A common reason for pet-keeping, which goes right back to our Stone Age days, is that an animal can offer valuable protection against intruders – as a ‘living burglar alarm’.
Dogs have been bred for this purpose for centuries – and they have very strong instinctive protective behaviour, which allows them to carry out this role effectively. Some dogs are selectively bred specifically to be guard dogs or watchdogs, but most pet dogs perform this role very effectively.

For the average household, you do not need a big breed or a specially trained animal. Most pet dogs are excellent guardians of their own territory.   Dogs have acute hearing, and their sense of smell is millions of times more sensitive than our own.

Any dog can act as an early warning device – they will often let you know if anything out-of-the-ordinary happens. The tiniest breed – such as a Yorkshire Terrier – can have a loud bark, which will alert the householder, and which may deter any would-be burglars.
 In fact some of the bigger breeds – such as Retrievers or Labradors – may not make as much noise as some smaller animals. I know some people who keep two dogs – one little ‘yappy’ dog to make a loud noise, and one big strong-looking animal – who might not bark as much, but looks more intimidating if a prowler looks over the fence.

Most dogs do not need to do anything other than making a noise – the presence of a noisy watchdog has been proven to dramatically reduce the incidence of break-ins. In fact, having a dog that does physically attack intruders can be a liability. A dog may not be able to tell the difference between an enemy and a friend – and it can be very distressing if the milkman, the postman or a visiting friend is bitten.

If you think your dog may inflict an injury on an intruder, you must be sure to put up signs warning of a dangerous dog on your premises. It would also be sensible to take out insurance to cover you in case you are taken to court for damages.

Dogs are the most popular ‘intruder alarms’, but other species can also play a role. In Scotland, whisky distilleries are traditionally protected by flocks of geese.  

When I was working as a vet in Scotland, I was carrying out a routine visit to a farm. I had just stepped out of my car, when six geese came running around the corner towards me, hissing and hooting. I presumed that they were just noisy bluffers, and so I decided to ignore them, hoping that they would back down.  

However as I stepped forward, two of the geese lunged at me, pecking my lower legs and my hands, and the rest of the flock fluttered around me, as if they were closing in to finish me off. I was back in my car within seconds, and I did not budge until the farmer had penned the geese safely out of the way.

If you do not want to keep a pet, there is an alternative. You can buy a ‘bark in a box’ – which is a black metal box containing a movement sensor and a loudspeaker. If the machine detects movement, a switch is tripped, and the loudspeaker emits the noise of a terrifyingly aggressive dog barking.   You can still put up a sign telling people to ‘Beware of the Dog’, but you do not need to insure the box – it definitely does not bite – or peck!