Any pet owner will tell you that dogs and cats have emotions1. Science supports these assertions2. We often think that other animals don’t have feelings. After all, we have less interaction with creatures like mice. Roughly 114.3 million American households have a dog, cat, or both3! Conversely, only 6.2 million have a small animal, which may include hamsters, rats, chinchillas, and rabbits.
Surprisingly, mice also have feelings. They are also more like humans than you may realize. That makes sense, given our close genetic relationship.
Genetic and Neural Similarities
All organisms with cells that have a nucleus or eukaryotes have a common ancestor4. You can think of DNA as an organism’s gene cookbook. Humans and mice share an astounding 90% of their DNA5, with about the same number of genes and 3.1 billion base pairs6. As they say, the devil is in the details. Nevertheless, mice are excellent lab animals because of these similarities.
Evidence of Emotions
Studying emotions in mice isn’t something new. Scientists developed a test called the Open Field Maze (OFM) in 1934 to investigate feelings in rodents. Research has been ongoing since it could have implications for treatments for humans. One study looked at the stress response in mice to learn how they could apply it to treat anxiety disorder and PTSD in people.
Mice and people have similar brain structures, including those involved with emotions like the amygdala. Its primary role is emotional regulation. It helps humans and animals interpret sensory input. The responses form the basis for fear memory, which, in turn, is critical for survival. It allows us to make life-saving decisions.
Both produce the so-called love hormone, oxytocin. It’s also associated with motherhood. One study found that injecting this hormone into mice could elicit maternal instincts in females. Interestingly, women produce it during childbirth. Doctors may use it to help them give birth during a drawn-out labor. The fact that mice respond similarly provides compelling evidence that the rodents also have feelings.
Other work has shown how mice share emotions, emulating humans. The findings indicate that they “catch” the feelings of their counterparts. This work provides compelling evidence that mice not only have emotions but that they experience empathy. That suggests higher feelings and processing in these animals.
Scientists have even been able to document facial expressions in mice. They have also correlated them with neural activity. That opens the door to learning more about emotions in mice and other animals. It’s worth noting dogs can express feelings equivalent to a 2.5-year-old child with less shared DNA than mice. The rodents may be capable of more than we think!
The answer to many questions we have about our pets and other animals often boils down to genetics. In this case, science provides unexpected explanations for how close humans and mice are. Emotions are a critical component of survival, with fear being one of the most important. Research has shown that these rodents have feelings, which may explain why they are so successful, evolutionarily speaking.
Featured Image Credit: Piqsels