp and his colleagues, renowned for their research on pain recognition in rats, focused on the rats' responses to positive emotions. It was found that happy rats, when tickled, would exhibit a unique open-mouthed expression, akin to a smile, with their ears turning pink due to increased blood flow. However, it remains unclear whether this reaction is a result of the rats' happiness or simply due to the increased exercise during tickling.
Luca Melotti, an animal-behaviour expert at the University of Bern in Switzerland, who has become a 'rat-tickling master,' observed that individual rats have distinct personalities. Melotti hopes to use this research to develop an automated system for monitoring an animal's emotional state by observing its expressions.
Bridget Waller, a researcher from the United Kingdom's University of Portsmouth, notes that 'Animals use facial expressions mainly to communicate with one another.' While it's not clear how rats use facial expressions to communicate, they tend to rely more on smell and touch than visual cues.
Intriguingly, previous research has shown that rats enjoy being tickled and emit a 'laughing' sound that is too high-pitched for humans to hear without special equipment. Furthermore, rats were found to avoid photographs of other rats grimacing in pain and preferred photos of rats in a neutral pose, suggesting a rudimentary understanding of positive and negative emotional states.
Bekoff argues for reducing the use of animals in laboratory research, stating that these days, there's no shortage of hard data showing that animals experience rich and deep emotions. He believes that understanding these emotional expressions could lead to better treatment and care for animals in captivity.
This study marks a significant step forward in understanding the emotional lives of laboratory rats. While it remains unknown if animals feel emotions the same way humans do, the discovery of the rat equivalent of a smile and the observation of rats 'laughing' provide compelling evidence that these creatures are capable of experiencing positive emotions. As research continues, we may uncover even more about the complex emotional lives of our rodent companions.
