Scatter feeding rats

The rat is a natural forager; finding its food wherever and whenever it can. Historically, we have fed our small, caged animals out of food dishes, but only by scatter feeding rats, can we allow them to mimic this natural foraging behaviour. Being a true omnivore and opportunistic by nature, means that despite their neophobic tendencies (reluctance to try new things) – rats will eat almost anything.

A large part of a wild rat’s ‘day’ is given over to seeking, finding, stashing and eating a myriad of different food-items, from roots and leaves, to insects and even faeces. Rats will get their nutrition where they can, but it is well documented that they can often go to great lengths to get their hands on something special. Rats will steal eggs from nests, dive for molluscs, raid stables for stored grain and scavenge for food waste in the rubbish left lying around our city streets. The desire to search for food is an instinct driven by thousands of years of evolution, which has created a small mammal capable of thriving in almost any environment, eating almost any combination of available food sources. Even in a domesticated rat, this instinct remains strong, and creating an in-cage environment that encourages foraging is both enriching and supportive of natural behaviour.

What is scatter feeding?

Scatter feeding refers to the act of spreading the rats’ daily allowance of food around the cage; hiding it under cage litter, in enrichment feeders or small cardboard boxes. When you are scatter feeding rats, there is no requirement for a food bowl other than for fresh foods, but these too can often be scattered. In many ways, the more imaginative the placement of food, the more enriching the experience of finding it can be for the rat.

Food from the rat’s perspective

scatter feeding rats
Out and about foraging

A rat is in some ways very human-like in its approach to food. Rats don’t just eat functionally – though in times of scarcity they will eat whatever is available – they also derive pleasure from eating. Rats have been shown to emit the same high pitched (above our natural range) pleasure noises when anticipating a delicious treat, as when being tickled and played with.

They often have strong preferences in relation to food, which are based on their own, their mother’s and their colony members’ past snacking experiences.

A rat can make a decision based on whether or not they know something, driven by the likelihood of getting a really desirable (high-value) food reward.

However, their overwhelming pattern of feeding behaviour – whether wild or domesticated – is foraging and sampling. A good chunk of their time is spent looking for food and then sampling anything unknown, in small amounts. This is done in order to establish physiological consequences – is the food safe? Desirable and undesirable food preferences can also be learned as an infant and weanling from the mother, and throughout life from other group members Rats in a colony will avoid the food that a scouting rat smells of, should that rat get sick.

Scatter feeding rats – why?

Imagine for a moment that you are a rat. You are designed to forage and have learned that some foods are both delicious and safe. Imagine your joy when digging about in one corner of your environment, you discover a really tasty morsel.

Scatter feeding rats, not only relieves the boredom that can arise from in-cage living, but it provides for the expression of natural behaviours (such as searching, digging, problem solving, foraging and sampling). Add to this the enrichment of the emotional life of the rat and it’s clear that from the rat’s perspective, this is a preferable way to feed.

Happily, there are also real advantages for us humans, when it comes to managing the different needs of individual rats within one cage group.

Managing the nutrition of a number of rats within a colony hierarchy, when feeding from a bowl, can be difficult. At best, there can be wide discrepancies in the rats’ weights, and at worse, a very low ranking rat can be bullied into not eating enough to maintain his health and well-being.

scatter feeding rats
Any food up here?

Scatter feeding rats helps to balance out the needs of each individual. A greedy rat can no longer hog the food bowl, and a dominant rat – distracted by his own search for the ‘best bits’ – is more likely to leave a low ranking rat in peace to feed. In the process of scatter feeding rats, food is distributed around the cage, on different levels and to some extent, hidden in more challenging places. With a little planning, it is easy to offer growing kittens food that larger adults cannot easily reach or gain access to.

Scatter feeding rats, also helps to make food last, especially where the rats have to work to access the food. This is preferable to a group of rats descending on a bowl at feeding time and leaving only scraps within a matter of minutes.

Stashing food is a natural rat behaviour and scatter feeding allows this to happen without a rat jeopardizing their share of the food. When competing around a food bowl, an efficient feeder will remain at the bowl and not leave to stash, thus consuming a larger proportion of the available food than a rat who leaves to stash.

Rats who are scatter fed exercise their minds and bodies in their search for food around the cage. This is one reason why it is a good idea to be imaginative, rather than just placing the food in the same area every day. This daily forage for food aids metal and physical fitness and well-being.

Scatter feeding rats – how?

At its simplest, scatter feeding is taking the food you would normally place into the food dish each day and spreading it around the cage. The more effort you take about making food accessibility a challenge, the better! Only very old and sick rats need food to be readily available, and while these rats will still usually enjoy a rummage in the cage litter for a tasty morsel, their nutrition should be offered in a bowl for the main part.

Trust your rats to do what they have evolved to do. Forage. Caged rats can become lazy, but that doesn’t mean that they can’t revert to foraging if the opportunity is presented to them. Don’t be tempted to overfeed in case your rats don’t find every piece of food. This will lead to selective feeding (eating only the most preferred foods), wastage and the rats becoming overweight.

When scatter feeding rats, your aim is to find very little uneaten food around the cage when you come to clean out. Monitoring this waste food alongside the condition and weight of your rats (visually), will help you to get the amounts right. When you feed fresh food (unless your rats are on an entirely fresh food diet), only give about a dessert spoonful, per rat, per day and remove any uneaten fresh food after 12 – 24 hours depending on the ambient temperature.

I’ll be looking at some enrichment ideas for feeding in a future post

Behaviour Components in the Feeding of Wild and Laboratory Rats S. A. Barnett Behaviour Vol. 9, No. 1 (1956), pp. 24-43

Dot Paul, University of Georgia. “Rats Capable Of Reflecting On Mental Processes.” ScienceDaily. ScienceDaily, 9 March 2007.

Brenes JC, Schwarting RK. Physiol Behav. 2015 Oct 1;149:107-18. doi: 10.1016/j.physbeh.2015.05.012. Epub 2015 May 17.

Individual differences in anticipatory activity to food rewards predict cue-induced appetitive 50-kHz calls in rats.

The emotional life of the rat

Before considering the emotional life of the rat, we must begin by trying to define an emotion. This is a really difficult concept to pin down with words, especially since definitions vary between different areas of scientific study. This is my attempt.

An emotion is a conscious experience that is felt. It is essentially a biological reaction to environmental or social triggers; a cascade of neurotransmitters in the brain – and hormones around the body – that creates a felt experience, which is informed by external circumstances and (especially for humans) by thought.

Six basic emotions

It is widely recognised that there are basic emotions which are experienced by many animals, including all mammals, and these comprise:

  • anger
  • fear
  • disgust
  • joy
  • sorrow (grief)
  • surprise
    Why did emotions evolve?
emotional life of the rat
Strongly bonded rats

Within social grouping animals (including humans), emotions seem to have evolved to catalyse relationships and allow fluid adaptive behaviours. Social environments are not static, and individuals who are able to adapt in respect to relationships with the group – and individuals within it – are more likely to thrive and reproduce.

Can we measure the emotional life of the rat?
Much scientific study has been done to understand the nature of the emotional life of higher mammals, such as rats. There is a growing wealth of evidence to suggest that rats not only experience the basic emotions listed, but that they can show various aspects of empathy, cognitive bias and other ‘higher’ emotions.

However, because the emotional life of the rat (or any non-human animal) is difficult to measure or quantify, it is also impossible to accurately say “This is how it feels to be a rat.” All we can do, is study the available evidence and draw our own conclusions from it. One way of describing emotion at a functional level – rather than when they are muddied by cognitive processes; as they are for humans – is that an emotion is an evaluation of an event (either consciously or subconsciously) in order to determine how the event will impact a goal. As an example: if the goal of a rat is to be safe – a major goal for all animals, but perhaps closer to the surface for those who might easily become someone’s dinner – then the goal would be impacted differently by different circumstances. If a rat were to smell a passing cat, there would be a negative impact – I do not feel safe – experienced emotionally as fear. If a rat was resting in a warm nest, with a relative asleep beside him, there would be a positive impact – I feel safe – experienced emotionally as happiness (comfort, contentment). In each situation the feeling is driven by different physiology. The cascade of neurotransmitters and resulting hormonal soup in response to smelling a cat, would include stress hormones like cortisol and adrenaline, to initiate a freeze-flight-fight response. The resting rat, in the company of a bonded friend, would be experiencing the calming effects of neurotransmitters like serotonin and oxytocin, enhancing the feeling of well-being and restfulness, as well as increased relational bonding.

What about love?
emotional life of the rat
Cross species bonding

Note that love is not considered to be one of the basic emotions shared by all mammals. When considering the emotional life of a social mammal, such as an elephant, dog or rat, I think we would be foolish to discount their ability to experience a feeling of deep bonding. The real difference is that, as humans, we often over think our emotional world, write books about it and make Hollywood films to popularise our fairytale princess version of its expression. Many of us are confused about what love really is. Love is – biologically – a feeling of deep bondedness, and can occur within or across many species. It’s not special as an emotion, in as much as it “works” in the same way as the others; our bodies produce a physiological response to our evaluation of an event that impacts on our goals. In this case the goal may be to belong, to feel safe, to be protected, to nurture, or to reproduce. Grief at the loss of a life long companion is an indication of deep-bonding in rats, as is much of their day to day social behaviour, such as non-self-grooming and the favouring of their familiar human over all others.

The emotional life of the rat

The research available into rat behaviour, shows that rats show empathy, cognitive bias and learned helplessness, as well as some higher cognitive behaviours, such as, being able to base their decision-making on what they are aware that they do – or do not – know. They have some concept of ‘self’ and a sense of ‘other’ in terms of friend, predator or prey. They co-operate socially and demonstrate morality in the widest context of the word – knowing (and often doing) what is right for the good of the group.

Empathy: this is a sophisticated social emotion based on sharing (experiencing) the emotion of another creature, in a given set of circumstances, made more intense by having experienced something similar yourself in the past.

The experiment detailed above, demonstrates that a rat will show empathy in working to help another rat in distress, and all the more so, if they have previously experienced the same circumstance themselves.

Cognitive bias: this refers to the way that decision-making is affected by a pessimistic or optimistic emotional state, at the time of making the decision. Rats who were tickled and played with by their human, before being given a task to complete for either a great food reward, or a mediocre food reward, took a more optimistic approach to their decision making, than those who were not positively primed.

emotional life of the rat
Capable of desperate grief and depression

Learned helplessness: this is a feeling that arises in many species, when all choice and control over their environment is removed. When bad things happen, regardless of what we do to try to stop them,  learned helplessness kicks in and we stop trying. It’s a “shut down” state of passive acceptance of whatever happens, akin to depression. Loss of control over one’s environment will lead away from mental and physical well-being, towards stress, passivity, social anxiety and aggression. This happens across many species. Elephants, for example have been shown to suffer from Post Traumatic Stress Disorder (PTSD), when orphaned as youngsters in violent circumstances. Choice is considered to be so important to well-being, that simply knowing there *is* a choice is enough to help overcome adverse situations.

Before closing, I would like to suggest that although we might have a superior cognitive ability than other mammals, many species are superior to us in other ways. Rats hear and communicate in ranges we can only experience with electronic help. Dogs smell vividly and their experience of the world through scent is so much richer than ours, that it would be hard for us to imagine – let alone experience – it. Bats can catch an insect in the pitch black while flying! To see other mammals as ‘lesser’ than us is an inaccurate evaluation. In many ways the emotional life of the rat may be far richer than ours, because it is probably less affected (and devalued) by thinking. Rats, in common with many mammals, *feel* life. We, very often, *think* it!

References:

Excellent website with ongoing new articles about the emotional life of animals.

Scruton, R; Tyler, A. (2001). “Debate: Do animals have rights?”. The Ecologist 31 (2): 20–23. (looks at the work done on the physiological responses in animals when undergoing ’emotional’ experiences).

Rygula, R; Pluta, H; Popik, P. (2012). “laughing rats are optimistic”. PLoS ONE 7 (12): e51959. doi:10.1371/journal.pone.0051959. (rats showing the cognitive bias effect).

Ruchey, A.K; Jones, C.E; Monfils, M.H. (2010). “Fear conditioning by-proxy: social transmission of fear during memory retrieval”. Behavioural Brain Research 214 (1): 80–84. (rats showing empathetic behaviours).

Panksepp, J.B; Lahvis, G.P. (2011). “Rodent empathy and affective neuroscience”. Neuroscience and Biobehavioral Reviews 35 (9): 1864–1875. doi:10.1016/j.neubiorev.2011.05.013.