19 Feb 2020

Enrichment for Rats part 1 - Introduction

Most of us are aware of the 5 animal freedoms, supported by large welfare association like the RSPCA and ASPCA. These based on 5 domains of life that all animals have in common (including humans).

These 5 domains are areas of life that affect the wellbeing of the individual animal. They are:

  1. Nutrition
  2. Environment
  3. Health
  4. Behaviour
  5. Mental state

This is the first of a series of six articles that explore these domains and freedoms in relation to the care and wellbeing of domesticated rats. In this article, we will provide an overview of the domains, their impact on each other and on overall well-being. We will also consider why the freedoms are presented as “freedom from…” rather than dictating what animals actually need.

A useful tool for unravelling the connections between the 5 domains is to think about each one being at the centre of the others. The RSPCA do this with only one domain – mental state – as their graphic neatly shows.


It’s very clear that behaviour, nutrition, environment and health all have a major impact on an animal’s mental state. But perhaps we should begin by establishing what “mental state” is. Rats (as mammals) share the same basic emotions as humans and have the same neurological structures and chemicals for emotional responses in the brain. These core emotions are described by psychobiologist, Jaak Panksepp, in his book, Affective Neuroscience, using a beautiful model that makes sense of the evolutionary purpose of emotion.

Jaak describes emotions as systems that emerged and were able to provide animals with greater flexibility and consistency of behaviour when they were faced with a variety of environmental challenges. He whittles these down to four main groupings:

  1. Pain and the threat of destruction (Fear system)
  2. Body surface irritation, restraint and frustration (Rage system)
  3. Social loss (Panic system)
  4. Positive incentives (Seeking system)

These are basic emotional systems, but more sophisticated systems can develop, particularly around social aspects of survival. Systems have evolved for nurturing, lust, play and so on, within social species.

Pain and the threat of destruction - fear

The fear system developed to help an individual escape injury or death. This is the system we often call “fight or flight”, but it more accurately includes fight, flight, freeze, fawn (appeasement) and fool around (distract). Not all species employ all tactics. The fear system gives rise to emotions we label as alarm, anxiety, foreboding, terror and so on. It’s the system we trigger when watching a horror movie or looking at a final demand from the electricity company.

Body surface irritation, restraint and frustration - rage

This system developed to enable an animal to defend itself and is aroused by frustration when something happens to diminish freedom of movement or immobilise an individual (e.g. being cornered or caught in the grip of a predator). The neurological response energises behaviour and rage often results in a physical aggressive attack. We label rage emotions as indignation, hate, anger, frustration and so on. This is the system that’s triggered when someone cuts us off while we are driving – in this instance, the car becomes an extension of our body!

Social loss - panic

A mammal is born socially dependent. This system assures the strengthening of social bonds by creating separation distress in both the mother and the baby. This social separation anxiety continues throughout life for all social mammals. It leads individuals to fear exclusion from the group and includes emotions we would label as panic, grief, loneliness, separation anxiety and so on. Anyone who has ever ‘lost’ their child even for a few seconds will remember the panic this creates.

Positive incentives – seeking

Mammals have strong pleasure and reward systems that move them to seek the things they need to survive and reproduce, such as food, shelter, social contact, sex and warmth. It makes evolutionary sense that these systems have developed to ensure the animal is repeatedly seeking fulfilment of their survival and wellbeing needs. The seeking system involves emotions we would label as anticipation, hope, desire, connection and so on. This system is designed to help us (animals) cope with obtaining resources even when they are scarce. We (first-world humans) often live in a state of almost constant seeking because we have come to value the pleasure of fulfilled seeking above most other things. This is what drives you to go to the shop at 23.00 hrs for snacks!

Once we begin to see the commonality of all emotion to all species of mammal, we can begin to understand the impact that the other four domains (nutrition, health, environment and behaviour) have on a rat’s mental state. Emotions are constantly in flux depending on the wider environment, the availability of resources (like food, beds and other rats), the ability to engage in natural behaviours and a state of health that allows all the rest to happen.

A rat’s mental state is a direct result of the combination of emotions they are experiencing at any moment. It’s just as possible for a pet rat to predominantly experience fear, rage and/or panic during their life as it is for them to experience the positive incentives of seeking emotions. Our aim as rat guardians is to ensure that experiences of fear, rage and panic are minimised and seeking emotions are maximised.

So, let’s return to the 5 domains and look at how they all interact. To do this I’ll turn the tables and demonstrate that each domain has an impact on all the others. If this is so, we can replace the central circle in the RSPCA picture with any of the domains – and the concept still holds true. This is essential information in realising that enrichment is fundamental to the wellbeing of a rat, just as the expression of natural behaviours is.

The impact of nutrition on behaviour, the environment, health and mental state

The availability of appropriate food (even better, quality nutritive food) is fundamental to a rat’s well-being. Beyond just getting basic rations, rats can be affected by the frequency and anticipation of regular food, deficiencies in their diet, personal preferences, neophobia, fasting periods and many more food-related issues. But for now, let’s just consider a group of rats who are underfed either in terms of actual food or in terms of the nutritional content of the food.

Will this impact their health? Of course, as good immunity, disease processes, energy levels and condition are all influenced to a large degree by nutrition. A malnourished rat is more prone to infection, lethargy, poor condition and a host of potential deficiency issues in their body. This will then impact their ability to manipulate their environment and engage in natural behaviours. They may struggle to maintain comfortable body temperature or try to conserve energy by reducing climbing, digging and so on. If food is scarce social relationships can also suffer and social stress can become a predominant emotional experience.

The impact of the environment on nutrition, health, behaviour and mental state

Many things can create a hostile environment for a rat, including:

  • the presence or smell of predators,
  • social stress within the cage group,
  • ultrasonic noise stressors (such whines from light bulbs and LED lights on appliances),
  • loud noise stressors (e.g. loud metal music, washing machines, human banging and clattering),
  • bright lighting,
  • intense perfumes and chemical smells
  • solitary and - for many rats – paired living,
  • lack of enrichment,
  • dry or hot environmental temperature.

Any environmental stressor can have an impact on well-being by disrupting sleep, depleting immune system function, reducing sociability, reducing food intake and creating a physical/mental state that we humans would call depression. Therefore, the environmental domain – including cage enrichment – can be central to peak functioning in the other domains of nutrition, health, behaviour and mental state.

The impact of health, on nutrition, behaviour, environment and mental state

This is probably the easiest of the domains to visualise affecting all the others. A sick rat is less likely to eat well, process food normally, engage in a full range of natural behaviours, or engage with and manipulate their environment. They are more likely to suffer from a negative mental state because of pain, disrupted sleep, panic (as with respiratory illness), anxiety and fear.

The impact of mental state on health, nutrition, behaviour and environment

Most of us are fully aware of how much mental state affects all other aspects of life. If we feel anticipation, hopefulness or desire, we tend to eat well, engage with our environment, seek out social relationships, invest in our health and engage in our natural behaviours. The opposite is true when we are feeling anxiety, anger, grief or panic. The same applies to all mammals. 

The impact of behaviour on health, nutrition, environment and mental state

Engaging in natural behaviours such as climbing, digging, foraging and problem-solving has a big impact on rat health by significantly increasing activity and honing proprioceptive skills. Mental well-being benefits because the seeking behaviours (exploration, foraging and problem solving) are stimulating the reward centres of the brain. The environment becomes a place of choice and control for the rat, which is central to well-being. Even nutrition is influenced as food becomes something that is sought, worked-for and found, rather than something that’s always available in a bowl.

In order to ensure maximum well-being for our captive rats, we need to ensure that all these domains are attended to and provided for. As each feeds into the others, any lack will impact all aspects of life.

So, why “freedom from…”

The RSPCA freedoms are as follows:

  • Freedom from hunger and thirst
  • Freedom from discomfort
  • Freedom from pain, injury or disease
  • Freedom to express normal behaviour
  • Freedom from fear and distress

This is simply a neat way of generalising all animal needs into one set of criteria. It says little about a species’ precise needs – as these vary widely – and any prescriptive care information would have had to be peppered with a thousand caveats.

But it’s easier (and more informative) for us to think about what rats DO need, than what they DON’T. And that’s what we will discuss in the rest of this series.

Article by Alison Campbell (© 2020),
If you'd like to read more of Alison's content, you can find her at Ratwise!

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