Rats in Royal Ascot

Rats have been present in Royal Ascot even before the development started here, but the most visible indication has been those that are occasionally run down on the roads by vehicles. You will also all be aware that there is an extensive system of rat bait traps round The Paddocks building.

Recently rats have been noticed in some of our parks in the daytime, and RAMPOA consulted the EMC to advise on the situation and, if necessary, what action should be undertaken. The EMC advised that a pest controller be consulted, and while expressing concern about the possible effect of bait traps on field mice and other small mammals, the committee agreed that the most effective way to prevent rat numbers increasing would be by using live bait traps.

At the advice of the pest controller we are putting out bait traps in the area of the playpark between Cheltenham Ridge and Chestnut Ridge on Parade Ring Road – this is where there have been several sightings of rats. An inspection of the area found a rat burrow next to the electrical substation, and 14 bait traps will be set out along the walls on either side of the playpark. These bait traps are tamper-proof, but we still advise parents and carers not to let small children near them. This will be a trial to see whether we can reduce their numbers effectively.

According to the pest controllers the rats are probably spreading away from The Paddocks because of the effectiveness of the control measures there. We advise all precincts to be particularly aware that rats could spread into their precincts. All keep their refuse rooms quite clean and rat-free, but you may not notice them in the open areas within your precincts – they invariably make their burrows under walls or other constructions (fixed bins, electrical substations, etc), and usually run along the bottom of walls where in time there will be a clear rat path.

More about rats and rat biology

Two rat species have become closely association with humans. The rat we have in Royal Ascot is Rattus norvegicus, the brown rat – this is one of the largest rat species and while the average size of male adults are about 550g, large individuals can grow up to 900g in size. In spite of its name, Rattus norvegicus originated in northern China and spread into Europe during the 1500’s. By the early 1900’s it had distributed to all continents except Antarctica.

The other species associated with man is the black rat, Rattus rattus (although colour can also brown or grey). They most likely originated in eastern Asia, but evidence suggests that they moved into prehistoric Europe after the last Ice Age. However there have been successive introductions through trade routes on land and sea, and today black rats are widely spread in Europe, central and eastern Asia, central and southern North America, and in the coastal areas of other continents. They are not as widespread as the brown rat, and in many areas they have been displaced by brown rats.

Rattus norvegicus - the brown rat Rattus rattus - the black rat

Brown rats burrow extensively in a suitable substrate, usually using structures or fixed objects as the roof of their burrows. They are good swimmers, but are poor climbers (unlike the black rat); the brown rat is very sensitive to vibrations and can communicate ultrasonically. They are true omnivores and will eat almost anything, but cereals (like grass seeds) form a substantial part of their diet. They will be attracted to areas where there are food refuse, and they learn quickly and adapt their behaviour to exploit new and easily accessible sources of food.

Under suitable conditions they are prolific breeders, females can have up to five litters a year, commonly numbering about 7 per litter (although the litter size can be up to 14). They reach sexual maturity in about 5 weeks, and the maximum life span is about 3 years, but most probably barely survive longer than 1 year in the wild. Brown rats live in large hierarchical groups, and if a large fraction of a rat population is exterminated, the remaining rats will increase their reproduction rate to restore their numbers.

Like all rodents, brown rats may carry pathogens that affect humans, but in normal situations where contacts between rats and humans are scarce, transmission of diseases directly from rats to humans is rare. Cats coming into contact with rats may transmit some of these pathogens into homes where they could affect humans. Contrary to popular belief, the brown rat is not responsible for spreading bubonic plague, in fact the two major plague outbreaks in Europe occurred before brown rats arrived there – the black rat, Rattus rattus, was a carrier of the fleas transmitting the bacterium and was most likely responsible for the plague epidemic in the 6th and 7th centuries and the Black Death from 1345 onwards; this epidemic did re-occur during subsequent centuries until the late 1800’s. The bacterium today is endemic in only a few rodents like ground squirrels and wood rats.

A last word about Rattus norvegicus – the common white laboratory rat and domesticated rat pets are all Rattus norvegicus that have been bred for man’s specific purposes.