The Rat: Information

All this information has been gathered from newspapers and the web sites of companies and environmental agencies. The aim of presenting this information is to explain the serious problem that we face: pest control and the means we currently use to eliminate pests.

LATEST NEWS:
“ABC” newspaper (Friday 13/04/07), page 72-73
Headline reports that, according to Adena (WWF), poison has killed 20,000 endangered birds of prey in the last 15 years. Environmental organisation, Adena WWF complains about total impunity for the use of poisoned bait that has been banned since 1983.
Further details: http://www.wwf.es


THE RAT:

Feeding: Omnivorous. In urban environments, basically rubbish and human waste; the wild specimens live off cereals and seeds, including meat, insects and a wide range of materials in their diet, such as paper, wood, rubber, lead, tin, and plastic, hence causing frequent damage to water and electricity pipes. The common rat can eat one third of its own body weight each day. Omnivorous and opportunist, it lives off a very varied diet, even though, in the city, it usually feeds on rubbish and waste, while the wild specimens in the country prefer cereals and nuts, although meat is also an important component of its diet. The species has a highly developed sense of caution and mistrust for new or unknown food items, so poisons are not usually very effective in the fight against the common rat. It has been shown that faced with a new food item, the colony sends one individual, from the lower levels of the pecking order, to try the bait. If the rat dies after eating the bait, the rest of the colony is immediately on the alert, as they relate this death to having eaten the bait and avoid it in the future, so treatments of this kind become less and less effective.

For acute poisons to be successful, experts consider it vital that most of the population eat the lethal dose quickly. To achieve this, a suitable bait is used on the colony prior to offering them the poisoned bait. In any event, it should be borne in mind that the dead rats are a serious health threat, not just for man, but for creatures that eat them too, so the dead bodies should be eliminated, preferably by burning them.

Main problems: Damage to food (for human and farmyard animals) and to the fields where the crops grow are the main problems attributed to rats, because of its capacity to damage food. It is estimated that world wide losses caused by rats is 10% of the crop, not only from directly eating them, but also because of the destruction and contamination that they cause. Some studies have shown that a rat can eat 20 kg of grain per year, expel 25,000 pellets of excreta (excrements) and 6 litres of urine, apart from shedding thousands of hairs, which is why they have been defined as “a perfect contaminating machine”. They also require control because of the fact that they can spread diseases.

Information taken from: SIERRA DE BAZA PROJECT 2005


It is important to control this species, not only because of the enormous financial losses that it can cause as a consequence of contamination and damage to stored produce and the loss of prestige inherent in this contamination and damage, but also because of the fact that it can transmit serious diseases: Wei’s intestinal infections (Leptospirosis), bubonic plague (transmitted by the rat flea) and typhus (transmitted by the rat louse).

Information taken from: Desma pest control.

The rat is the most harmful and most widespread species in Spain. It is found both in the city and in the countryside, always in low lying damp areas, like sewers, ponds, rivers, etc. It always needs to stay close to a water source as its need for water is considerable. It is omnivorous and adapts its diet to the habitat it lives in. It causes great damage, as it destroys all kinds of materials, such as doors, light fittings, wooden beams, electric wiring, hosing for all kinds of cables, etc. They are also a real pest for crops.

Rats are considered highly dangerous, due to the fact that they can inoculate, transmit and pass on many diseases to people.

Just a few years ago, they were the main scourge of mankind. Rats carry serious diseases like bubonic plague, rabies, trichinosis, swine pest, recurring fevers, typhus, trypanosomyasis, tularaemia and many others. They pass them on to people by direct inoculation or through other mammals that they have directly infected, like dogs, cats and cattle. Or they can infect people through insects like fleas, bugs and the invisible mites that so easily invade homes, attacking people, causing dermatitis and triggering allergies.

Recent periodic studies that have been done in Europe and the USA show that the percentage of rats carrying parasites, which can be highly dangerous if people come into contact with them, is two out of every three rats.

Information taken from: SaludAmbiental.net



Symptoms on swallowing the poisons:

Acute Poisons: These are the poisons that kill the animal immediately after a single intake, e.g. 30 minutes. These products are extremely dangerous. Such rapid action could cause the problem of the rat not eating the entire lethal dose before the first symptoms appear, meaning that the rat is warned of the danger and avoids the bait and can warn its peers.

NOTE: When faced with a new food item, the colony sends a dominated animal to try the bait. A rapid death after eating the bait alerts the whole rat population, who relate the death of the rat with eating the bait, so the treatment becomes less and less efficient. Acute poisons will be successful insofar as they manage to tempt most of the population to swallow a lethal dose quickly. Usually, the colony is baited with a suitable bait before the poison is placed (e.g. zinc phosphide). Chronic Poisons: These products take longer before they act and they have to be taken in several doses. They act as anti-coagulants, provoking death from internal bleeding.

One of the advantages that these products have is that the symptoms do not appear until the rat has had the chance to take a lethal dose. They are also easier to use and comparatively safer. In general, the rats will stop eating the poisoned bait about 7 days after it has been first placed, due to the death of many of their members. Major control can be achieved after 4 or 5 weeks. (E.g. warfarine)

Information taken from: elsitioagricola.com


For further information, check the different sites that you will find on the internet with the denomination of Common Rat (Rattus novergicus), Grey Rat or Sewer Rat.