07 Nov 2020

Enrichment For Rats Part 4 - Brain Function and Wellbeing

This article (article 4 in a series of 6) explores the role of the rat’s brain and reward systems when providing enrichment. We will look at why problem-solving is important, the processes a rat uses to solve problems, and how the rat’s reward systems ensure that certain behaviours are repeated.  

If we think about the unique physical adaptations that have evolved amongst some groups of animals (flight, sonar location, night vision, opposable thumbs, and so on) it is clear that many problems have been solved by the process of evolution itself.  

Cognition and the growth of the rational brain is a highly successful adaptation because with rational thought, insight, and cognition, come all manner of problem-solving skills, which bolster the specialised physical adaptations which a species already has.  

For instance, a corvid can fly to escape predation and reach food, but because they have also evolved a degree of cognition. They can use tools and create ordered systems involving multiple layers of problem-solving to reach food.  

All mammals have a seeking emotional system (as we discussed in article one of this series) which drives them to find food, evade predation by seeking shelter, find a mate, or forage bedding to line a nest to keep warm. As they seek, they naturally run into problems.  

Over time, many of these problems are solved and new information is passed between generations. Indeed, bumping into problems seems to intrinsically motivate mammals to find solutions.  

Because of this trait, it is not possible to equate solid problem-solving skills as being the result of abstract reasoning. All mammals problem solve, but not all mammals demonstrate reasoning.  

When our rats appear to do something ‘clever’, it may be that they solved the problem in front of them through instinctive motivation and trial and error. This is a process that requires little ‘cleverness’, which is important because animals with lower cognitive abilities still need to solve problems that are important to their survival.   

It was once thought that only humans had the ability to consider and reason, but this is no longer acceptable science. It would be more accurate to think of all animals as being somewhere along an evolutionary continuum in terms of brain development.  

However, it is not even actually one continuum. Some invertebrates who have developed quite independently from us for millennia show problem-solving behaviours – octopodes are one example.  

How are problems solved? 

There are three main levels of problem-solving, each requiring increasing degrees of thoughtfulness.   

Trial and error  

Routes to problem-solving can involve varying degrees of reasoning. At the most basic level are trial and error. This looks something like:  




Trial and error do not necessarily require any thoughtful consideration of the problem or purposeful action taken to solve it. Even so, they can be highly effective. Of course, for complex problem-solving cognition and reasoning can be applied to trial and error to find out what works, or doesn’t.  


Cognition is probably the next progression in terms of problem-solving – cognition asks, “What do I know that might help me here”? Cognition, as defined by the Oxford Dictionary, is “the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses.”  

Research has shown that rats are capable of cognitive thought; they can decide something based on what they know that they know (or don’t know), which is fairly sophisticated reasoning. They will probably apply some cognition to some problem-solving situations.  

Abstract reasoning  

At the higher end of problem-solving is abstract reasoning.  This means being able to look at a situation of which you have no personal knowledge of a solution – and being able to use abstract thought (based on previous unrelated experience) to create purposeful solutions. This kind of problem-solving is seen in species other than humans, including apes.  

The summation of a 2011 literature review, into the limits of abstraction in rats (and humans) stated: “We conclude that, within specified limits, rats are capable of using prior experience when faced with a learning situation that involves new stimuli. We interpret this ability as a rudimentary form of abstraction.”   

So, it seems possible that rats may problem solve using all three of these methods, at least to a degree. But not all rats will be equal, and it is noted anecdotally that rats who have practiced problem-solving skills from infancy onwards are more likely to be able to approach a new problem purposefully in later life.   

Problem-solving, seeking and motivation 

If a wild rat had poor problem-solving skills he would probably be destined for early death. All wild rats will learn and practice these skills from the moment that they can leave the nest.  

When humans say “My rats aren’t interested…” this usually results from:  

  • Little or no practice as babies (there is probably a critical period in terms of fully developing the brain areas involved).  

  • Little or no practice throughout adulthood. Very few skills are maintained at a high level of proficiency unless they are used regularly. The brain tends to be interested mainly in things that we demonstrate (through use) to be important to us. 

  • Little or no motivation. If everything you need comes easily, where is the motivation to try going to come from? That said, many rats are internally motivated to seek (water, food, shelter, social connection, warmth, comfort, and a mate) so will problem solve if needed, to do so. 

The seeking emotional system is the only top-level emotional system that offers rewards as motivation. Not only the reward of finding but the internal rewards of stimulated pleasure centres and the release of feel-good neurotransmitters, such as dopamine and serotonin. The reward of satisfying a need. 

But there is added reward and satisfaction in working on and solving a problem. Challenge and problem-solving opportunities have been linked in some species to increased well-being. 

Imagine taking an animal as capable of problem-solving as a wild is (hence their success) and placing him into a cage with very few challenges or problems to solve. Beds are provided, food arrives in a dish, safety is assured. A massive area of reward and well-being is removed from his life.  

We can kick back by challenging ourselves to create new and meaningful challenges for our rats. Foraging (for food, bedding, natural items, etc) is a highly motivational way to do this. The act of exploring and searching in the environment provides sensory stimulation and enrichment.  

That is what enrichment really means – embiggening the rat’s whole experience by providing opportunities for sensory stimulation, behavioural expression, problem-solving and emotional wellbeing.  

Some out of practice individuals may indeed by reluctant at first. Here are some tips on how to gradually exercise their ‘seeking muscles’ [note that here we discuss food-related foraging problems – there are many other areas of a rat’s life that can be similarly challenged]: 

  • Stop all predictable feeding. Continue feeding their usual mix but not in the usual way. You could put it into boxes or hide it around the cage.  

  • Slightly underfeed them in terms of dry mix. It is a natural state for animals to feel hunger and for that hunger to motivate them to look for food.  

  • Start easy and very gradually increase the difficulty to maintain interest and motivation. Constant frustration is demotivating and feeds the rage emotional system, causing social unrest.  

  • Ensure that you use high-value food (often fresh food) in foraging conditions that present more difficult problems. These might be hard to reach toys or those that require more sophisticated manipulation.  

  • Leave difficult puzzles (problems) in the cage for at least a week. If you anticipate this you can use high-value dry food that won’t spoil, such as mealworms, nuts, and pasta.  

Being presented with repeated challenges naturally increases motivation and reward, but also encourages the rat to think, which in turn increases problem-solving abilities.  

The more novel situations that are presented, the more robust your rats will be in this regard. If they fail and give up, lessen the difficulty of the challenge and offer lots of new and interesting problems, at a lesser degree of difficulty. Proficiency will almost always develop over time.  

Manipulating the environment – giving our rats back control 

All animals need to be free to exercise control over their environment. This is essential for mental wellbeing and confidence. This can mean solving problems like being too hot, too cold, or under threat, as well as how to get the bedding they want from the ground level to their cage-top hammock.   

Manipulating the environment means having an ability to decide what to do, and when and how to do it. It means being in control. Sadly, for caged animals, it is easy for us to remove control, primarily by not giving choice. An example that is easy to grasp is how a rat can manipulate their environment on a hot day. 

If they are in a cage in a warm room with the window on vent, but the curtains open, with an open cage set up, a couple of snuggly hammocks and deep litter, but no open water sources or shelves, it’s easy to see how they might struggle to self-regulate their temperature.   

They can’t change the external temperature and the setup of the cage offers little in terms of cooling opportunities. To give choice we could add in a wet towel covering part of the cage so that it is shaded and naturally cooler, a large piece of ceramic tile over some of the floor space, a couple of open water sources, some frozen vegetables inside ice cubes and an open flat hammock.   

This allows them to manipulate their environment to live at a comfortable temperature, rather than getting too hot. They can move from one area to another, have a dip in the water, chew some ice, or choose a cool sleeping place – essentially, they can solve the problem of feeling hot. 

The same applies to feeling cold, or hungry, or lonely, or unsafe, or sick. They need to be able to create the circumstances that feel good to them in any given situation.   

When asking whether our rats can manipulate their environment it is important to begin to ask questions: Can they move bedding to where they want it? Can they sleep alone without disturbance? Can they create a door here, or an exit there (hammocks/boxes)? Can they climb, run, and dig if that is what they are motivated to do? Can they breathe without having to smell an overpowering scent? Can they sleep without being woken by frequent sudden noise? Can they easily cool down? Can they easily warm-up?   

Offering a variety of litter, food, or bedding in a controlled way can allow the expression of preference. Usually, such tests should be repeated several times to ensure accurate observations remain unchanged.   

To conclude, remember that problem solving does not have to mean that you make huge efforts or give expensive toys. A new cage layout is a problem to be solved in terms of both investigating new items and establishing new routes around the cage. Make the most of every situation to create challenge and it becomes easy to maintain over time.  

© Alison Campbell, 2020 



Metacognition in the rat. Current Biology. 2007 Mar 20; 17(6): 551–555.  
Allison L. Foote and Jonathon D. Crystal  

Innovative problem solving in nonhuman animals: the effects of group size revisited.  Behavioral Ecology, Volume 26, Issue 3, 1 May 2015, Pages 722–734  
Andrea S. Griffin, David Guez 

Do Animals Have Insight? Recent research suggests that animals may solve problems the way humans do. Jan 28, 2013 Psychology Today