Friday, January 13, 2017

Do pets grieve for each other?

Owners report that dogs and cats exhibit behaviour changes when a companion animal dies.

Do companion animals grieve when another animal in the household dies? It is a question often asked of veterinarians, and the truth is we don’t know. Where an animal from a multi-animal household dies in a veterinary hospital, it is common for the owner to request that the other animal/animals see the body. One question I’ve always wondered is whether this helps other animals, or does it reinforce a fear of the veterinary hospital? Or neither?

We also see our fair share of animals who are lethargic or display other signs since the passing of a household member. Sometimes we cannot find a cause, at other times there happens to be an underlying illness.  I’ve seen enough of the latter to advise owners whose pets are lethargic or off-colour following the death of a companion animal to come in for a check-up.

We don’t know much about grief in animals. There are dozens of reports of elephants having very strong reactions to the death of a family member, and spending a lot of time exploring bones and carcases. There are reports that many primates continue to carry deceased offspring – for hours, days, weeks and even months. Then of course there are studies documenting the stress response in farm animals (for example, dairy cows and calves) when separated from one another.

Unfortunately, we can’t ask the animals themselves. But we are getting a bit better at measuring both negative and positive emotions in other species. For example, comparative study of nervous systems, behaviour and physiology evaluation, qualitative behaviour assessment, and detection of cognitive bias are often used. Observations can also highlight trends in behaviour which can be further explored.

A paper by Jessica Walker and colleagues found that, at least from the owner’s point of view, the behaviour of dogs and cats changed following the loss of a conspecific.

They analysed 279 surveys from owners who had lost a dog or cat in the previous five years. According to the owners surveyed, the most common types of behavioural changes related to affectionate behaviour and territorial behaviour. Thus 35 per cent of dogs demanded more attention from their owners following the passing of a conspecific, 26 per cent became more clingy or needy, and 10 per cent sought less attention from the owner. A total of 60 per cent of dogs showed changes in territorial behaviour, with 30 per cent seeking out their former companion’s favourite spot, and 14 per cent spent increased time hiding. Changes in sleep behaviour were common in dogs (42 per cent), with 34 per cent sleeping more than previously. Both the amount and speed of eating changed, with a decreased amount eaten by 34 per cent of dogs and reduced speed of eating in 31 per cent. The behaviour changes lasted from 2-6 months.

Cats differed, although when it came to behaviour changes relating to affection they were similar to dogs, with 40 per cent demanding more affection, 22 per cent reported to be more clingy or needy and 15 per cent seeking less affection. Almost two thirds showed a changed in territorial behaviour, mostly (36 per cent) seeking out the other animal’s s favourite place. Unlike dogs, cats changed the frequency and volume of vocalisations, so for example 43 per cent of cats vocalised more often. The duration of the changes relating to affection was 2-6 months, while other changes lasted around 2 months.

In terms of seeing the body of the deceased animal, 58 per cent of dogs and 42 per cent of cats saw the body, but owners reported no difference in behaviour changes between animals that saw the body and animals that didn’t. Most animals (73 per cent) sniffed the body of their deceased companion, but it is impossible to conclude what thought process was going on. For example, failure to sniff or engage with the body does not rule out recognition of the body or grief.

So what can we conclude? The authors acknowledge some limitations to the study. The survey was completed by owners who volunteered, and may have been biased towards those who felt they’d noted a change in the animal’s behaviour. Owners might also be biased in expecting grief or behavioural changes they associated with grief.

And we have to interpret the findings with care. Behaviour changes do not prove grief. For example, I was devastated when my cat Lil’ Puss died due to cancer. Yet the other cat, Michael, seemed to blossom and flourish in the wake of Lil’s death. As the authors of the study point out, behaviour change may be a result of reduced competition for access to the owner, or removal of a resource competitor for food or territory. Its often the case that animals in a household are of a similar age. Therefore changes in sleep may reflect age-related changes (e.g. older animals often sleep more), rather than grief as such.

What’s the point of all this? Ideally it would be helpful to understand how best to manage death in a multi-animal household. For example, are behaviour changes less pronounced in animals that have viewed the body of a deceased household member? Is there something veterinarians can alter in our practice to reduce grief in animals? Is there an easier way to distinguish grief or mourning from signs of illness?

You can read the full study here.