This is my fourth Sunday Read so it occurred to me that some introductions were overdue! I'm Leili, the founder of Supakit *waves hello*. I share my
zoo home in leafy London with larger-than-life Bengal girls Lyra and Lola (pictured above), and my partner Kevin - who runs Supakit with me and is also one of the world's most doting cat dads.
I started the Sunday Read because I love writing and cats, and I love writing about cats even more. But something happened this week that made me realise what I'd love to do with this blog.
Enter one of Supakit's most adorable customers, and her lovely Momma who wrote this post on Instagram...
When I read this post it had a huge impact on me. I've always wondered about the answer to this question, and you'd think that having founded a collar company I'd have at least some sort of view. But the reality is I'd always tried to avoid confronting the question.
I didn't put bells on my own two cats because I thought they'd find it annoying, even though I knew I probably should to cut down on their hunting antics. In fact - and this is something I didn't tell anyone on social media out of shame - Lola and Lyra brought a live blackbird into the house a fortnight ago. I managed to rescue it and take it to an RSPCA vet where I'm assured it made a full recovery but I felt terrible, and like a highly irresponsible cat owner.
I followed the comments in response to Madame Pearl's post, hoping a consensus on bells would emerge. But as the comments poured in (lovely comments, I should stress - I love the Instagram cat community) I still felt confused. Some mentioned evidence that bells can permanently damage a cat's hearing, but others said that wearing a bell is the only way to keep local wildlife safe. And then others suggested that bells only work in the short-term because cats soon learn how to hunt anyway, without making their bells ring.
But reading the comments also inspired me. I trained as a biologist and then became a science documentary producer before founding Supakit, and if there's one thing I know how to do it's get to the bottom of a story - distilling complex and confusing subjects down to straight facts.
So this week I'd like to try something. I want to go deep into the question of whether cats should wear bells. Like really deep, down to primary research papers rather than second hand sources (because I've found in researching this blog post that so much has been misreported). I hope this isn't a yawn fest - and if it is, be honest with me, I won't mind! But what I'd really love to do is to deliver the raw facts so that owners can make their own informed decision about bells. And if this works out well I might try and use this strategy to tackle other questions in future Sunday Reads.
Still with me? Ok then! Strap in for the Sunday Read!
QUESTION 1: CAN WEARING A BELL PERMANENTLY DAMAGE YOUR CAT'S HEARING?
This was the scariest thought that I came across in the debate - could I be permanently damaging my cat's hearing by making them wear a bell? First, a little about cats' ears. They are exquisitely designed, able to pinpoint sounds by moving around, and to hear at pitches way above and below the human hearing range (they use their higher pitch hearing to eavesdrop on mouse chatter - sneaky right?!).
But when it comes to noise-related damage cats ears are almost exactly the same as ours. In fact scientists use them as a model species to study noise-related hearing loss for this very reason.
Studies have shown that (just like in humans) cats exposed long-term to environmental noise at a volume of around 80dB do not experience any hearing loss as a result (Gourevitch, B. 2001). The bells on a cat's collar register at about 50dB. The decibel scale is a weird and non-linear one so just trust me that a 50dB noise is actually about 1000x less powerful than a 80dB one. So you can see that even the loudest bell will fall comfortably into the 'safe zone' for your cat's ears.
The upshot? Your kitty will not lose its hearing by wearing a bell long-term. What a relief.
QUESTION 2: DO CATS FIND THE SOUND OF A BELL ANNOYING?
This is a slightly different matter. There really isn't good data about how cats perceive bells. We know from the way the ear and brain work together to process sounds that cats, like us, are very good at phasing out sounds that are predictable or routine (Malmierca, M. 2014) (for instance I grew up in a house by a railway bridge and I never heard the freight trains going through each night).
But what we can't be sure of is whether a cat is irked by the sound of its ringing bell. I think the pragmatic thing to do here is work things out on a cat-by-cat basis. For instance, I thought Lola would hate wearing a bell, but in the process of researching this article I put one on her and guess what? No reaction!
I'm inclined to think that if you've gone to the effort of reading this article and care about your cat's welfare that much you're also probably a good person to be able to judge whether they're getting annoyed every time you put a bell on them, at least until somebody finds a way to interrogate the issue in the lab.
There is however just one last bit of research I want to mention here, because I thought it was quite interesting. In 2016 researchers in the UK reported a new medical phenomenon - noise-induced seizures in elderly cats (Lowrie, M. 2016). They studied 96 cats whose owners had noticed that they appeared to have seizures in response to certain sounds, and found that it really did seem to be the sounds bringing them on. Specifically, things that tended to produce lots of high frequency sound, such as jingling keys or - in two cases - the sound of a dog nearby scratching its neck and jangling its collar.
The authors were keen to stress that these were rare events. The average age for these cats was 15 years old, half already had a hearing impairment or were deaf, and a third were Birmans. And the good news was that they were able to treat the seizures with existing drugs. But if you notice your elderly cat experiencing the symptoms of a seizure (ranging from sudden muscle twitches while your cat is still alert, to the more classic type where they lose awareness and fall to the ground) then you should take them to the vet and consider whether their collar bell may be the cause.
QUESTION 3: DOES WEARING A BELL REDUCE HUNTING KILLS?
When I started delving into the literature, the picture looked confusing at first. Two studies in the early 90's in Australia found that bell wearing had no impact on a cat's predation rate, while a Mammal Society Survey found that bell-wearing cats killed more wildlife than non-bell wearers!
But all three studies only recorded the kills that cats brought home and asked owners whether they were wearing a bell at the time. That's problematic because you don't know whether other factors might be at play - for instance owners may be much more likely to put a bell on their cats if they are already avid hunters, which would skew the results.
In 2002, a study was conducted in Lancashire, England that tried to get to the root of the matter (Ruxton, G. 2002). The researchers enlisted 21 cat owners and asked them to follow a pre-determined bell-wearing schedule so that by the end of an 8 week period their cats would have worn a bell for half of the time. They were also asked to record the wildlife their cats brought home, and then the researchers crunched the numbers to see if the kills were reduced on the days that the kitties were wearing bells.
The results showed that without bells, the cats brought home an average of 5.5 prey a week, but when they were wearing bells that dropped to 2.9 a week - reducing mammal and bird hunting equally, by a total of around 50%.
"Equipping cats with bells seems to reduce their predation on wild birds and mammals...this practice can be recommended to owners seeking to reduce such predation."
A similar study a few years later also reported roughly similar results - which is always reassuring because reproducibility is the name of the game in science.
"Cats equipped with a bell returned 34% fewer mammals, and 41% fewer birds than those with a plain collar"
But it's also worth mentioning that besides bells, there are couple of other mechanisms that can be retrofitted to your existing collar, and have also been proven to reduce cat predation on wildlife.
The CatBib™ is a collar attachment that "works by gently interfering with the precise timing, and coordination a cat needs for successful bird catching". It was found in Australian studies to reduce predation on birds by around 50%, mammals by 80% and amphibians and reptiles by a third. (Calver, M. 2007)
Another option is the BirdsBeSafe® collar cover which is designed to give a visual warning to your cat's prey. An Australian study tested the collar covers over a period of 2 years, and found that they reduced captures of birds, amphibians and reptiles by 54%. However, they didn't reduce predation on small mammals, which they attributed to the poor colour vision of mammals (which would make them less able to see the colour warning signal of the collar). (Hall, C. 2015)
It is also worth noting that a shorter study of the same BirdsBeSafe® collar covers in the USA (two three month periods) found an even stronger anti-bird effect (an 87% reduction) and even an anti-mammal effect of up to 50% in the fall, so there are probably differences in effectiveness depending on the particular wildlife in your area. (Wilson, S. 2015)
QUESTION 4: DO CATS LEARN HOW TO OUTWIT THEIR BELL?
I keep seeing this one pop up - and frankly I'm not surprised. My two cats manage to outwit me at every turn, so it's not hard to imagine them finding a way to outsmart a small tinkly bell!
In the Lancashire study mentioned above, the researchers did not find any evidence that the cats learned to adapt their hunting strategy to outwit their bells. However, this was a really short experiment - only 2 months in total, so it could be that they didn't look for long enough. (Ruxton, G. 2002).
If you notice that your cat appears to be circumventing whatever anti-hunting mechanism you're using, then it is well worth considering switching to one of the alternatives listed above.
And that's it! For those of you who have made it this far, thank you for joining me on this whistlestop tour through the science behind bell wearing. I really hope it gives you the tools you need to make up your own mind. Here at Supakit you can order your collars with or without a free bell, the choice is entirely yours (and if you change your mind the bell is easy to remove or put back on).
Does your cat wear a bell on its collar? I'd love to hear your thoughts in the comments below. And if there are other questions you'd like me to explore in future Sunday Reads - just ping them my way!