This is a difficult and a very personal blog for me to write. It’s been on my agenda for 7 years, but it has just been too painful to actually sit down and do it – until now.
All my dogs have been “other people’s mistakes”, as a colleague so eloquently summed up my history of dog-ownership.
Maggie was no exception.
I hadn’t owned a dog for a few years because of travel and work commitments, and wasn’t looking for one. The sister of someone at work had just offloaded a Springer and the dog had subsequently ended up at the RSPCA kennels. She was six months old and a ‘real handful’ apparently, not the kind of dog I was in a position to own, frankly. However, my work colleague was very persuasive and – rather reluctantly – I agreed to have her for a trial period.
I had never had a Springer before, and my knowledge of the breed was based on the dogs I had treated from the other side of the consulting room table. Maggie, as I renamed her, pretty much confirmed my thoughts about Springers and was indeed a handful. She went through, chewed and destroyed anything and everything she could get hold of – eye-glasses, pens, all kinds of shoes, clothing, plants, bits of wood, leads, dog toys… She had a very basic level of training and no recall.
Despite all that, she turned out to one of the most life-fulfilling dogs I had ever owned.
Maggie lived life to the full. She only had 2 settings, 0 and 100, interested in everything, she never stopped, except to sleep.
10 years later, in October 2011, she died suddenly, aged 11 years. Maggie’s enthusiasm for life had seen me through some very difficult times, I just didn’t see her untimely death coming and the shock of it was devastating.
This blog is a celebration of a dog’s life lived to the full. As ever, I prefer to take a scientific, rather than a sentimental approach to this. So here, I explore the nature of mourning and grief.
The anatomy and chemistry of sociality in animals
The most studied and so the most well-known hormone associated with the spectrum of feelings, or emotions related to caring, love, bonding, nurturing the young, and empathy is the neuropeptide oxytocin. Although we associate these kinds of behaviours and emotions with more complex animals, oxytocin has its roots a long, long way back in evolutionary time.
Oxytocin-like molecules can be traced right back down the evolutionary tree to the ancestors of invertebrates such as sea squirts, earthworms, roundworms and cuttlefish, where it acted as a kind of signalling molecule. Today, in these invertebrate species, oxytocin plays a role in reproductive behaviour and memory. In reptiles and amphibians, oxytocin controls reproductive social behaviour, and in birds and mammals it controls a much more complex range of social behaviours which are familiar to us as humans.
Nearly all of the recent studies on the role oxytocin in social behaviour has been directed at social animals, i.e. those that live in groups and cooperate with each other for the ultimate good of the group. Examples of social animals include humans, primates, domestic dogs and cats, bats, rabbits, rats, mice and many bird species. For example, there have been a number of studies showing the beneficial effects of patting and grooming your pet – it increases levels of oxytocin and prolactin (a neuropeptide that modulates stress), and decreases heart rate and levels of stress hormones.
So, what role does oxytocin play in solitary mammals that live most of their lives fending for themselves and avoiding close contact with conspecifics, such as some felines (leopards, tigers, jaguars, some small cats like the European wild cat), bears, rhinos and foxes?
In both social and solitary animals, oxytocin and prolactin play important roles in preparing the females of the species for parturition and, post-partem, the necessary physiological and emotional changes that the mother needs to care for her young. These neuropeptides also have an important role for the males too, it alters their emotional responses towards their offspring. For example, in some species it prevents the males from killing their offspring, while in others the male’s behaviour changes and they participate in the rearing their offspring.
The neural pathways in the brain responsible for social bonding, maternal care etc., through which oxytocin and prolactin have their physiological effects, run from a primitive area at the back of the brain called the ventral tegmental area (VTA). The VTA is also the origin of the brain’s complex reward circuits. These circuits are responsible for all the ‘good feeling’ emotional states associated with appetitive, approach behaviours that range in a dog from the satisfaction of finding food and eating it when hungry to chasing and catching a ball, and being trained with a clicker to press an alarm bell for the owner.
However, the social bonding pathway in the brain is different and distinct from main brain reward pathways. The social bonding network is associated with ‘soft and cuddly’ emotions and behaviours, with lots of body contact like touching and grooming. The brain reward pathways are associated with more goal-directed emotions and behaviours, and their chemistry is based primarily on dopamine.
Running alongside the social bonding pathway is another neural pathway involved with sociality, but in relation to the emotions and behaviours associated with social attachment rather than social bonding. This network has its origins in another primitive area at the back of the brain near the VTA called the periaqueductal grey (PAG).
In terms of evolution, all animals are little more than temporary storage vessels through which the organism’s genes are passed on from one generation to the next. Many animals ensure this happens successfully by reproducing huge numbers of offspring that are then left to fend for themselves. Although most of their offspring die before they ever get a chance to reproduce themselves, enough of them survive to ensure the ongoing survival of the organism. A good example is the frog and the huge number of tadpoles it produces.
Other animals like mammals take a different approach. They invest a great deal of time and energy growing their offspring in a womb and then, after giving birth, feeding and taking care of them until they have matured enough to start to become more independent and can take part in looking after themselves. From an evolutionary perspective, this kind of reproduction is very risky because it puts both the mother and her few offspring in danger of starvation, injury or even death.
Nonetheless, this kind of reproduction serves mammals very well. They have become a hugely successful and diverse class of animals on land, in the sea and in the air, and mammals represent some of the largest animals on earth.
The key to the evolutionary success of these animals is the development of the brain’s social attachment pathway. In precocial mammals like sheep, guinea pigs and many wild prey species such as gazelle, the young are born in a relatively mature state where they can stand up and move over to their mother to feed, keep warm and keep safe. In these animals, the social attachment pathway is functional at birth.
In altricial mammals, the offspring are born in a relatively immature state. They are all, but helpless and can do little more that wriggle and squeal. Postnatally, these animals are completely reliant on their mother until they mature enough to start walking and participating in their own care. In these animals, the social attachment pathway is inactive at birth and only becomes functional when the offspring are able to use it. Puppies, kittens and humans are all good examples of altricial animals.
Once active, the social attachment pathway becomes a vital system that helps ensure the survival of juvenile animals while they are small and vulnerable. This system works by ensuring that the offspring never stray too far or for too long away from their mother.
One of the best ways to see the social attachment pathway in action is during the lambing season.
You don’t have to observe a flock of sheep and their lambs for long before you see lambs becoming separated from their mothers, usually because the mothers move away to a new patch of grass to graze. But their lambs don’t notice because they’re too busy doing other things like playing with each other or exploring. When the lambs notice that their Mum has gone, what you will see is an immediate change in their emotional states and behaviour from happy/relaxed, to sheer panic. They soon spot their mothers and run over to them as fast as they can. Then you will see a ritualistic reunion of mother and lamb with lots of close body contact and licking which ends in the lamb taking a feed of milk from the mother.
The social attachment pathway is responsible for this entire sequence of events, and this is how it works.
In animals that use a social attachment pathway, the system needs to be primed before it can become properly functional. This is achieved by the young offspring forming a primary secure attachment with their mother. For mammals this is achieved as they suckle milk and their mother cleans and grooms them. The social bonding pathway and oxytocin is also involved in this priming process.
Like puppies and kittens, lambs need to go off and play with other lambs and explore their environments, it is a vital part of growing up into healthy, well-balanced adults. The social attachment pathway sits in the background in an OFF state in these young animals. It acts as a sentinel, getting feedback from the animal’s senses and keeping watch on how far and for how long the young animal is away from its mother.
Distance is a critical trigger here and it varies in different species.
When the social attachment pathway is activated, several chemicals are released into key areas of the brain. Corticotropin-releasing factor (CRF) is involved in the stress response. Glutamate is an excitatory neurotransmitter that amplifies the effects of CRF. However, the social attachment pathway has another even more powerful, but very nasty trick up its sleeve that cannot be ignored. It makes the animal stop in its tracks and take action – NOW.
It is no coincidence that for centuries philosophers, playwrights, poets and song-writers have expressed loss of a loved one in terms more associated with pain than in relationships. For example, hurt, damaged, broken hearts, love lies bleeding, etc.
Writer John Green sums this up perfectly, “…you can never love someone as much as you can miss them…“.
The discovery of the social attachment pathway explains why.
Figure 2 shows the brain’s complex pain pathway (black arrows). The roots of this pain pathway are located in the PAG and the parabrachial nucleus (PBN). From there, it connects up many areas of the limbic system and higher cortical structures such as the prefrontal cortex (PFC) as well. The social attachment pathway (red arrows) runs along the backbone of the pain pathway, and when it is triggered – by the lamb straying too far from its mother – its nasty trick is that it also turns on the pain pathway.
So, not only is the lamb’s stress response engaged, it also hurts, literally experiencing pain.
The only way that the lamb can switch the social attachment pathway off is to run back to its mother as fast as it can and re-establish its social attachment with her.
A number of studies have investigated the effects of complete isolation on very young social mammals, in some cases for over a year. When finally released, all these animals were irreversibly damaged and dysfunctional emotionally, and many later died. Some of the animals died during the isolation experiments. The important point here is that all these animals had their physiological needs met – food, water, warmth, ability to sleep etc. All that was missing was their need to form a social attachment. What killed them? Being subjected to chronic, unremitting, unresolvable pain. Their social attachment pathways were turned on, but the animals were unable to turn them off.
In solitary mammals, once the young are weaned and they can live independently, the social attachment pathway is permanently switched off as it no longer serves the animal’s ability to survive. In social mammals, the social attachment pathway remains active throughout life, but its influence on the animal’s behaviour varies and depends on the animal’s lifestyle. For herding animals like sheep, cattle, wildebeest etc. it ensures that animals remain in their group. This is particularly important for migrating animals like wildebeest, any member of the herd straying away and becoming isolated is easy prey for the many predators that follow the herd.
In humans, the social attachment pathway also remains active into adulthood. It plays an important role in maintaining the relationship between a couple. Humans are predominantly a monogamous species – that is, they partner up for life with a single individual (this remains true despite the expansion and popularity of today’s extended family structures). The social attachment pathway works alongside the social bonding pathway to ensure these relationships are maintained.
“Absence makes the heart grow fonder”.
- How often have you experienced these words of wisdom when away from home?
- How much do you miss your family, your pets?
- How often do you phone or text home, just to make some form of contact with your loved ones?
- Does your family miss you?
- Do your dogs miss you when you’re away?
- How do you feel when you return home and you are reunited with your loved ones?
The social attachment pathway is responsible for ALL these bad feelings, it is switched on to a low setting and keeps your attention focused on how much you miss your family whenever it can.
When you finally return home to your family, the period of separation is resolved and the social attachments with your loved ones are re-established. The social attachment pathway is finally switched OFF and that has a hugely reinforcing effect on your relationships. This is because the anxious loneliness – and most importantly – the pain has gone. These feelings are further reinforced by the cuddly/feely social bonding pathway as oxytocin and prolactinare released along with dopamine in your reward pathways. The euphoria of this climax of ‘good feelings’ lasts for days and further reinforces your special social relationships, this is the power of the social bonding and the social attachment pathways working together.
The interaction of these 2 pathways also explains mourning of a lost loved one, regardless of species. It explains why I was so upset when Maggie died and why it has taken me so long to write this blog around my experience of her loss.
The separation can never be resolved and so the social attachment pathway cannot be switched off.
This is what we call grieving.
Grief does resolve slowly over time, but it never goes away completely. This may be why we never forget our loved ones, and our memories of them are especially happy-sad around the anniversaries of their passing.
Separation problems in dogs; the role of the social attachment pathway
Recent exploration of the canine genome shows that dogs and wolves share about 99% of their DNA, in other words, dogs are wolves. However, the popularity of dogs as pets has grown enormously over the last 200 years, and this is reflected in the establishment of organisations such as the United Kingdom Kennel Club in 1873, when dog showing became a hugely popular past time. Dog breeding, and the refinement of the characteristics of specific dog breeds, became very focused on what dogs looked like, sometimes at the expense of what the dogs were originally been bred to do. This artificial selection process by humans also favoured the more human-friendly and human-sociable individuals within the various breed lines. We now know that this selection process has had an effect on the development of the social bonding and social attachment pathways of the dogs that live with us today.
The results of a study comparing the early sociality of wolf puppies with domestic dog puppies, all hand-raised by a single, dedicated foster-human, are revealing. By the time the pups were 5 weeks old, the behaviour of the wolf pups towards their human carers had changed completely, compared to that of the dog pups. The wolf pups had lost interest in their humans, stopped making eye contact with them and began to become aggressive towards them. For the duration of the experiment, the dog pups always vocalised more than the wolf pups when left alone for short periods of time. These results show that, as they developed, the social attachment neural pathway in the dog puppies had become functionally different to the pathway in the wolf pups.
The great, late professor Ray Coppinger argued that one of the most significant genetic changes brought about by the artificial selection of domestic dogs was a switching off of the genes responsible for taking dogs from puppyhood through to adulthood. The reason that dogs are noisy, cute and playful – characteristics of most young, social mammals – is because, like Peter Pan, they never grow up.
A side-effect of the domestic dog’s arrested juvenile state is their absolute need to form strong, long-lasting social attachments. What is really interesting here is that at an early age, puppies start to show a preference to form these social attachments to the humans around them instead of to their own mothers or siblings. This preference towards humans remains for the rest of the dog’s life. They do form attachments with other dogs, but the nature of the relationship is different. It appears to be more like the relationship we have with our own brothers and sisters, which is clearly different from that which we had with our mothers as young children.
All of this explains why so many dogs have separation problems.
There are around 7.8 million dogs in the United Kingdom and an estimated 1 in 4 homes have a dog. FIVE million of these dogs are left home-alone for 3 hours or more every day, and many of these dogs suffer terribly as a result. Dogs can learn to manage being left on their own, but this must be done gradually while they are still puppies.
The dog’s unique social attachment pathway has a another sting in its tail.
The isolation studies on very young social mammals mentioned above also investigated the strength of this apparent need to form social attachments. The researchers wanted to know if there was a limit to the young animals’ tolerance to punishment by the attachment figure as a form of rejection. What they found was shocking. Contrary to what we might guess would happen – i.e. these young animals would start to avoid making contact with the abusive attachment figure – the exact opposite happened. The more abusive the attachment figure became, and the more stressed and upset this made the young animals as a result, the harder the young animals tried to make contact with the abusive attachment figure.
Translating these findings to dogs living with abusive families and the suffering these poor animals must endure cannot be imagined. I will leave you with this thought to ponder…
So, when his social bonding system is switched on, your dog feels ‘soft-cuddly’ and wants to be sociable with you. The social bonding network also switches on his brain’s reward system at a low setting to give him a richer and more enjoyable emotional experience.
When his social attachment system is switched on, your dog feels alone and isolated. However, the social attachment system also switches on his pain system too. Together, the 2 systems induce a very negative emotional state which compels him to seek out social contact as soon as possible. When your dog is unable to achieve this… …I will leave you with this additional thought to ponder…
Here is a toast to all the Maggie’s out there and all the wonderful things they bring to their humans,
and a HATS OFF to all the lovely dogs in the world who have so successfully hijacked our emotional systems, and we never saw it coming!
© copyright Robert Falconer-Taylor, 2017
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1. Maggie 1, the Springer Spaniel by Robert Falconer-Taylor Copyright © Robert Falconer-Taylor, 2017.
2. Schematic of the pain pathway in the brain. Copyright © COAPE, 2017.
3. Maggie 2, the Springer Spaniel by Robert Falconer-Taylor Copyright © Robert Falconer-Taylor, 2017.
I choose not to cite any.