The Empathy of Rats
The more we understand about the rat, the more we see remarkable sentience
Rats have been stereotyped as sneaky, selfish thieves who care only about getting some cheese for themselves. But recent research suggests this is a completely wrong impression of rats. It has been estimated that more than half a million households in the United States have a pet rat.1 My father had three of them as pets, and it was clear the rats had a relationship with their owner.
In Science magazine in 2011, researchers from the University of Chicago devised an experiment to test how important is it for a rat to free a trapped rat. The experiment presented the rat-subject with two choices — five chocolate chips or another rat — both trapped in a tube. The researchers were surprised to find that the rats preferred to free a trapped rat, than to eat all of the chocolate (they did eat some of it). 2
A study in 2017 showed that rats were not only empathetic and were willing to experience discomfort to untrap a friend, but that the part of the brain that felt empathy was the same part of the human brain that feels empathy.
Rats generally dislike bright lights, preferring to stay in places that are dark or dimly lit, Schaich Borg said. But she found that when given a choice, most rats would enter a brightly-lit chamber if it could prevent another rat from receiving an electrical shock.
A series of molecular tests pinpointed which regions of the brain were active while the rats made these decisions. “The brain regions that encoded what the rat was choosing to do were the same ones we found in other studies to be involved in human empathy and moral decision making,” Schaich Borg said. “It’s fascinating that rats are using the same brain regions that we seem to be using, and it suggests that rats provide a promising avenue for better understanding the way the human brain makes decisions to help others.”3
So it seems rats act a lot like humans, even using the same part of their brain when engaged in the same kind of behavior.
Bartal and a multinational team of colleagues placed rats in a situation where either a cage mate of the same type of rat, or a different type of rat they had never met, was trapped. In the experiments, most rats learned to free their cage mate, but few rescued the stranger.4
So rats have empathy and a bias toward helping the rats they know over the rats they do not know.
In February 2025, scientists announced that they found mice who would try to resuscitate another mouse, using a tongue pulling technique to encourage it to breathe, as well as lip biting and grooming to try to revive their friend.
The researchers found the mice exhibited these emergency life-saving behaviors, triggered by oxytocin, a hormone that stimulates love and affection.5 They also found there were a lot of mice (less than 50%) who did not respond to try to save their friend, so I would make the observation that it appears there may also be a “bystander effect” among mice. The “bystander effect” occurs where someone observing another in distress being attacked or needing aid of another kind and decides someone else (some other mouse) will take care of the needy mouse — and they can be a bystander. Sentience we had perhaps not even considered.
The researchers concluded:
These findings add to the evidence that an impulse to help others in states of extreme distress is shared by many species.6
Illustration from Sun, Zhang, Huang, Tao, Seo, Tao, Zhang, “Reviving-like prosocial behavior in response to unconscious or dead conspecifics in rodents”, Science (25 Feb 2025) at https://www.science.org/doi/10.1126/science.adq2677 .
Understanding rats (and mice) better may help humans become more empathetic. The more we look like other species, the more we (humans) tend to be empathetic. Stated in scientific terms: “Empathy and compassion toward other species decrease with divergence of evolutionary time,” as the title of the article concludes.7 But we also tend to be more empathetic with species exhibiting similar emotions or behaviors, like dolphins or dogs. This is not simply anthropomorphizing (interpreting animal behaviors as if they are human and considering them to be human-like, e.g., dressing your dog in a Halloween costume). But rather it is a closeness that comes from observing similar behaviors while respecting the different perspectives of each species.
Regulation of the LabRat
There are species specific rules for laboratory animals, but the focus in this article is just the rat and the mouse. Guidelines have evolved over time to become more empathetic with the comfort of the rat in experimentation and captivity. The Animal Welfare Act8 is the legislative authority for developing regulations and guidance. The current guidance is developed by the National Academies, Guide for the Care and Use of Laboratory Animals, 8th ed..9 Guidance is not binding but can be adopted by a government agency and will be used for regulatory decisions. A court may even look to it for guidance in opinion.
Best practices have evolved toward being more humane. Where once rats were killed during experimentation in the presence of other rats, it was recognized that it was more humane to keep the other rats from observing or hearing other rats in distress in experimentation, e.g. rats screaming in pain. That, too, became recognized as stressing and it became more evident that rats should not be in distress at all. This also applies to how a rat is genetically engineered, and if it is engineered to have characteristics that make its life painful, for example, then the practice must be suspended and reported. More research on making rats comfortable has developed, and the most recent useful technique is “rat tickling”,10 which makes the rats happy and look forward to their handlers coming to tickle them.
Looking ahead
We are on a trajectory to stop experimenting on rats and mice, and it seems increasingly obvious that alternative means of testing using artificial intelligence to find the right molecule for a drug, for example. Behavior experiments might only be confined to any experiment we might also be willing to do on ourselves.
For animals even more like humans (primates) we are doing better, from living conditions to phasing out testing on primates. A retirement program was created in 2016 for some primates that are retired from NIH testing programs to live out their lives with more freedom and in more open spaces.11
Perhaps science is just catching up with what Indigenous America has known all along — that we are all related and we can learn from nature and the behavior of its animals. It has been observed that the more a society can feel empathy for all of its members including animals, the more advanced it has become. It has also been observed that empathy correlates with emotional intelligence in a society.12
We could use more of that.
https://vetmed.illinois.edu/2017/02/06/rat-virus-one-health-approach-2
https://www.nih.gov/news-events/nih-research-matters/rats-show-empathy-too
Jana Schaich Borg, Sanvesh Srivastava, Lizhen Lin, Joseph Heffner, David Dunson, Kafui Dzirasa, Luis de Lecea, Rat intersubjective decisions are encoded by frequency-specific oscillatory contexts, Brain and Behavior (June 2017) at https://doi.org/10.1002/brb3.710 at https://onlinelibrary.wiley.com/doi/full/10.1002/brb3.710
Ben-Ami Bartal I, Breton JM, Sheng H, et al. Neural correlates of ingroup bias for prosociality in rats. Flagel SB, Wassum KM, eds. eLife. 2021;10:e65582. doi:10.7554/eLife.65582
https://www.science.org/doi/10.1126/science.adq2677
https://www.sciencealert.com/incredible-discovery-shows-mice-trying-to-revive-fallen-companions Article can be found here: https://www.science.org/doi/10.1126/science.adq2677 .
https://www.nature.com/articles/s41598-019-56006-9
https://en.wikipedia.org/wiki/Animal_Welfare_Act_of_1966
https://nap.nationalacademies.org/download/12910
https://nc3rs.org.uk/3rs-resources/rat-tickling
https://www.gao.gov/products/gao-16-392
https://pmc.ncbi.nlm.nih.gov/articles/PMC8054732/