• Rattus Norvegicus (Brown rat)
• Rattus Rattus (Black rat)
• Mus musculus (House mouse)
All are described as commensal rodents “sharing one’s table”.
Brown rat – (greyish brown, reddish brown)
Slightly larger animal than the roof rat. The nose is blunt, the ears are small, the tail is scaly and shorter than the head and body combined. They burrow to make nests under structures, beneath concrete slabs and along stream banks.
Rattus Rattus (Roof rat) When necessary, roof rats will travel considerable distances for food. They can often be seen at night running along overhead utility lines. Roof rats have a strong tendency to avoid new objects in their environment and this can influence control efforts. These rats may take several days before they will approach a bait station.
Roof rats have an excellent sense of balance. They use their tails for balance while traveling along drinker pipes and are very agile climbers.
Rattus norvegicus/Rattus Rattus
When distinguishing the Norway rat from the Roof rat, pull the tail back over the body. The tail of the Roof rat will reach the nose. The tail of the Norway rat will not reach beyond the ears.
Rats in general
Rates see poorly, relying more on smell, taste, touch and hearing. They are considered to be colour-blind, responding only to the degree of lightness and darkness of colour. The average life of rats in a population is about six months, and rats rarely live much over two years.
NEOPHOBIA – new object fear.
Placing an unfamiliar object (such as a box) in the path of a rat effectively prevents it using that path, and is now classed as an obstacle. The rat will take several days before it will venture into the box and take the poison. Allow for one week before relocating the box if no feeding was found.
Rodent move for four main reasons:
a. food b. water c. shelter d. breeding partners these types of movement are termed “voluntary”. Movement by means of transportation in goods and by vehicles is “involuntary”. Female rats can move up to 340 m in one night and males 660 m. Rats reach a peak of activity ± 2-3 hours after the onset of darkness, and a smaller peak an hour or two before sunrise.
Rats do prefer a clean meal, keep this in mind next time you open your bait station and find a frog, spider and half a rubbish dump around the poison. Keep your poison clean and the bait station clean. Contaminated poison is a problem that leads to poor rodent control. For example:
a. the person applying the poison did not wash his or her hands and diesel has tainted the product
b. the rat has urinated on the poison (to keep other rats away)
c. too dirty (dust, feathers)
A rat run is usually from a food or water source to the nest. If looking outdoors a well-defined run will be narrow and clear of grass, indoors will take place against a wall overhanging pipes or cables and free of dust and cobwebs.
Grease marks are generated by several rats entering a small entrance, this is made by the oily layer mixed with dirt on the rat’s fur. (Looks like a candle burn mark)
Severity of infestation
When looking at an area and not knowing how much poison to place one should look for the following,
a. number of droppings
b. grease marks (entry and exit points)
c. foot prints (look for dust on pipes and beams, if there is no dust on one, but dust on another, it is a rat runway)
e. damage (rats need to chew all the time to wear down their teeth e.g.: electric wires, fittings, drinker pipes, timber lead pipes)