House Mouse
Description: Its tail is as long as its head and body length combined, and the tail is practically hairless. Its fur usually is a medium brown to dusky gray color with a lighter colored belly. The House Mouse can jump straight up about 12 inches, perhaps from the floor to a shelf or drawer pull, and if they jump against a wall, using it as a springboard, they can gain additional height. They can run up almost any vertical surface that is rough, such as wood, brick walls, wire mesh, or cables. The House Mouse can run horizontally along insulated electric wires, small ropes, or the telephone line that comes from the outside pole to the house. The House Mouse can squeeze through openings slightly larger than one quarter of an inch in diameter. They are able to get through any opening that they can get their head through, being able to squeeze the skull and skeleton down a bit to facilitate entry. They can jump down to the floor from a height of 8 feet without being injured, and can jump horizontally, from a standing start, at least 18 inches.
Biology:
A female house mouse can produce six to ten litters in her lifetime, with 5 or 6 mice in each litter. The gestation period is only 21 days, and those offspring are adults that can mate in only six weeks. In a one-year period a House Mouse is capable of excreting 18,000 fecal pellets. That’s 1,500 each month, or around 50 per day per mouse. One excellent detection tool available to the pest management professional is ultraviolet light. Both wet and dry urine deposits of rodents will fluoresce when exposed to UV light, which we also call “black light”. In a darkened environment you may be able to expose the presence of rodent urine on pallets, floors, or packaged products by passing a portable UV light over the area.
Habits:
It has relatively large ears and small feet. Once “home base” is established, the House Mouse may not wander very far from it. The female House Mouse may spend her whole life in an area no more than a ten foot circumference, possibly even within a single bag of grain. The need for water is very limited; the House Mouse generally is able to survive on the moisture that can be found within the foods that it eats, even grains and nuts. The House Mouse has two main periods when it feeds – at dusk and at dawn, in both cases in relative darkness. They can survive in a temperature of 24 degrees Fahrenheit for many generations, as long as food and nesting materials are available.
The sense of hearing in mice is excellent, and if you are moving around in their habitat they certainly will hear you coming and have plenty of time to scamper back to their hiding places. Mice gnaw on things; they commonly chew on electric wires, and are blamed for a high number of structural fires as this activity causes electrical shorts in a home.
Vole
Description: A vole is a small rodent resembling a mouse but with a stouter body, a shorter hairy tail, a slightly rounder head, smaller ears and eyes, and differently formed molars. Voles can grow to 4-8 inches depending on species. There are approximately 155 species of voles. They are sometimes known as meadow mice or field mice in North America.
Biology:
They can have 5-10 litters per year. Gestation takes 3 weeks and the young voles reach sexual maturity in a month. Needless to say, vole populations can rapidly grow from one or two to many within a very short period of time. Since litters average 5-10 young, a single pregnant vole in the yard can become 50 or more in less than a year. The average life of a vole is 36 months. Voles rarely live longer than 12 months. The longest lifespan of a vole ever recorded was 18 months.
Habits:
Voles are commonly mistaken for other small animals; moles, gophers, mice, rats and even shrews have similar characteristics and behavioral tendencies. Since voles will commonly use burrows with many exit holes, they can be mistaken for gophers or some kind of ground squirrel. They will readily thrive on small plants. Additionally, voles will target plants more than most other small animals. It is here where their presence is mostly evident. Voles will readily “girdle” or eat the bark of small trees and ground cover much like a porcupine. This girdling can easily kill young plants and is not healthy for trees or other shrubs. Voles love to eat succulent root systems and will burrow under plants or ground cover they are particularly fond of and eat away until the plant is dead. Bulbs in the ground are another favorite target for voles; their excellent burrowing and tunneling gives them access to sensitive areas without clear or early warning. A vole problem is often only identifiable after they have destroyed a number of plants.
Norway Rats
Description: The Norway rat is a larger, stockier rat that prefers to live near ground level. It is usually brown or grey with a body up to 10 inches long. Nests most often are in burrows dug in the soil, and it is commonly found moving through the sewer and storm drain systems under our cities and neighborhoods. Its fur is brown, its ears are small, its nose is blunt, and its tail is shorter than its body length. Norway Rats can enter through an opening no wider than half an inch. Preferred foods may include meat or fish, so it is common around seaports and waterfront areas. In residential areas it may feed on snails or pet food, and other names that have been applied to it are Wharf Rat, Sewer Rat, Ship Rat, Burrowing Rat, and Brown Rat. Rats are somewhat color blind.
Biology:
The Norway rat can breed throughout the year if conditions are suitable, a female producing up to five litters a year. The gestation period is only 21 days and litters can number up to fourteen, although seven is common. The maximum life span is up to three years, although most barely manage one. Rats are capable of producing up to 25,000 fecal droppings each year.
Habits:
Norway Rats are meat eaters. Stories emerge of pet rats attacking children while they sleep in their cribs, chewing on them to the extent they may even cause the death of the child. “Gnawing” is an important habit of all rodents. Gnawing is used to gain access by chewing through walls, doors, or outer packages. Gnawing is used to access water by chewing through pipes, including outdoor irrigation systems. Gnawing is used to acquire nesting materials by chewing on fabrics. Gnawing is also used to eat, by chewing on hard materials such as bait blocks or walnut shells.
Rats do not like daytime activity, and if you see them out and about during daylight hours it may be telling you one of several things: that they are extremely used to you and have gotten bold, they are ill, or there are so many rats they have run out of hiding places. Rats are suspicious, and are more likely to avoid contact with new things in their environment.
Roof Rats
Description: The Roof rat is a thinner, more sleek-looking rat than the Norway rat, with its tail noticeably longer than its body length. Its nose is more pointed, its ears are larger in relation to the head, and its fur is a much darker brown color. It is usually black to light brown in color with a lighter underside. A typical rat will be 6-8 inches long. It prefers to nest above ground level, in structures or foliage, perhaps as a way of distancing itself from the Norway rat, which is the more dominant of these two species. Roof Rats can enter through an opening no wider than half an inch. Preferred foods may include snails, nuts, grains, and fruit, so nicely landscaped yards are a preferred environment. Other names for this rat are Climbing Rat, House Rat, Black Rat, and Fruit Rat. Rats are somewhat color blind.
Biology:
In a suitable environment it will breed throughout the year, with a female producing three to six litters of up to ten young. Females may regulate their production of offspring during times when food is scarce, throwing as few as only one litter a year. This rat lives for about 2-3 years. Social groups of up to sixty can be formed. Rats are capable of producing up to 25,000 fecal droppings each year.
Habits:
Roof Rats can jump straight up about 2 feet and horizontally perhaps as much as 5 feet. “Gnawing” is an important habit of all rodents. Gnawing is used to gain access by chewing through walls, doors, or outer packages. Gnawing is used to access water by chewing through pipes, including outdoor irrigation systems. Gnawing is used to acquire nesting materials by chewing on fabrics. Gnawing is also used to eat, by chewing on hard materials such as bait blocks or walnut shells.
Rats do not like daytime activity, and if you see them out and about during daylight hours it may be telling you one of several things: that they are extremely used to you and have gotten bold, they are ill, or there are so many rats they have run out of hiding places. Rats are suspicious, and are more likely to avoid contact with new things in their environment.