24 Oct 2020

Enrichment for rats Part 3 - Safety

Safety - the context of enrichment  

All mammalian species have a primitive (ancestral) need to feel safe. In stating this, I am not implying that non-mammalian animals do not have this need – just that I don’t study them and am not certain. This requirement for safety underpins all mammalian emotions and behaviours.  

The need to feel safe is arguably experienced most strongly in prey species, including rats. When a rat has an encounter that threatens their survival, they are flooded with fear emotion. Fear of the threat is then learned and will inform future behaviour. It is easy to see how this system increases their chance of survival. Once learned (except for young babies who experience ‘fear-forgetting’) rats find it difficult to unlearn fear as is goes against their survival instinct to do so.  

Some fears have become so ingrained in a species that they appear in most individuals as an innate fear. Rats will often show a fear response to the odour of common prey species, such as cats and ferrets. In domestication, rats become habituated to this smell when they share their home with a cat, but those who have had no feline experience can show dramatic behavioural changes (in the short term) when one is introduced to their environment.  

Field studies in laboratory rats introduced to life is a ‘wild’ enclosure (who have had no habituation to the smell for hundreds of generations) showed a 100% fear response when the odour of a cat was introduced to the enclosure. They went into hiding for several hours, long after the odour had dissipated. The response in some pet rats seems to be much less extreme, possibly due to the influence of epigenetics if their ancestors have been habituated to the smell.  

Olfaction (smelling) is a rat’s primary sense and often influences the fear response. Even strong perfumes and chemical smells can trigger this, perhaps confusing and pushing the rat into fear biting or avoidance. All our efforts at enriching the rat’s environment should consider the effect of odours as well as of the physical enrichment itself. More on this soon.  

Felt safety and the process of feeling unsafe 

Felt safety relies on a much wider and more nuanced group of influences and is informed by a process called neuroception. This is a subconscious system that results in layers of awareness (within the nervous system of an individual) in response to factors that increase – or decrease – felt safety. It is a safety-o-meter that fluctuates within mammals under the surface all of the time.  

Neuroception is thought to be influenced by four main factors: 

  1. The internal state of the individual. 

  1. The state of others. 

  1. The nature of communication. 

  1. Environmental factors.  

The internal state of the individual 

All rats are functioning in the moment under the influence of emotional responses to what they sense and perceive. Senses including smell, hearing, touch (usually whisking), sight, taste, proprioception, temperature, time, and pain. Responses are triggered and mediated by what is happening in their body, environment, social group, and the nature of communication around them.  

Emotions are varied and experienced in degrees. Those considered to be experienced by rats include: 

  • Apprehension, fear, terror. 

  • Social bonding, nurturing, empathy, love. 

  • Frustration, anger, rage.  

  • Curiosity, anticipation, excitement, vigilance. 

  • Distraction, surprise, delight. 

  • Pleasure, joy. 

  • Panic, distress. 

  • Sadness, grief (depression). 

  • Lust. 

  • Disgust, loathing. 

  • Acceptance, trust.  

  • Remorse. 

It’s easy to see that rats have a varied and all-encompassing emotional life. Perhaps harder, is to try to imagine how it feels to live in the emotion of the moment, without applying layers of cognition to the experience. As humans, we tend to feel our thoughts, rather than experiencing the raw emotion in the moment. It can be difficult for many people to step outside of that (well-practiced) way of processing their experiences.  

Knowing what we know about a rat’s capacity for basic cognition, some rats likely apply some cognition in some situations. But overall, their processing is: 

  1. Sense (sensory input enters the body and is sent via the nervous system to the brain). 

  1. Perceive (the brain converts the sensation into a perception). 

  1. Emote (the perception triggers and emotional response). 

  1. Behave (the emotional response triggers a behaviour or set of behaviours). 

  1. Emote (the behaviour often triggers an emotional response). 

For example, let’s consider a group of caged rats who have just been fed. One rat in the group smells a delicious food odour – something familiar that they enjoy. Their perception is that the food is in their environment and they probably perceive that it was placed there by the human. The emotion of anticipation and excitement floods their body and drives a seeking behaviour as the rat follows the scent of the food.  

There are two possible endings – they find the food and are flooded with the emotion of pleasure, even joy. Or they find that someone else has taken the food and they experience frustration and even anger. Other behaviours may come on the back of this if they sense and perceive that a friend has the prize. Then their frustration and anger may spill out into challenging or even aggressive behaviour, which might reinforce their anger or (if they win the prize) lead to a cascade of surprise, delight, pleasure, or joy! 

In this example, we have only looked at the experience and emotions of one rat. All other members of the group are likely to also be sensing, perceiving, emoting, and responding behaviourally to this scenario, and emotions may vary from a fear response to distraction, or panic and distress. For some, felt safety will be challenged.  

The state of others 

It’s very clear from the example above that the emotional internal state of one individual affects another. This is something that is probably easier for us to relate to. We all have experience of how it feels emotionally to be around someone we are bonded too who is feeling strong emotions (try rage, grief, or joy on for size). Each emotional state in the other person will affect our own internal state.  

Another recognisable example would be meeting someone for the first time. A stranger will often create an immediate feeling of comfort (or discomfort) within us and we tune into their internal state. This enables us to make an instant judgement about whether we will ‘get on’ with the stranger. Internal states can change dramatically, but some are more consistent within individuals than others. So, time might prove us right or wrong in our initial felt response.  

For rats, the internal state of their social group is a massive source of information about what is going on in their environment. While foraging, one individual will be likely to sense and perceive danger first. The emotional fear response informs not only their behaviour, but the behaviour of the group. Emotions (especially without layers of cognition) are contagious and this is essential for individual safety in an unsafe world.  

The nature of communication 

The way that individuals communicate with each other affects the emotional state and felt safety of those individuals, but also of the wider group. Indeed, it is common for warning cries of multiple wild species to be at a similar frequency, with voice tones getting louder and pitch higher under the influence of fear. It is thought that this has evolved to allow information relating to safety to pass between species.  

Within rat social groups and in interactions with strangers, communication in terms of vocalisations and body language are used to inform an emotional response. The distress call of one rat will induce an emotional state of apprehension, fear, distraction, vigilance, or even panic in the others, depending on their own past experiences and current internal state.  

The excited chirruping (at frequencies inaudible to us) of excited and joyful rats as they anticipate or experience something pleasurable will draw other rats into the experience. Relational communication has a strong emotional content that can often be read between species – just try having an argument in front of a dog! Likely, a rat’s felt safety is also impacted by our own emotional communication.  

Environmental factors 

Since all emotional responses are initiated on the back of the rat’s sensing and perception, changes, and challenges in the environment can produce a range of emotional responses. These impact on felt safety to a large degree. Where emotions like fear, frustration, anger, disgust, and so on are triggered rats will usually begin to feel unsafe. Emotions such as pleasure, joy, social bonding, excitement, and trust can increase feelings of safety.  

Environmental stressors can easily reduce feelings of comfort and safety, even when there is no actual threat. As can internal states such as pain, hunger, and lack of sleep. Environmental stressors include things like bright lighting, lack of cover (especially for anxious or fearful rats), strong smells, and loud noises. Remember, a rat’s scenting and hearing are different from ours and more sensitive. Ultrasonic whines are aversive to rats – even though we aren’t even aware of them – and scents can be confusing and overwhelming at levels that are barely impacting us at all.  

Connecting safety to enrichment 

There are several ways that our efforts to provide an enriched environment can impact on felt safety – and equally how the perception of safety in a rat’s internal emotional environment can impact their ability to engage with enrichment.  

Rats have an ancestral bias towards neophobia (the fear of new things). This trait is thought to have increased in wild rats over the last few decades because of man’s persistence in trying to do them harm. Equally, it is likely to decrease in domesticated rats over decades, particularly in those who are raised in highly enriched environments and gain confidence from being exposed regularly to newness that results in excitement, pleasure, and reward.  

Individual rats can be neophobic to different degrees, and the fear can relate only to specific triggers depending on their experiences. Rats with a limited food repertoire may reject most new food, often needing to learn food preference from more experienced rats. However, many rats are willing to practice taste testing, where they sample a portion of new food and wait to see how it makes them feel. It’s important to use familiar, previously enjoyed food rewards in foraging and enrichment toys as this provides a degree of motivation to engage.  

New cage furniture and enrichment items can trigger some rats. I have heard of rats who suspiciously avoided a new hammock in their cage for many days before finally accepting and using it. For some rats change of any kind is enough to make them feel unsafe. Rather than accepting the status quo, these rats can be helped by the slow and underwhelming provision of new items for enrichment. Always one at a time, and always waiting for acceptance before the next item is introduced. Many fearful animals will begin to investigate new items, given time, so long as there is no coercion or pressure to do so.  

Felt safety is an internal emotional state that cannot be achieved in the presence of fear, anxiety, and hypervigilance. Feeling unsafe (for reasons, such as stressors in the wider environment or social stress) can prevent a rat from being able to engage with new enrichment. Indeed, if you have rats who are not displaying typical curiosity and investigative behaviours it is sensible to consider why not? Possible responses to this question include anything that impacts felt safety. There can, of course, be other reasons such as pain or illness.  

Finally, I would encourage you to always work to the abilities of your rats, only increasing difficulty in small stages when engagement and success are repeatedly achieved. Difficulty can be affected by the placement of an item in the cage or the degree of problem to be solved. For instance, hanging something from the roof bars which can only be reached from a thin, wobbly rope is a difficult physical challenge for many rats.  

Rats need to feel safe in terms of balance, movement, and the placement of their body in space. They are willing to take risks but not to risk serious injury for an uncertain benefit. Again, risk aversion varies greatly between individuals. But, not having much chance of reaching a reward without feeling physically unsafe is frustrating and demotivating. Equally, problem-solving challenges, such as food items placed inside multiple layers of small containers should be worked up to gradually, in stages. In terms of enrichment tasks, as with most things in life, practice is a necessary element of accomplishment.  

Alison Campbell © April 2020