The classifications of rats and mouse




Before talking about Mouses and Rats could result interesting to occupy ourselves in the order of the rodents.

To this big group of animals belong a lot of breeds shared by a particular set of teeth constituted by a sharp couple of incisors just like chisels, with continuous growth. In this they are like the logomorph “cousins” (hares and rabbits), that however have got a second pair of incisors much reduced.

A curiosity is however the tendency to create problems, provided that we think to the really catastrophic damages that was created in Australia at the introduction and run wild again of the rabbits. Among the rodents we include the squirrels, (just for curiosity we remember the existence in Finland of a “flying” breed: Pteromys volans; the marmots (inhabitant of the Alps around the 2000 meters of elevation); the beavers (it is the biggest European rodent, by now confined in the valleys of the Elba and the Rodano, it was replaced in some areas by the Canadian cousin); the hot porcupine (it is the biggest representative of the Italian “rodent”, provided with strong stings and usually, if it is irritated or attacked, “it engages the reverse” and run backwards for jabbing the stings in the skin of the enemy); the nutria also called “Coypu” (of south American origin and was introduce the farming as a furbearer; some exemplars escaped and undomesticated have found colonies of a big numerical consistency); the edible dormouses (that start to create some damage in the floors of our housed and in the stone pines); the hamsters (in our latitudes are present only as pet) the lemmings (inhabitant of the conifers’ forests and the tundras of the North Europe) the voles; wood mousse; house mousse and sewer rats and rat of the roofs; breeds that we will talk over in a little more detailed way, for obvious reasons.


To the breed of Cricetids (subspecies Microtini) belong the voles and among them some breeds can cause damages of a great importance and some agrarian farmings, forestall and horticulturals. As examples of rural voles there are the apple orchard of Trentino and the Savi’s vole for the artichoke fields and other farming of a great value.

These rodents have got hypogean’s habits, in other words they dig tunnels on the surface and rarely they venture to go on a superficial trip, and we have to think about this for planning about a correct fight.

In some cases is useful to go on with agronomical practices (frequent and superficial treatment of the ground, the usage of the wredkiller and/or geo-pest controls) for rendering difficult the settlement of these little animals. In other cases was sufficient the broadcast distribution of baits activated by low toxic anticoagulants. In these circumstances is very important to control the inaccessibility of these treated sites to persons, particularly children, and non-target animals.

In the most difficult situations we can arrive to the digging of little deep holes more than one span where to put some bait points. We have to particularly pay attention in the coating of the drills with straw, garbage or grass.

The wood mouse can adapt to a lot of ambients from the deep woods, to the cultivated areas to the stores, where it contests the environment with the “house” mouse.

The damages can arrive to a great consistency above all soon after the seeding; as a consequence in this period and at the present of this infestation it is useful to intervene in the parametrical areas and next to Streets and irrigation systems, vessels that contain rodenticidal baits (with a low toxicity).

The troughs will have to preserve the baits from manipulations that are not desired protecting also from the bad weather and, logically forbiddening the availability from birds and other animals.

Mouses and Rats

They belong to the same breed of the wood Mouses, MURIDAE, but of a greater sanitary interest, belong the Mouses (Mus musculus) and the Rats (Rattus norvegicus and Rattus rattus)

They have a slender body, a scaled tail almost without hair and long almost as the body or more for the black Rat of the roofs.


At this point a famous rodent and for this reason it is called from almost all the exterminators with its Limmaean denomination. The Mus musculus is an infesting entity that can settles each site, from the washing machine that we have in our houses (where its instinct preserve it from the undeniable risks of the moving parts; thinking about the rotating drum of the linen during the centrifugation!) to the high technologies of the data processing centres that are computerized where its latent induction is seen just like a complete catastrophe). More often we find it in the agricultural and food chain where it can be defined just like an endemic entity, with alarming epidemic outbreak.

“Our” house mouse can arrive to a weight of 30g, but it is a good eater: from three to five grams during a day (proportionally a man of a weight of 70kg could eat from 7 to more of 10 kilograms during a day) in return it drinks not much (from 1 to 2 cubic centimetres during a day) but it can remain without drinking for a long period. It produces 1,2 cubic centimetres of urine during a day with 2 grams of excrements scattered in little “boles” the animal lays with a constant frequency for all the period of its activity that generally is serotonin and nocturnal. In justification of this also its feeding is distributed in 10-15 snacks (from two hundred to five hundred milligram for ingestion). Effectively this last one datum could not be put in parenthesis because it represents a characteristic that we must hold in great esteem in the program of fighting: in front of a tester of this strength we may have guns and adequate applicative techniques. The bio-ethological data most important are: the during of the life in conditions of captivity to four years, life expectation (in natural conditions) estimated to around 6 months. Sexual maturity after two months and a half from the birth, pregnancy of 20 days as the weaning; the number of litters during one year for each female 6-10 for fifty infants.

Psychophysical characteristics of these Muridae can be summarized in a notable curiosity tempered by the fear, and however justified, with not evident phenomena of neophobia (fear of the novelties). Furthermore, they presence exceptional performances; they can jump up to 30 centimetres, they fall down without damages from heights highest than 2 meters and they pass through holes bigger than one centimetre of diameter and they ca climb up n every surface: they are funambulatory mini athletes.

It is necessary to hold in great esteem of this highly invasive characteristics in the valuations of rat-proofing.


The fighting against little mouses usually resolve itself with their victory, because these Infesting entities are provided, as we have seen, of excellent psychophysic characteristics, but also of a great physiological resistance against the substances that more commonly are used as rodenticide. This complicate a lot the realization of fighting intervenes also because in some cases are used baits whose active principle is “active” against the Rats, less or for nothing against these more little rodents.

The impostation of the fighting that (except for very rare exceptions) is spreaded out in confined areas and is based on the general valuation of the environment where we want to operate. The area to be treated must be divided into infesting areas, at risk areas and it is just as important to locate the infesting pressure or better the ways in which it is presumable to assume the arrive of the “colonizers” with the sharp teeth.

Once it is monitored the interventing area, it is identified the “modus operandi”, that as a rule it is constituted the interventation at a maintenance and a protective level: seal the passages, execute nets and destruction and remove at the same time refuge areas (this phase can be preparatory or can be executed successively to the placing of the baits). After having created the premises for the positioning of the bait points, it is necessary to fix their number and the relative places. Each bait point that is located must be defined for the kind of bait (food base), the amount of the bait and more idoneous sort of protection to serve the purpose.

In some cases when there is a particular difficulty can be useful to effect a chumming treatment (pre-baiting) with the use of placebo; this with the intention of valuing the entity of the infestation, the food habits and/or induce the habit to the bait that we will want to use. A kind of dress-rehearsal, leading in the formulation frequently adduced in the erudite literature, but very little adopted in the common practice: just like all the technical possibilities it can be effective in the dimension in which it is used and where it is really necessary, and a further case of applicability of the chumming is the one of hardening the little mouses to areas of feeding less or nothing interactive with the activities elaborated in the sites of murine drainage. Once collocated the bait points they must be restored and then arranged to the exigencies that are created.

Once finished the phase of drainage is often useful to effect a maintenance finishing, when is identified the necessity, but is important the critical verification of the Treatments. When this is done we have to plan the calendar of interventions with the intention of maintaining the obtained results, and then bettering them and, at the same consolidating the prevention the prevention of reinfestation risk: with intervenes against the contamination, with meticulous inspective monitoring, with the valuation of the providers, and, with the not marginal fact, with the improvement of our knowledge’s and capabilities in the context of the too frequently desegregated matter of the environmental hygiene.

This is worth in the case of an intervention led up to the valuation of a contracted service; must be remembered that the Law upon the industrial safety refers to the hygienic risk or the need to remove or at least reduce the risks to a minimum, of every kind, at the origin. At a professional level everything must or should be attested on cards for consenting the valuations of results along all the interventation phases and for all the period of time when the calendar is concreted. This common phase for all the interventations of draining for every infesting breed will be enlarged far away in a specific chapter.


This breed is arrived in our distributional areas from the very distant Mesopotamia, probably taking advantage of the sea traffic with the trireme of the Roman Empire.

It is certainly the cause of the more important epidemic of plagues in the medieval age and still today it represents a potential vector of a lot of infective diseases: salmonellosis, leishmaniosis, verminosis and a lot of other.

This is sprightlier of the sewer Rat, generally it colonizes the garrets and the elevated structures of the silos and usually the crowns of the trees, with a certain preference for the maritime pines and the palm trees. The males of this breed can reach a weight of 300/500 grams, the lighten of the body can reach the 16/21 centimetres, while the tail is longer than the body of at the minimum of a couple of centimetres. The lears are fairly long and generally can, if they bare folded up, cover the eye. The diet is omnivorous and they prefer the proteins of a vegetable origin and daily it reaches to outweigh the 20 grams of dry substances and 20 millilitres of water, but the black rat of the roofs can remain without drinking for more days. The excrements and the urine are a little lower than the ingested quantities. The during of the life in captivity can reach the six years, while generally in nature it cannot to exceed one year.

The sexual maturity arrives after two months and a half from the birth, the gestation period perdures for three weeks, and the weaning four. The broods for each female are between six and eight for a number of new born of 34 subjects.

In this breed the neophobia is strong and above all in the population settled from a certain period and for this reason with consolidated habits. The psychophysic characteristics render it a capable climber (it can claims inside vertical pipes of a diameter of 10 centimetres and for this reason it can appear in the toilet bowl and than mysteriously disappear) a good jumper and an average swimmer.


When we want to fight against the Rattus rattus we must to take an account of the neophobia of this breed and for this reason every interventation of drainage is good to be reminded when the eradication is done. The Treatments are planned with some methodological analogies already examinated in the chapter Identification of the infested places and, of the areas at risk and also of the possible infesting ways.

These places are recognizable for the presence of greasiness (betalanolina), excrements, gnawings, communication trenches and burrows or “nests”. Once localized the infestation we pass to the positioning of the baits in an adequate quantity and with adequate bait for every typology. Also in this case can result useful the technique of the chumming with the placebo.

As a rule the calendar of Treatments involves inspectional/applicative interventations with a monthly cadence and not-invasive and meticulous interventations that must take ever an account of the agility and climbing capabilities of this breed. For this reason we must pay attention at the presence of pipes, wires, poles, and every other thing that permits to our funambulatory rat of “entering”, therein enclosed the walls that are not perfectly smoothed.

Also in this case is good in the professional interventation to formulize the data about the Treatments with correct and detailed certification.


In much more than a century, starting from the Russian scrublands, this breed has occupied the almost totality of the planet. In fact, in the second half of the XVIII century probably for a terrestrial phenomena of a great range, it starts the immigration that in few decades permit to it to invade the Europe to invade and, then with commercial traffics it arrives to the Americas and so on into the other continents.

It is a vigorous animal and it is also aggressive and it takes away the space to the Rattus rattus and into short time it captures all the subterranean habits, above all if they are connected to the water system or sewerage.

The males can exceed the weight of 600 grams with the same dimensions of the rat of the roof, but with a more corpulent figure, with the tail shorter than the ears and more little eyes. In the laboratory it can live to 7 years, but in nature the life expectancy hardly arrive to 10/11 months. The sexual maturity arrives between the two months and a half and three months. The pregnancy is a little upper the three weeks and the weaning four weeks.

Only one female in one year can have an offspring constituted by 40 units into 4-5 clutches. The solid diet is omnivorous, with a certain preference for the animal proteins and it arrives to the 10% of the corporeal weight with a water contribution just a little lower; urines and excrements in proportion. Psychophysical and sensorial characteristics indicate animals with scents, taste, and sense of touch-hearing very developed; while they can be reliant on a keen sight fairly reduced. They are very strong animals and they can have a high jump of about 80 centimetres and long jumps (from a stationary position) of 10/20 centimetres highest than one meter and with the run-up they double the performance; they are capable of superficial and breath-held swims very respectable; they can dig long tunnels into the ground perforating thin concrete barriers and tender metals.


The majority of what was said for the precedent breeds is true also for the surmolotto, or sewer rat how it is also known (look at the neophobia of the black rat) so it is important to leave everything alone, happening with rat-proofing practice and of Maintaining only after the eradication phase.

For the wide-ranging interventions procedure should (if it is possible) to follow a centripetal progress, with sanitary barriers that forbid to isolated guys and also alarmed of migrating to other sites, scattering micro infestations that can free themselves in short times for the high reproductive capability of the breed.

A particular attention must be put in the protection of the baits because usually the habitat of these rodents converges with the ones of not-target animals and, in some cases with those of the human being.


It is a good regulation to hang to the intention of erasing the problem, it is not regular to reduce the infestation without ever arriving to the solution of the problem in a more resolute endings. As a rule this involves a solid intervention realized in two or three phases. And here starts the more sensitive phase and, in our opinion very important: the maintenance of the results. Why it is hard? Above all because when it is finished the state of emergency, we tend to decrease the attention toward the problem and furthermore for the reason that the little remained exemplars tend to elude the usual monitoring, and in fact requesting a larger inspective engagement.


Accessorial treatments are fundamental because they have got the purpose to render arduous a new infestation and they become, in the possible projections, a kind of “prevention”. The Treatments against intrusion involve the affixing of barriers and nettings against the rats. In this phase it is very important to analyze the closing systems (doors with photoelectric cells or automatic shutter) adopted to the specific exigencies, above all in the industrial context or hospital facilities.

For the territory should be good to pay attention to the sewer system, to the drainage basins, and also to the agrarian societies. This chapteran should arrange in a good position in a context for the redevelopment of the ground and/or “sanitary” engineering.


This sight of the murine survey is a part of the management of the information. The papery gathered data or also electronical data permit of measuring and assessing the results, with a consequential optimization of the next treatments. It is natural for everyone of us that get ready to play with cards to reorder them in compliance with adequate patterns: just for examples all the diamonds at a part and good ordered from the bottom to the top. The possibility of winning is also based on the facility of controlling the cards and this is facilitated by the fact of seeing them in order in front of the eyes: the disorder should facilitate the mistake.