Brodifacoum is a highly lethal 4-hydroxycoumarin vitamin K antagonist anticoagulant poison. In recent years, it has become one of the world’s most widely used pesticides. It is typically used as a rodenticide but is also used to control larger pests such as possum.

Brodifacoum has an especially long half-life in the body, which ranges to several months, requiring prolonged treatment with antidotal vitamin K for both human and pet poisonings.

Rats (oral) 0.27 mg/kg
Mice (oral) 0.40 mg/kg
Rabbits (oral) 0.30 mg/kg
Guinea-pigs (oral) 0.28 mg/kg
Squirrels (oral) 0.13 mg/kg
Cats (oral) 0.25 mg/kg
Dogs (oral) 0.25 — 3.6 mg/kg
Birds 1 mg/kg — 20 mg/kg
Fish 0.04 mg/kg

Three main pest species in Australia and world-wide:

Norway rat – Rattus norvegicus also known as brown rat, sewer rat and wharf rat.

Roof rat – Rattus rattus – also known as black rat and ship rat.

House mouseMus musculus or Mus domesticus.

Distinguishing features

Norway Rat – stocky body – adults weigh about half a kilo – slightly larger animal than the roof rat – makes burrows – found wherever humans live – blunt nose – small close set ears which do not reach the eyes when pulled down – semi-naked scaly tail which is shorter than the head and body combined – coarse fur brownish, reddish-gray or blackish on top – whitish-gray under belly.

Roof Rat – slender body – tail as long as body and head combined.

House mouse – small slender – slightly pointed nose – black protruding eyes – large, scantily haired ears – nearly hairless tail with obvious scale rings – adult about 2/5 to 4/5 ounces – generally grayish-brown with a gray or buff belly – some are white-footed – jumping mice have a white belly – harvest mice have grooved upper incisor teeth.

Rodent senses – physical abilities

Excellent hearing, smell, taste and touch: Rats have poor eye-sight beyond three or four feet – excellent sense of hearing, smell, taste and touch – highly sensitive to motion up to 30 to 50 feet away – use sense of smell to locate food items and recognize other rats – rely on their sense of smell to recognize odors of pathways, members of the opposite sex who are ready to mate, differentiate between members of their own colonies and strangers, and to tell if a stranger is a strong or weak individual.

Hearing: Norway rats use hearing to locate objects to within a few inches. This highly developed sense, combined with their touch sensitivity, can pinpoint someone rolling over in bed to a six inch area. The frequency range of their hearing (50 kilohertz or more) is much higher than that of humans (about 20 kilohertz.)

Touch: Norway rats have a highly developed sense of touch due to very sensitive body hairs and whiskers which they use to explore their environment. Much of a rodent’s movement in a familiar area relies heavily on the senses of touch and smell to direct it through time-tested movements learned by exploration and knowledge of its home range. Rodents prefer a stationary object on at least one side of them as they travel and thus commonly move along walls, a fact which is very useful when designing a control program.

Taste: Their sense of taste is excellent, and they can detect some contaminants in their food at levels as low as 0.5 parts per million. This highly developed taste sensitivity may lead to bait rejection if the rodent baits are contaminated with insecticide odors or other chemicals.

Norway rat
Roof rat
House mouse
450 gms
260 gms
20 gms
Tail to body length
Shorter than body and head
Longer than body and head
Same length as body
Fur colour
Red to brown
Grey to black
Brown to grey
Gestation period
22 days
23 days
19 days
Number of litres
5 to 6 per annum
4 to 5 per annum
6 to 10 per annum
Average life span
1 year
1 year
1 year
40 to 50 metres
40 to 50 metres
3 to 10 metres
Preferred food
Omnivorous Garbage, cereals, meat, fish
Omnivorous Vegetables, fruits, cereal grains
Omnivorous Cereal grains
Food Intake
20 to 30gms a day
15 to 22gms a day
3gms a day
Water Intake
20 to 30ml a day
15 to 22 ml a day
1ml a day

Types of rodenticides

Ready-to-use-baits: mostly in the form of treated whole grain or pellets, available in bulk or throw-pack form.

Concentrates used in the preparation of food or liquid baits, or perhaps as a tracking powder.

Paraffin blocks usually treated grain matrix of paraffin wax, suitable for areas with excessive moisture.

Bait stations available – Protecta lockable – cardboard.

Signs of a rats or mice infestation: Since rats and mice are active at night and are rarely seen during the day, it is necessary to recognise signs of their activity.

Droppings and urine: Most people first recognise rodent problems by finding droppings or urine stains in and around buildings. Rodents usually have favorite toilet areas but will void almost anywhere. Old droppings are grey, dusty, and will crumble. Fresh droppings are black, shiny, and putty like. Rodents urinate while running, and the streaks are characteristic. The urine glows under ultraviolet lights and glows blue-white when fresh. A good indicator that the rodents are taking the bait is the change in colour of their droppings.

Gnawed objects: Rodents gnaw every day in order to keep their teeth short and sharp. Rats also gnaw to gain entrance or to obtain food. Teeth marks on food, building materials, wire, and edges of beams are indications of gnawing. They gnaw holes in wooden walls, pressed wood, and posts. Fresh gnawing in wood is usually light-coloured with sharp, splintery edges. Old gnawing is smooth and darker.

Runways: Rats habitually use the same paths or runways between harbourages and food or water. Outside runways and paths 2 to 3 inches wide and appears smooth, hard packed trails under vegetation. Indoor runways are usually found along walls. Undisturbed cobwebs or dust indicates that the runways are not in use.

Rubmarks: Along runways, dark greasy rubmarks appear from contact with the rodent’s body. Rubmarks on walls appear as black smudges left by the rodent. New rubmarks are soft and will smudge. Old rubmarks are brittle and will flake when scratched. Rafters may show swing marks of roof rats.

Tracks: To detect rodent activity, spread dust material like talcum powder along obvious or suspected runways. Inspect any animal foot prints found – note rats have 4 toes on front feet and 5 toes on hind feet – also rat tail drag marks will show in the powder.

Burrows: Norway rats burrow for nesting and harbourages. Burrows are usually found in earth banks, along walls, under rubbish and concrete slabs. Freshly dug dirt scattered in front of 3 inch openings with runways leading to the openings are characteristics of these pests. Burrows usually are 18 inches deep in most soils. Slick hard packed runways indicate an old established colony.

Live rats and any dead rats: The sighting of live rats is a sure sign of infestation. Sightings in daylight indicate that there is a large infestation. Mummified rat carcasses may indicate a former infestation although many fresh carcasses suggest disease or poisoning.

Sound: Usually rodent sounds are heard at night or in quiet areas. Rodents moving at night often scratch, gnaw, and fight. The young often squeak while in the nest.

Pets: Usually dogs or cats will act strangely, especially at night, if rodents are present.