Are attacks on our rats justified?

THE headline in the Dublin People declared “Locals Battle A Plague Of Rats”.

And according to Carol Shortt, Demond Avenue, Dún Laoghaire the rats are “running all over the place ... my boyfriend and other neighbours have killed several over the last few days with shovels and forks but they keep coming”.

Headlines about rats almost always include the word ‘plague’ – ancient folk memories persist for generations. Every culture has its demons. Rattlesnakes and black widow spiders spook Americans, sea-wasps and sharks worry Australians. Our own worst nightmare is the humble rat. Bubonic plague, the dreaded disease of medieval Europe, killed 31,000 Londoners in August 1665. It was caused by a bacterium carried by rat fleas – when the rats die, the fleas move onto people.

The lethal bearer, however, was the black rat, now virtually extinct in our part of the world. The brown one, which arrived in the 18th century, ousted him. We should be thankful for the deliverance; there hasn’t been an outbreak of plague on these islands since its arrival.

But rats still revolt us. They wallow in filth, carry disease and have naked snake-like tails which give us the creeps. Their cousins the squirrels have fine bushy tails; needless to say, we love them.

I’ve seen more rats than usual in the last few weeks, so has there been a population explosion? Could this be a case of increased visibility as rats seldom venture out in daylight? Exposure is risky; cats may be on the prowl and Carol Shortt’s boyfriend may be waiting with his shovel. Activity increases just after sunset and there’s another scramble for food as dawn approaches. With the long hours of daylight at this time of year, corners may be cut; individuals driven by hunger emerge while it’s still bright. The most visible ones are often youngsters, denied access to food by dominant animals and displaced in the Mafia-style extended-family wars which are the norm in rat society.

But it’s not all down to visibility. Rat numbers rise and fall in roller-coaster fashion. These opportunistic animals make hay while the sun shines. They will breed in any season if the weather is mild and food is plentiful. A female may become pregnant when only two months old and produce young five times a year. There are usually seven to nine babies in a litter, occasionally as many as 15. Pregnancy lasts three weeks. Weaning takes three more. Then, the mother is ready to start again. Each female could, in theory, add 50 youngsters to the population in a year but field studies suggest that annual production is about half of that.

Conditions this summer were probably ideal and a rapid succession of litters might account for the Dún Laoghaire ‘plague’. So will the town be over-run like the village of Hamelin? To get a handle on the situation, we need to consider the other side of the equation – death.

Life for a rat is ‘poor, nasty, brutish and short’. Scavenging in rubbish dumps, drains and sewage out-falls is a hazardous business. Black-backed gulls quarter the dumps. Cats and foxes prowl farms and suburban gardens. Stoats, owls and badgers are a hazard in open country. Flash floods trap and drown rats in storm-water drains and sewage pipes. Disease is rife; poisonous and noxious substances are everywhere. Food supplies may suddenly collapse as the population explodes. Rats can live for up to three years in captivity but life-expectancy in the wild is about half of that. So is a vendetta against the Dún Laoghaire rats justified? Rats bite people, but were you ever bitten? Do you know anybody who was? A bird-ringer colleague of mine, working at dusk, seized what he thought was a bird caught in his mist-net. It was a rat. So rare was a case of a rat bite that the doctors at a large Dublin hospital had to consult textbooks to decide what shots to give him.

The black rat of bubonic plague fame entered houses and lived close to people, even sleeping in mattresses and piles of clothes. Brown rats, however, keep their distance. Is a massacre necessary when only one in every 20 alive today is likely to survive the winter? Nobody’s perfect. Live and let live.